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F/+HARD4
This website contains an archive of files for the Acorn Electron, BBC Micro, Acorn Archimedes, Commodore 16 and Commodore 64 computers, which Dominic Ford has rescued from his private collection of floppy disks and cassettes.
Some of these files were originally commercial releases in the 1980s and 1990s, but they are now widely available online. I assume that copyright over them is no longer being asserted. If you own the copyright and would like files to be removed, please contact me.
| Tape/disk: | Home » Personal collection » Acorn ADFS disks » Electron_User_Group » EUG_35.ADF |
| Filename: | F/+HARD4 |
| Read OK: | ✔ |
| File size: | 1847 bytes |
| Load address: | 2B204556 |
| Exec address: | 44524148 |
Duplicates
There is 1 duplicate copy of this file in the archive:
- Personal collection » Acorn ADFS disks » Electron_User_Group » EUG_35.ADF » F/+HARD4
- Personal collection » Acorn hard disk » zipped_disks » elk03 » eug35/F/+HARD4
File contents
6. Cables, you will need the following cables:
1. 50 way to 50 way IDC to go from the host adaptor to
the disk controller (typically 6")
2. 34 way to 34 way IDC to go from the BBC's 1MHz bus to
host adaptor (typically 3')
3. 34 way IDC to 34 way edge connector for drive control
signals to controller card (typically 12")
If you are using a WD 1002 controller this is an edge
to edge connector lead
4. 20 way IDC to 20 way edge connector for drive data
signals to controller card (typically 12")
Using a Winchester on the Beeb has absolutely nothing to do with any
floppy disk controller that you may have fitted be it 8271, 1770 or any
other. If you have something other than a 1770 controller then you might
consider changing to one but it is not necessary. The BBC B+ and Master
have the 1770 fitted (or the 1772 which is similar), for the BBC B you can
fit the Acorn 1770 board or the Solidisk DDFS or DFDC boards (Issue 2).
The advantage of using the 1770 is that ADFS can work with it on floppies
as well as with the Winchester controller. For compatibility with the
older DFS's Acorn's 1770-DFS, or Solidisk's STL-DFS 2.2 can be used.
The layout of "drive numbers" under ADFS is as follows (when a Winchester
is fitted):
Drive Drive Handled Description
Number Letter by
0 A Controller 1st SASI device (LUN=0), 1st Winny
1 B Controller 2nd SASI device (LUN=1), 2nd Winny
2 C Controller 3rd SASI device
3 D Controller 4th SASI device
4 E 1770 First floppy
5 F 1770 Second floppy
6 G -
7 H -
(note a floppy drive under ADFS is a unit, not a surface like DFS, a drive
can have 1 or two sides and 40 or 80 tracks).
Basically references to "drive numbers" of 4 or higher are passed to code
within ADFS which uses the 1770/1772 controller chip in the Beeb/Master
and pretends to be a SASI compatible controller, while "drive numbers" of
0 to 3 are used to generate requests for I/O to a SASI device responding
to the equivalent LUN on one of the controller(s) connected (see
discussion of LUNs above).
The BBC micro/Master computers support Acorn's Winchester disk units,
which are connected via the 1MHz bus. The Advanced User Guide shows that
memory locations $FC40 to $FC47 are set aside for Winchester disk units
(these are located in page FRED).
A host adaptor on these machines requires 4 bytes of memory space, as 8
bytes are reserved it is believed that two controllers can be mapped on
to the system.
Two winchester drives have been used successfully on one controller, and
as expected they appear as drive 0 and 1. Unfortunately ADFS 1.30 on the
BBC B/B+ doesn't support a second host adaptor, probably because there was
not sufficient space in the ROM for the extra code, we can only hope that
Acorn will implement the extra code one day??? Note Sun,19 Apr 1987 :
Rumour has it Acorn are doing just that !
The memory map looks like this:
Controller Address Read Write
0 FC40 Data Data
FC41 Status -
FC42 - Select
FC43 - Interrupt latch
1 FC44 Data Data
FC45 Status -
FC46 - Select
FC47 - Interrupt latch
Providing you have your power supply, winchester drive, ADFS ROM,
controller card and cables, the sticking point is the host adaptor - the
host adaptor connects the standard SASI controller to the BBC, it sorts
out the addressing, buffering and inverts the data bus (SASI uses negative
logic).
Acorn do not sell parts of their Winchester disk system - you cannot buy
just the host adaptor. A number of other companies now sell complete
Winchester disk systems (Amcon, Viglen, Technomatic, Midwich etc.) they
have had to design and manufacture their own host adaptors, it is just
possible that they might sell the host adaptor separately. If they do
then it should cost you around, say, `50 maximum - any more would be
scandalous.
If you can't buy a host adaptor then you have to resort to building one...
the next part of this note deals with building a Host Adaptor. Fig. 1 is
the circuit diagram of a modified version of Acorn's host adaptor, it can
be built for around `35. Double sided PCBs are available from the author
for `15.00 plus `1.00 P&P, these boards are being made in small quantities
only, by hand, hence the price.
How it works
IC5 (74LS245), IC6 (74LS138) and IC7 (74LS138) perform the address line
buffering and decoding, S1 provides a link selectable setting for
controller 0 or controller 1 (base address FC40 or FC44). The output of
the address decoder provides eight lines (active low), four for read and
four for write (shown for controller 0 on the diagram).
IC1 (74LS245) buffers the data bus continuously, IC2 (73LS373) is used to
latch data that is written to the controller. Write data is inverted by
IC13/14 when enabled by the I/O control signal from the controller card.
IC13/14 (7438) are open collector output devices that drive the SASI data
port (pins 2 to 16).
Data is read from the controller card, inverted and buffered by IC3
(74LS240). Controller status is inverted by individual Schmitt inverters
in IC15 (7414) and latched and buffered by IC4 (74LS373). Acknowledge
(ACK) signals are provided automatically after a Request from the
controller when a read or write to the data port is performed. Select
(SEL) is driven automatically by the Busy (BSY) status from the
controller.
An unusual interrupt generating arrangement is also incorporated, a set
reset flip flop, IC12, is set every time a Request (REQ) is received from
the controller, and is cleared when a "1" is written to bit of the
interrupt latch, half of IC10. This allows interupts from the controller
to be ignored during block read/write operations but to be enabled during
byte read/write and provide the necessary handshaking between the host and
the controller.
The host adaptor connects to the 1MHz bus via a length of 34 way ribbon
cable and to the host adaptor via a length of 50 ribbon cable. IDC
connectors or cheaper pin headers (available from Farnell) may be used. A
power connector (similar to those used on floppy drives) is provided for
connection of +5v (no 12v supply is required). The power rails are
decoupled at every chip by small 0.1uF capacitors.
00000000 0d 36 2e 09 43 61 62 6c 65 73 2c 20 79 6f 75 20 |.6..Cables, you | 00000010 77 69 6c 6c 20 6e 65 65 64 20 74 68 65 20 66 6f |will need the fo| 00000020 6c 6c 6f 77 69 6e 67 20 63 61 62 6c 65 73 3a 0d |llowing cables:.| 00000030 0d 09 31 2e 09 35 30 20 77 61 79 20 74 6f 20 35 |..1..50 way to 5| 00000040 30 20 77 61 79 1a 20 49 44 43 1a 20 74 6f 1a 20 |0 way. IDC. to. | 00000050 67 6f 20 66 72 6f 6d 20 74 68 65 20 68 6f 73 74 |go from the host| 00000060 20 61 64 61 70 74 6f 72 20 74 6f 0d 09 09 74 68 | adaptor to...th| 00000070 65 20 64 69 73 6b 20 63 6f 6e 74 72 6f 6c 6c 65 |e disk controlle| 00000080 72 20 28 74 79 70 69 63 61 6c 6c 79 20 36 22 29 |r (typically 6")| 00000090 0d 0d 09 32 2e 09 33 34 20 77 61 79 20 74 6f 20 |...2..34 way to | 000000a0 33 34 20 77 61 79 1a 20 49 44 43 20 74 6f 20 67 |34 way. IDC to g| 000000b0 6f 20 66 72 6f 6d 20 74 68 65 20 42 42 43 27 73 |o from the BBC's| 000000c0 20 31 4d 48 7a 20 62 75 73 20 74 6f 0d 09 09 68 | 1MHz bus to...h| 000000d0 6f 73 74 20 61 64 61 70 74 6f 72 20 28 74 79 70 |ost adaptor (typ| 000000e0 69 63 61 6c 6c 79 20 33 27 29 0d 0d 09 33 2e 09 |ically 3')...3..| 000000f0 33 34 20 77 61 79 20 49 44 43 20 74 6f 20 33 34 |34 way IDC to 34| 00000100 1a 20 77 61 79 20 65 64 67 65 20 63 6f 6e 6e 65 |. way edge conne| 00000110 63 74 6f 72 20 66 6f 72 20 64 72 69 76 65 20 63 |ctor for drive c| 00000120 6f 6e 74 72 6f 6c 0d 09 09 73 69 67 6e 61 6c 73 |ontrol...signals| 00000130 20 74 6f 20 63 6f 6e 74 72 6f 6c 6c 65 72 20 63 | to controller c| 00000140 61 72 64 20 28 74 79 70 69 63 61 6c 6c 79 20 31 |ard (typically 1| 00000150 32 22 29 0d 20 20 20 20 20 20 20 20 20 20 20 20 |2"). | 00000160 20 20 20 49 66 20 79 6f 75 20 61 72 65 20 75 73 | If you are us| 00000170 69 6e 67 20 61 20 57 44 20 31 30 30 32 20 63 6f |ing a WD 1002 co| 00000180 6e 74 72 6f 6c 6c 65 72 20 74 68 69 73 20 69 73 |ntroller this is| 00000190 20 61 6e 20 65 64 67 65 0d 09 09 74 6f 20 65 64 | an edge...to ed| 000001a0 67 65 20 63 6f 6e 6e 65 63 74 6f 72 20 6c 65 61 |ge connector lea| 000001b0 64 0d 0d 09 34 2e 09 32 30 20 77 61 79 20 49 44 |d...4..20 way ID| 000001c0 43 20 74 6f 20 32 30 1a 20 77 61 79 1a 20 65 64 |C to 20. way. ed| 000001d0 67 65 1a 20 63 6f 6e 6e 65 63 74 6f 72 1a 20 66 |ge. connector. f| 000001e0 6f 72 20 64 72 69 76 65 20 64 61 74 61 0d 09 09 |or drive data...| 000001f0 73 69 67 6e 61 6c 73 20 74 6f 20 63 6f 6e 74 72 |signals to contr| 00000200 6f 6c 6c 65 72 20 63 61 72 64 20 28 74 79 70 69 |oller card (typi| 00000210 63 61 6c 6c 79 20 31 32 22 29 0d 0d 55 73 69 6e |cally 12")..Usin| 00000220 67 20 61 20 57 69 6e 63 68 65 73 74 65 72 20 6f |g a Winchester o| 00000230 6e 20 74 68 65 20 42 65 65 62 20 68 61 73 20 61 |n the Beeb has a| 00000240 62 73 6f 6c 75 74 65 6c 79 20 6e 6f 74 68 69 6e |bsolutely nothin| 00000250 67 20 74 6f 20 64 6f 20 77 69 74 68 20 61 6e 79 |g to do with any| 00000260 0d 66 6c 6f 70 70 79 20 64 69 73 6b 20 63 6f 6e |.floppy disk con| 00000270 74 72 6f 6c 6c 65 72 20 74 68 61 74 20 79 6f 75 |troller that you| 00000280 20 6d 61 79 20 68 61 76 65 20 66 69 74 74 65 64 | may have fitted| 00000290 20 62 65 20 69 74 20 38 32 37 31 2c 20 31 37 37 | be it 8271, 177| 000002a0 30 20 6f 72 20 61 6e 79 0d 6f 74 68 65 72 2e 20 |0 or any.other. | 000002b0 20 49 66 20 79 6f 75 20 68 61 76 65 20 73 6f 6d | If you have som| 000002c0 65 74 68 69 6e 67 20 6f 74 68 65 72 20 74 68 61 |ething other tha| 000002d0 6e 20 61 20 31 37 37 30 20 63 6f 6e 74 72 6f 6c |n a 1770 control| 000002e0 6c 65 72 20 74 68 65 6e 20 79 6f 75 20 6d 69 67 |ler then you mig| 000002f0 68 74 0d 63 6f 6e 73 69 64 65 72 20 63 68 61 6e |ht.consider chan| 00000300 67 69 6e 67 20 74 6f 20 6f 6e 65 20 62 75 74 20 |ging to one but | 00000310 69 74 20 69 73 20 6e 6f 74 20 6e 65 63 65 73 73 |it is not necess| 00000320 61 72 79 2e 20 20 54 68 65 20 42 42 43 20 42 2b |ary. The BBC B+| 00000330 20 61 6e 64 20 4d 61 73 74 65 72 0d 68 61 76 65 | and Master.have| 00000340 20 74 68 65 20 31 37 37 30 20 66 69 74 74 65 64 | the 1770 fitted| 00000350 20 28 6f 72 20 74 68 65 20 31 37 37 32 20 77 68 | (or the 1772 wh| 00000360 69 63 68 20 69 73 20 73 69 6d 69 6c 61 72 29 2c |ich is similar),| 00000370 20 66 6f 72 20 74 68 65 20 42 42 43 20 42 20 79 | for the BBC B y| 00000380 6f 75 20 63 61 6e 0d 66 69 74 20 74 68 65 20 41 |ou can.fit the A| 00000390 63 6f 72 6e 20 31 37 37 30 20 62 6f 61 72 64 20 |corn 1770 board | 000003a0 6f 72 20 74 68 65 20 53 6f 6c 69 64 69 73 6b 20 |or the Solidisk | 000003b0 44 44 46 53 20 6f 72 20 44 46 44 43 20 62 6f 61 |DDFS or DFDC boa| 000003c0 72 64 73 20 28 49 73 73 75 65 20 32 29 2e 20 0d |rds (Issue 2). .| 000003d0 54 68 65 20 61 64 76 61 6e 74 61 67 65 20 6f 66 |The advantage of| 000003e0 20 75 73 69 6e 67 20 74 68 65 20 31 37 37 30 20 | using the 1770 | 000003f0 69 73 20 74 68 61 74 20 41 44 46 53 20 63 61 6e |is that ADFS can| 00000400 20 77 6f 72 6b 20 77 69 74 68 20 69 74 20 6f 6e | work with it on| 00000410 20 66 6c 6f 70 70 69 65 73 0d 61 73 20 77 65 6c | floppies.as wel| 00000420 6c 20 61 73 20 77 69 74 68 20 74 68 65 20 57 69 |l as with the Wi| 00000430 6e 63 68 65 73 74 65 72 20 63 6f 6e 74 72 6f 6c |nchester control| 00000440 6c 65 72 2e 20 20 46 6f 72 20 63 6f 6d 70 61 74 |ler. For compat| 00000450 69 62 69 6c 69 74 79 20 77 69 74 68 20 74 68 65 |ibility with the| 00000460 0d 6f 6c 64 65 72 20 44 46 53 27 73 20 41 63 6f |.older DFS's Aco| 00000470 72 6e 27 73 20 31 37 37 30 2d 44 46 53 2c 20 6f |rn's 1770-DFS, o| 00000480 72 20 53 6f 6c 69 64 69 73 6b 27 73 20 53 54 4c |r Solidisk's STL| 00000490 2d 44 46 53 20 32 2e 32 20 63 61 6e 20 62 65 20 |-DFS 2.2 can be | 000004a0 75 73 65 64 2e 0d 0d 0d 54 68 65 20 6c 61 79 6f |used....The layo| 000004b0 75 74 20 6f 66 20 22 64 72 69 76 65 20 6e 75 6d |ut of "drive num| 000004c0 62 65 72 73 22 20 75 6e 64 65 72 20 41 44 46 53 |bers" under ADFS| 000004d0 20 69 73 20 61 73 20 66 6f 6c 6c 6f 77 73 20 28 | is as follows (| 000004e0 77 68 65 6e 20 61 20 57 69 6e 63 68 65 73 74 65 |when a Wincheste| 000004f0 72 0d 69 73 20 66 69 74 74 65 64 29 3a 0d 0d 44 |r.is fitted):..D| 00000500 72 69 76 65 09 44 72 69 76 65 09 48 61 6e 64 6c |rive.Drive.Handl| 00000510 65 64 09 09 44 65 73 63 72 69 70 74 69 6f 6e 0d |ed..Description.| 00000520 4e 75 6d 62 65 72 09 4c 65 74 74 65 72 09 62 79 |Number.Letter.by| 00000530 0d 0d 30 09 41 09 43 6f 6e 74 72 6f 6c 6c 65 72 |..0.A.Controller| 00000540 09 31 73 74 20 53 41 53 49 20 64 65 76 69 63 65 |.1st SASI device| 00000550 20 28 4c 55 4e 3d 30 29 2c 20 31 73 74 20 57 69 | (LUN=0), 1st Wi| 00000560 6e 6e 79 0d 31 09 42 09 43 6f 6e 74 72 6f 6c 6c |nny.1.B.Controll| 00000570 65 72 09 32 6e 64 20 53 41 53 49 20 64 65 76 69 |er.2nd SASI devi| 00000580 63 65 20 28 4c 55 4e 3d 31 29 2c 20 32 6e 64 20 |ce (LUN=1), 2nd | 00000590 57 69 6e 6e 79 0d 32 09 43 09 43 6f 6e 74 72 6f |Winny.2.C.Contro| 000005a0 6c 6c 65 72 09 33 72 64 20 53 41 53 49 20 64 65 |ller.3rd SASI de| 000005b0 76 69 63 65 0d 33 09 44 09 43 6f 6e 74 72 6f 6c |vice.3.D.Control| 000005c0 6c 65 72 09 34 74 68 20 53 41 53 49 20 64 65 76 |ler.4th SASI dev| 000005d0 69 63 65 0d 34 09 45 09 31 37 37 30 09 09 46 69 |ice.4.E.1770..Fi| 000005e0 72 73 74 20 66 6c 6f 70 70 79 0d 35 09 46 09 31 |rst floppy.5.F.1| 000005f0 37 37 30 09 09 53 65 63 6f 6e 64 20 66 6c 6f 70 |770..Second flop| 00000600 70 79 0d 36 09 47 09 2d 0d 37 09 48 09 2d 0d 0d |py.6.G.-.7.H.-..| 00000610 28 6e 6f 74 65 20 61 20 66 6c 6f 70 70 79 20 64 |(note a floppy d| 00000620 72 69 76 65 20 75 6e 64 65 72 20 41 44 46 53 20 |rive under ADFS | 00000630 69 73 20 61 20 75 6e 69 74 2c 20 6e 6f 74 20 61 |is a unit, not a| 00000640 20 73 75 72 66 61 63 65 20 6c 69 6b 65 20 44 46 | surface like DF| 00000650 53 2c 20 61 20 64 72 69 76 65 0d 63 61 6e 20 68 |S, a drive.can h| 00000660 61 76 65 20 31 20 6f 72 20 74 77 6f 20 73 69 64 |ave 1 or two sid| 00000670 65 73 20 61 6e 64 20 34 30 20 6f 72 20 38 30 20 |es and 40 or 80 | 00000680 74 72 61 63 6b 73 29 2e 0d 0d 42 61 73 69 63 61 |tracks)...Basica| 00000690 6c 6c 79 20 72 65 66 65 72 65 6e 63 65 73 20 74 |lly references t| 000006a0 6f 20 22 64 72 69 76 65 20 6e 75 6d 62 65 72 73 |o "drive numbers| 000006b0 22 20 6f 66 20 34 20 6f 72 20 68 69 67 68 65 72 |" of 4 or higher| 000006c0 20 61 72 65 20 70 61 73 73 65 64 20 74 6f 20 63 | are passed to c| 000006d0 6f 64 65 0d 77 69 74 68 69 6e 20 41 44 46 53 20 |ode.within ADFS | 000006e0 77 68 69 63 68 20 75 73 65 73 20 74 68 65 20 31 |which uses the 1| 000006f0 37 37 30 2f 31 37 37 32 20 63 6f 6e 74 72 6f 6c |770/1772 control| 00000700 6c 65 72 20 63 68 69 70 20 69 6e 20 74 68 65 20 |ler chip in the | 00000710 42 65 65 62 2f 4d 61 73 74 65 72 0d 61 6e 64 20 |Beeb/Master.and | 00000720 70 72 65 74 65 6e 64 73 20 74 6f 20 62 65 20 61 |pretends to be a| 00000730 20 53 41 53 49 20 63 6f 6d 70 61 74 69 62 6c 65 | SASI compatible| 00000740 20 63 6f 6e 74 72 6f 6c 6c 65 72 2c 20 77 68 69 | controller, whi| 00000750 6c 65 20 22 64 72 69 76 65 20 6e 75 6d 62 65 72 |le "drive number| 00000760 73 22 20 6f 66 0d 30 20 74 6f 20 33 20 61 72 65 |s" of.0 to 3 are| 00000770 20 75 73 65 64 20 74 6f 20 67 65 6e 65 72 61 74 | used to generat| 00000780 65 20 72 65 71 75 65 73 74 73 20 66 6f 72 20 49 |e requests for I| 00000790 2f 4f 20 74 6f 20 61 20 53 41 53 49 20 64 65 76 |/O to a SASI dev| 000007a0 69 63 65 20 72 65 73 70 6f 6e 64 69 6e 67 0d 74 |ice responding.t| 000007b0 6f 20 74 68 65 20 65 71 75 69 76 61 6c 65 6e 74 |o the equivalent| 000007c0 20 4c 55 4e 20 6f 6e 20 6f 6e 65 20 6f 66 20 74 | LUN on one of t| 000007d0 68 65 20 63 6f 6e 74 72 6f 6c 6c 65 72 28 73 29 |he controller(s)| 000007e0 20 63 6f 6e 6e 65 63 74 65 64 20 28 73 65 65 0d | connected (see.| 000007f0 64 69 73 63 75 73 73 69 6f 6e 20 6f 66 20 4c 55 |discussion of LU| 00000800 4e 73 20 61 62 6f 76 65 29 2e 0d 0d 54 68 65 20 |Ns above)...The | 00000810 42 42 43 20 6d 69 63 72 6f 2f 4d 61 73 74 65 72 |BBC micro/Master| 00000820 20 63 6f 6d 70 75 74 65 72 73 20 73 75 70 70 6f | computers suppo| 00000830 72 74 20 41 63 6f 72 6e 27 73 20 57 69 6e 63 68 |rt Acorn's Winch| 00000840 65 73 74 65 72 20 64 69 73 6b 20 75 6e 69 74 73 |ester disk units| 00000850 2c 0d 77 68 69 63 68 20 61 72 65 20 63 6f 6e 6e |,.which are conn| 00000860 65 63 74 65 64 20 76 69 61 20 74 68 65 20 31 4d |ected via the 1M| 00000870 48 7a 20 62 75 73 2e 20 20 54 68 65 20 41 64 76 |Hz bus. The Adv| 00000880 61 6e 63 65 64 20 55 73 65 72 20 47 75 69 64 65 |anced User Guide| 00000890 20 73 68 6f 77 73 20 74 68 61 74 0d 6d 65 6d 6f | shows that.memo| 000008a0 72 79 20 6c 6f 63 61 74 69 6f 6e 73 20 24 46 43 |ry locations $FC| 000008b0 34 30 20 74 6f 20 24 46 43 34 37 20 61 72 65 20 |40 to $FC47 are | 000008c0 73 65 74 20 61 73 69 64 65 20 66 6f 72 20 57 69 |set aside for Wi| 000008d0 6e 63 68 65 73 74 65 72 20 64 69 73 6b 20 75 6e |nchester disk un| 000008e0 69 74 73 0d 28 74 68 65 73 65 20 61 72 65 20 6c |its.(these are l| 000008f0 6f 63 61 74 65 64 20 69 6e 20 70 61 67 65 20 46 |ocated in page F| 00000900 52 45 44 29 2e 0d 0d 41 20 68 6f 73 74 20 61 64 |RED)...A host ad| 00000910 61 70 74 6f 72 20 6f 6e 20 74 68 65 73 65 20 6d |aptor on these m| 00000920 61 63 68 69 6e 65 73 20 72 65 71 75 69 72 65 73 |achines requires| 00000930 20 34 20 62 79 74 65 73 20 6f 66 20 6d 65 6d 6f | 4 bytes of memo| 00000940 72 79 20 73 70 61 63 65 2c 20 61 73 20 38 0d 62 |ry space, as 8.b| 00000950 79 74 65 73 20 61 72 65 20 72 65 73 65 72 76 65 |ytes are reserve| 00000960 64 20 69 74 20 69 73 20 62 65 6c 69 65 76 65 64 |d it is believed| 00000970 20 74 68 61 74 20 74 77 6f 20 63 6f 6e 74 72 6f | that two contro| 00000980 6c 6c 65 72 73 20 63 61 6e 20 62 65 20 6d 61 70 |llers can be map| 00000990 70 65 64 20 6f 6e 20 0d 74 6f 20 74 68 65 20 73 |ped on .to the s| 000009a0 79 73 74 65 6d 2e 0d 0d 54 77 6f 20 77 69 6e 63 |ystem...Two winc| 000009b0 68 65 73 74 65 72 20 64 72 69 76 65 73 20 68 61 |hester drives ha| 000009c0 76 65 20 62 65 65 6e 20 75 73 65 64 20 73 75 63 |ve been used suc| 000009d0 63 65 73 73 66 75 6c 6c 79 20 6f 6e 20 6f 6e 65 |cessfully on one| 000009e0 20 63 6f 6e 74 72 6f 6c 6c 65 72 2c 20 61 6e 64 | controller, and| 000009f0 0d 61 73 20 65 78 70 65 63 74 65 64 20 74 68 65 |.as expected the| 00000a00 79 20 61 70 70 65 61 72 20 61 73 20 64 72 69 76 |y appear as driv| 00000a10 65 20 30 20 61 6e 64 20 31 2e 20 20 55 6e 66 6f |e 0 and 1. Unfo| 00000a20 72 74 75 6e 61 74 65 6c 79 20 41 44 46 53 20 31 |rtunately ADFS 1| 00000a30 2e 33 30 20 6f 6e 20 74 68 65 0d 42 42 43 20 42 |.30 on the.BBC B| 00000a40 2f 42 2b 20 64 6f 65 73 6e 27 74 20 73 75 70 70 |/B+ doesn't supp| 00000a50 6f 72 74 20 61 20 73 65 63 6f 6e 64 20 68 6f 73 |ort a second hos| 00000a60 74 20 61 64 61 70 74 6f 72 2c 20 70 72 6f 62 61 |t adaptor, proba| 00000a70 62 6c 79 20 62 65 63 61 75 73 65 20 74 68 65 72 |bly because ther| 00000a80 65 20 77 61 73 0d 6e 6f 74 20 73 75 66 66 69 63 |e was.not suffic| 00000a90 69 65 6e 74 20 73 70 61 63 65 20 69 6e 20 74 68 |ient space in th| 00000aa0 65 20 52 4f 4d 20 66 6f 72 20 74 68 65 20 65 78 |e ROM for the ex| 00000ab0 74 72 61 20 63 6f 64 65 2c 20 77 65 20 63 61 6e |tra code, we can| 00000ac0 20 6f 6e 6c 79 20 68 6f 70 65 20 74 68 61 74 0d | only hope that.| 00000ad0 41 63 6f 72 6e 20 77 69 6c 6c 20 69 6d 70 6c 65 |Acorn will imple| 00000ae0 6d 65 6e 74 20 74 68 65 20 65 78 74 72 61 20 63 |ment the extra c| 00000af0 6f 64 65 20 6f 6e 65 20 64 61 79 3f 3f 3f 20 4e |ode one day??? N| 00000b00 6f 74 65 20 53 75 6e 2c 31 39 20 41 70 72 20 31 |ote Sun,19 Apr 1| 00000b10 39 38 37 20 3a 0d 52 75 6d 6f 75 72 20 68 61 73 |987 :.Rumour has| 00000b20 20 69 74 20 41 63 6f 72 6e 20 61 72 65 20 64 6f | it Acorn are do| 00000b30 69 6e 67 20 6a 75 73 74 20 74 68 61 74 20 21 0d |ing just that !.| 00000b40 0d 54 68 65 20 6d 65 6d 6f 72 79 20 6d 61 70 20 |.The memory map | 00000b50 6c 6f 6f 6b 73 20 6c 69 6b 65 20 74 68 69 73 3a |looks like this:| 00000b60 0d 0d 43 6f 6e 74 72 6f 6c 6c 65 72 09 41 64 64 |..Controller.Add| 00000b70 72 65 73 73 09 09 52 65 61 64 09 09 57 72 69 74 |ress..Read..Writ| 00000b80 65 0d 0d 30 09 09 46 43 34 30 09 09 44 61 74 61 |e..0..FC40..Data| 00000b90 09 09 44 61 74 61 0d 09 09 46 43 34 31 09 09 53 |..Data...FC41..S| 00000ba0 74 61 74 75 73 09 09 2d 0d 09 09 46 43 34 32 09 |tatus..-...FC42.| 00000bb0 09 2d 09 09 53 65 6c 65 63 74 0d 09 09 46 43 34 |.-..Select...FC4| 00000bc0 33 09 09 2d 09 09 49 6e 74 65 72 72 75 70 74 20 |3..-..Interrupt | 00000bd0 6c 61 74 63 68 0d 0d 31 09 09 46 43 34 34 09 09 |latch..1..FC44..| 00000be0 44 61 74 61 09 09 44 61 74 61 0d 09 09 46 43 34 |Data..Data...FC4| 00000bf0 35 09 09 53 74 61 74 75 73 09 09 2d 0d 09 09 46 |5..Status..-...F| 00000c00 43 34 36 09 09 2d 09 09 53 65 6c 65 63 74 0d 09 |C46..-..Select..| 00000c10 09 46 43 34 37 09 09 2d 09 09 49 6e 74 65 72 72 |.FC47..-..Interr| 00000c20 75 70 74 20 6c 61 74 63 68 0d 0d 0d 50 72 6f 76 |upt latch...Prov| 00000c30 69 64 69 6e 67 20 79 6f 75 20 68 61 76 65 20 79 |iding you have y| 00000c40 6f 75 72 20 70 6f 77 65 72 20 73 75 70 70 6c 79 |our power supply| 00000c50 2c 20 77 69 6e 63 68 65 73 74 65 72 20 64 72 69 |, winchester dri| 00000c60 76 65 2c 20 41 44 46 53 20 52 4f 4d 2c 0d 63 6f |ve, ADFS ROM,.co| 00000c70 6e 74 72 6f 6c 6c 65 72 20 63 61 72 64 20 61 6e |ntroller card an| 00000c80 64 20 63 61 62 6c 65 73 2c 20 74 68 65 20 73 74 |d cables, the st| 00000c90 69 63 6b 69 6e 67 20 70 6f 69 6e 74 20 69 73 20 |icking point is | 00000ca0 74 68 65 20 68 6f 73 74 20 61 64 61 70 74 6f 72 |the host adaptor| 00000cb0 20 2d 20 74 68 65 0d 68 6f 73 74 20 61 64 61 70 | - the.host adap| 00000cc0 74 6f 72 20 63 6f 6e 6e 65 63 74 73 20 74 68 65 |tor connects the| 00000cd0 20 73 74 61 6e 64 61 72 64 20 53 41 53 49 20 63 | standard SASI c| 00000ce0 6f 6e 74 72 6f 6c 6c 65 72 20 74 6f 20 74 68 65 |ontroller to the| 00000cf0 20 42 42 43 2c 20 69 74 20 73 6f 72 74 73 0d 6f | BBC, it sorts.o| 00000d00 75 74 20 74 68 65 20 61 64 64 72 65 73 73 69 6e |ut the addressin| 00000d10 67 2c 20 62 75 66 66 65 72 69 6e 67 20 61 6e 64 |g, buffering and| 00000d20 20 69 6e 76 65 72 74 73 20 74 68 65 20 64 61 74 | inverts the dat| 00000d30 61 20 62 75 73 20 28 53 41 53 49 20 75 73 65 73 |a bus (SASI uses| 00000d40 20 6e 65 67 61 74 69 76 65 0d 6c 6f 67 69 63 29 | negative.logic)| 00000d50 2e 0d 0d 41 63 6f 72 6e 20 64 6f 20 6e 6f 74 20 |...Acorn do not | 00000d60 73 65 6c 6c 20 70 61 72 74 73 20 6f 66 20 74 68 |sell parts of th| 00000d70 65 69 72 20 57 69 6e 63 68 65 73 74 65 72 20 64 |eir Winchester d| 00000d80 69 73 6b 20 73 79 73 74 65 6d 20 2d 20 79 6f 75 |isk system - you| 00000d90 20 63 61 6e 6e 6f 74 20 62 75 79 0d 6a 75 73 74 | cannot buy.just| 00000da0 20 74 68 65 20 68 6f 73 74 20 61 64 61 70 74 6f | the host adapto| 00000db0 72 2e 20 20 41 20 6e 75 6d 62 65 72 20 6f 66 20 |r. A number of | 00000dc0 6f 74 68 65 72 20 63 6f 6d 70 61 6e 69 65 73 20 |other companies | 00000dd0 6e 6f 77 20 73 65 6c 6c 20 63 6f 6d 70 6c 65 74 |now sell complet| 00000de0 65 0d 57 69 6e 63 68 65 73 74 65 72 20 64 69 73 |e.Winchester dis| 00000df0 6b 20 73 79 73 74 65 6d 73 20 28 41 6d 63 6f 6e |k systems (Amcon| 00000e00 2c 20 56 69 67 6c 65 6e 2c 20 54 65 63 68 6e 6f |, Viglen, Techno| 00000e10 6d 61 74 69 63 2c 20 4d 69 64 77 69 63 68 20 65 |matic, Midwich e| 00000e20 74 63 2e 29 20 74 68 65 79 0d 68 61 76 65 20 68 |tc.) they.have h| 00000e30 61 64 20 74 6f 20 64 65 73 69 67 6e 20 61 6e 64 |ad to design and| 00000e40 20 6d 61 6e 75 66 61 63 74 75 72 65 20 74 68 65 | manufacture the| 00000e50 69 72 20 6f 77 6e 20 68 6f 73 74 20 61 64 61 70 |ir own host adap| 00000e60 74 6f 72 73 2c 20 69 74 20 69 73 20 6a 75 73 74 |tors, it is just| 00000e70 0d 70 6f 73 73 69 62 6c 65 20 74 68 61 74 20 74 |.possible that t| 00000e80 68 65 79 20 6d 69 67 68 74 20 73 65 6c 6c 20 74 |hey might sell t| 00000e90 68 65 20 68 6f 73 74 20 61 64 61 70 74 6f 72 20 |he host adaptor | 00000ea0 73 65 70 61 72 61 74 65 6c 79 2e 20 20 49 66 20 |separately. If | 00000eb0 74 68 65 79 20 64 6f 0d 74 68 65 6e 20 69 74 20 |they do.then it | 00000ec0 73 68 6f 75 6c 64 20 63 6f 73 74 20 79 6f 75 20 |should cost you | 00000ed0 61 72 6f 75 6e 64 2c 20 73 61 79 2c 20 60 35 30 |around, say, `50| 00000ee0 20 6d 61 78 69 6d 75 6d 20 2d 20 61 6e 79 20 6d | maximum - any m| 00000ef0 6f 72 65 20 77 6f 75 6c 64 20 62 65 0d 73 63 61 |ore would be.sca| 00000f00 6e 64 61 6c 6f 75 73 2e 0d 0d 49 66 20 79 6f 75 |ndalous...If you| 00000f10 20 63 61 6e 27 74 20 62 75 79 20 61 20 68 6f 73 | can't buy a hos| 00000f20 74 20 61 64 61 70 74 6f 72 20 74 68 65 6e 20 79 |t adaptor then y| 00000f30 6f 75 20 68 61 76 65 20 74 6f 20 72 65 73 6f 72 |ou have to resor| 00000f40 74 20 74 6f 20 62 75 69 6c 64 69 6e 67 20 6f 6e |t to building on| 00000f50 65 2e 2e 2e 0d 74 68 65 20 6e 65 78 74 20 70 61 |e....the next pa| 00000f60 72 74 20 6f 66 20 74 68 69 73 20 6e 6f 74 65 20 |rt of this note | 00000f70 64 65 61 6c 73 20 77 69 74 68 20 62 75 69 6c 64 |deals with build| 00000f80 69 6e 67 20 61 20 48 6f 73 74 20 41 64 61 70 74 |ing a Host Adapt| 00000f90 6f 72 2e 20 20 46 69 67 2e 20 31 20 20 69 73 0d |or. Fig. 1 is.| 00000fa0 74 68 65 20 63 69 72 63 75 69 74 20 64 69 61 67 |the circuit diag| 00000fb0 72 61 6d 20 6f 66 20 61 20 6d 6f 64 69 66 69 65 |ram of a modifie| 00000fc0 64 20 76 65 72 73 69 6f 6e 20 6f 66 20 41 63 6f |d version of Aco| 00000fd0 72 6e 27 73 20 68 6f 73 74 20 61 64 61 70 74 6f |rn's host adapto| 00000fe0 72 2c 20 69 74 20 63 61 6e 0d 62 65 20 62 75 69 |r, it can.be bui| 00000ff0 6c 74 20 66 6f 72 20 61 72 6f 75 6e 64 20 60 33 |lt for around `3| 00001000 35 2e 20 20 44 6f 75 62 6c 65 20 73 69 64 65 64 |5. Double sided| 00001010 20 50 43 42 73 20 61 72 65 20 61 76 61 69 6c 61 | PCBs are availa| 00001020 62 6c 65 20 66 72 6f 6d 20 74 68 65 20 61 75 74 |ble from the aut| 00001030 68 6f 72 0d 66 6f 72 20 60 31 35 2e 30 30 20 70 |hor.for `15.00 p| 00001040 6c 75 73 20 60 31 2e 30 30 20 50 26 50 2c 20 74 |lus `1.00 P&P, t| 00001050 68 65 73 65 20 62 6f 61 72 64 73 20 61 72 65 20 |hese boards are | 00001060 62 65 69 6e 67 20 6d 61 64 65 20 69 6e 20 73 6d |being made in sm| 00001070 61 6c 6c 20 71 75 61 6e 74 69 74 69 65 73 0d 6f |all quantities.o| 00001080 6e 6c 79 2c 20 62 79 20 68 61 6e 64 2c 20 68 65 |nly, by hand, he| 00001090 6e 63 65 20 74 68 65 20 70 72 69 63 65 2e 0d 0d |nce the price...| 000010a0 48 6f 77 20 69 74 20 77 6f 72 6b 73 0d 0d 49 43 |How it works..IC| 000010b0 35 20 28 37 34 4c 53 32 34 35 29 2c 20 49 43 36 |5 (74LS245), IC6| 000010c0 20 28 37 34 4c 53 31 33 38 29 20 61 6e 64 20 49 | (74LS138) and I| 000010d0 43 37 20 28 37 34 4c 53 31 33 38 29 20 70 65 72 |C7 (74LS138) per| 000010e0 66 6f 72 6d 20 74 68 65 20 61 64 64 72 65 73 73 |form the address| 000010f0 20 6c 69 6e 65 0d 62 75 66 66 65 72 69 6e 67 20 | line.buffering | 00001100 61 6e 64 20 64 65 63 6f 64 69 6e 67 2c 20 53 31 |and decoding, S1| 00001110 20 70 72 6f 76 69 64 65 73 20 61 20 6c 69 6e 6b | provides a link| 00001120 20 73 65 6c 65 63 74 61 62 6c 65 20 73 65 74 74 | selectable sett| 00001130 69 6e 67 20 66 6f 72 0d 63 6f 6e 74 72 6f 6c 6c |ing for.controll| 00001140 65 72 20 30 20 6f 72 20 63 6f 6e 74 72 6f 6c 6c |er 0 or controll| 00001150 65 72 20 31 20 28 62 61 73 65 20 61 64 64 72 65 |er 1 (base addre| 00001160 73 73 20 46 43 34 30 20 6f 72 20 46 43 34 34 29 |ss FC40 or FC44)| 00001170 2e 20 20 54 68 65 20 6f 75 74 70 75 74 20 6f 66 |. The output of| 00001180 0d 74 68 65 20 61 64 64 72 65 73 73 20 64 65 63 |.the address dec| 00001190 6f 64 65 72 20 70 72 6f 76 69 64 65 73 20 65 69 |oder provides ei| 000011a0 67 68 74 20 6c 69 6e 65 73 20 28 61 63 74 69 76 |ght lines (activ| 000011b0 65 20 6c 6f 77 29 2c 20 66 6f 75 72 20 66 6f 72 |e low), four for| 000011c0 20 72 65 61 64 20 61 6e 64 0d 66 6f 75 72 20 66 | read and.four f| 000011d0 6f 72 20 77 72 69 74 65 20 28 73 68 6f 77 6e 20 |or write (shown | 000011e0 66 6f 72 20 63 6f 6e 74 72 6f 6c 6c 65 72 20 30 |for controller 0| 000011f0 20 6f 6e 20 74 68 65 20 64 69 61 67 72 61 6d 29 | on the diagram)| 00001200 2e 0d 0d 49 43 31 20 28 37 34 4c 53 32 34 35 29 |...IC1 (74LS245)| 00001210 20 62 75 66 66 65 72 73 20 74 68 65 20 64 61 74 | buffers the dat| 00001220 61 20 62 75 73 20 63 6f 6e 74 69 6e 75 6f 75 73 |a bus continuous| 00001230 6c 79 2c 20 49 43 32 20 28 37 33 4c 53 33 37 33 |ly, IC2 (73LS373| 00001240 29 20 69 73 20 75 73 65 64 20 74 6f 0d 6c 61 74 |) is used to.lat| 00001250 63 68 20 64 61 74 61 20 74 68 61 74 20 69 73 20 |ch data that is | 00001260 77 72 69 74 74 65 6e 20 74 6f 20 74 68 65 20 63 |written to the c| 00001270 6f 6e 74 72 6f 6c 6c 65 72 2e 20 20 57 72 69 74 |ontroller. Writ| 00001280 65 20 64 61 74 61 20 69 73 20 69 6e 76 65 72 74 |e data is invert| 00001290 65 64 20 62 79 0d 49 43 31 33 2f 31 34 20 77 68 |ed by.IC13/14 wh| 000012a0 65 6e 20 65 6e 61 62 6c 65 64 20 62 79 20 74 68 |en enabled by th| 000012b0 65 20 49 2f 4f 20 63 6f 6e 74 72 6f 6c 20 73 69 |e I/O control si| 000012c0 67 6e 61 6c 20 66 72 6f 6d 20 74 68 65 20 63 6f |gnal from the co| 000012d0 6e 74 72 6f 6c 6c 65 72 20 63 61 72 64 2e 20 0d |ntroller card. .| 000012e0 49 43 31 33 2f 31 34 20 28 37 34 33 38 29 20 61 |IC13/14 (7438) a| 000012f0 72 65 20 6f 70 65 6e 20 63 6f 6c 6c 65 63 74 6f |re open collecto| 00001300 72 20 6f 75 74 70 75 74 20 64 65 76 69 63 65 73 |r output devices| 00001310 20 74 68 61 74 20 64 72 69 76 65 20 74 68 65 20 | that drive the | 00001320 53 41 53 49 20 64 61 74 61 0d 70 6f 72 74 20 28 |SASI data.port (| 00001330 70 69 6e 73 20 32 20 74 6f 20 31 36 29 2e 0d 0d |pins 2 to 16)...| 00001340 44 61 74 61 20 69 73 20 72 65 61 64 20 66 72 6f |Data is read fro| 00001350 6d 20 74 68 65 20 63 6f 6e 74 72 6f 6c 6c 65 72 |m the controller| 00001360 20 63 61 72 64 2c 20 69 6e 76 65 72 74 65 64 20 | card, inverted | 00001370 61 6e 64 20 62 75 66 66 65 72 65 64 20 62 79 20 |and buffered by | 00001380 49 43 33 0d 28 37 34 4c 53 32 34 30 29 2e 20 20 |IC3.(74LS240). | 00001390 43 6f 6e 74 72 6f 6c 6c 65 72 20 73 74 61 74 75 |Controller statu| 000013a0 73 20 69 73 20 69 6e 76 65 72 74 65 64 20 62 79 |s is inverted by| 000013b0 20 69 6e 64 69 76 69 64 75 61 6c 20 53 63 68 6d | individual Schm| 000013c0 69 74 74 20 69 6e 76 65 72 74 65 72 73 0d 69 6e |itt inverters.in| 000013d0 20 49 43 31 35 20 28 37 34 31 34 29 20 61 6e 64 | IC15 (7414) and| 000013e0 20 6c 61 74 63 68 65 64 20 61 6e 64 20 62 75 66 | latched and buf| 000013f0 66 65 72 65 64 20 62 79 20 49 43 34 20 28 37 34 |fered by IC4 (74| 00001400 4c 53 33 37 33 29 2e 20 20 41 63 6b 6e 6f 77 6c |LS373). Acknowl| 00001410 65 64 67 65 0d 28 41 43 4b 29 20 73 69 67 6e 61 |edge.(ACK) signa| 00001420 6c 73 20 61 72 65 20 70 72 6f 76 69 64 65 64 20 |ls are provided | 00001430 61 75 74 6f 6d 61 74 69 63 61 6c 6c 79 20 61 66 |automatically af| 00001440 74 65 72 20 61 20 52 65 71 75 65 73 74 20 66 72 |ter a Request fr| 00001450 6f 6d 20 74 68 65 0d 63 6f 6e 74 72 6f 6c 6c 65 |om the.controlle| 00001460 72 20 77 68 65 6e 20 61 20 72 65 61 64 20 6f 72 |r when a read or| 00001470 20 77 72 69 74 65 20 74 6f 20 74 68 65 20 64 61 | write to the da| 00001480 74 61 20 70 6f 72 74 20 69 73 20 70 65 72 66 6f |ta port is perfo| 00001490 72 6d 65 64 2e 20 20 53 65 6c 65 63 74 0d 28 53 |rmed. Select.(S| 000014a0 45 4c 29 20 69 73 20 64 72 69 76 65 6e 20 61 75 |EL) is driven au| 000014b0 74 6f 6d 61 74 69 63 61 6c 6c 79 20 62 79 20 74 |tomatically by t| 000014c0 68 65 20 42 75 73 79 20 28 42 53 59 29 20 73 74 |he Busy (BSY) st| 000014d0 61 74 75 73 20 66 72 6f 6d 20 74 68 65 0d 63 6f |atus from the.co| 000014e0 6e 74 72 6f 6c 6c 65 72 2e 0d 0d 41 6e 20 75 6e |ntroller...An un| 000014f0 75 73 75 61 6c 20 69 6e 74 65 72 72 75 70 74 20 |usual interrupt | 00001500 67 65 6e 65 72 61 74 69 6e 67 20 61 72 72 61 6e |generating arran| 00001510 67 65 6d 65 6e 74 20 69 73 20 61 6c 73 6f 20 69 |gement is also i| 00001520 6e 63 6f 72 70 6f 72 61 74 65 64 2c 20 61 20 73 |ncorporated, a s| 00001530 65 74 0d 72 65 73 65 74 20 66 6c 69 70 20 66 6c |et.reset flip fl| 00001540 6f 70 2c 20 49 43 31 32 2c 20 69 73 20 73 65 74 |op, IC12, is set| 00001550 20 65 76 65 72 79 20 74 69 6d 65 20 61 20 52 65 | every time a Re| 00001560 71 75 65 73 74 20 28 52 45 51 29 20 69 73 20 72 |quest (REQ) is r| 00001570 65 63 65 69 76 65 64 20 66 72 6f 6d 0d 74 68 65 |eceived from.the| 00001580 20 63 6f 6e 74 72 6f 6c 6c 65 72 2c 20 61 6e 64 | controller, and| 00001590 20 69 73 20 63 6c 65 61 72 65 64 20 77 68 65 6e | is cleared when| 000015a0 20 61 20 22 31 22 20 69 73 20 77 72 69 74 74 65 | a "1" is writte| 000015b0 6e 20 74 6f 20 62 69 74 20 6f 66 20 74 68 65 0d |n to bit of the.| 000015c0 69 6e 74 65 72 72 75 70 74 20 6c 61 74 63 68 2c |interrupt latch,| 000015d0 20 68 61 6c 66 20 6f 66 20 49 43 31 30 2e 20 54 | half of IC10. T| 000015e0 68 69 73 20 61 6c 6c 6f 77 73 20 69 6e 74 65 72 |his allows inter| 000015f0 75 70 74 73 20 66 72 6f 6d 20 74 68 65 20 63 6f |upts from the co| 00001600 6e 74 72 6f 6c 6c 65 72 0d 74 6f 20 62 65 20 69 |ntroller.to be i| 00001610 67 6e 6f 72 65 64 20 64 75 72 69 6e 67 20 62 6c |gnored during bl| 00001620 6f 63 6b 20 72 65 61 64 2f 77 72 69 74 65 20 6f |ock read/write o| 00001630 70 65 72 61 74 69 6f 6e 73 20 62 75 74 20 74 6f |perations but to| 00001640 20 62 65 20 65 6e 61 62 6c 65 64 20 64 75 72 69 | be enabled duri| 00001650 6e 67 0d 62 79 74 65 20 72 65 61 64 2f 77 72 69 |ng.byte read/wri| 00001660 74 65 20 61 6e 64 20 70 72 6f 76 69 64 65 20 74 |te and provide t| 00001670 68 65 20 6e 65 63 65 73 73 61 72 79 20 68 61 6e |he necessary han| 00001680 64 73 68 61 6b 69 6e 67 20 62 65 74 77 65 65 6e |dshaking between| 00001690 20 74 68 65 20 68 6f 73 74 20 61 6e 64 0d 74 68 | the host and.th| 000016a0 65 20 63 6f 6e 74 72 6f 6c 6c 65 72 2e 0d 0d 54 |e controller...T| 000016b0 68 65 20 68 6f 73 74 20 61 64 61 70 74 6f 72 20 |he host adaptor | 000016c0 63 6f 6e 6e 65 63 74 73 20 74 6f 20 74 68 65 20 |connects to the | 000016d0 31 4d 48 7a 20 62 75 73 20 76 69 61 20 61 20 6c |1MHz bus via a l| 000016e0 65 6e 67 74 68 20 6f 66 20 33 34 20 77 61 79 20 |ength of 34 way | 000016f0 72 69 62 62 6f 6e 0d 63 61 62 6c 65 20 61 6e 64 |ribbon.cable and| 00001700 20 74 6f 20 74 68 65 20 68 6f 73 74 20 61 64 61 | to the host ada| 00001710 70 74 6f 72 20 76 69 61 20 61 20 6c 65 6e 67 74 |ptor via a lengt| 00001720 68 20 6f 66 20 35 30 20 72 69 62 62 6f 6e 20 63 |h of 50 ribbon c| 00001730 61 62 6c 65 2e 20 20 49 44 43 0d 63 6f 6e 6e 65 |able. IDC.conne| 00001740 63 74 6f 72 73 20 6f 72 20 63 68 65 61 70 65 72 |ctors or cheaper| 00001750 20 70 69 6e 20 68 65 61 64 65 72 73 20 28 61 76 | pin headers (av| 00001760 61 69 6c 61 62 6c 65 20 66 72 6f 6d 20 46 61 72 |ailable from Far| 00001770 6e 65 6c 6c 29 20 6d 61 79 20 62 65 20 75 73 65 |nell) may be use| 00001780 64 2e 20 20 41 0d 70 6f 77 65 72 20 63 6f 6e 6e |d. A.power conn| 00001790 65 63 74 6f 72 20 28 73 69 6d 69 6c 61 72 20 74 |ector (similar t| 000017a0 6f 20 74 68 6f 73 65 20 75 73 65 64 20 6f 6e 20 |o those used on | 000017b0 66 6c 6f 70 70 79 20 64 72 69 76 65 73 29 20 69 |floppy drives) i| 000017c0 73 20 70 72 6f 76 69 64 65 64 20 66 6f 72 0d 63 |s provided for.c| 000017d0 6f 6e 6e 65 63 74 69 6f 6e 20 6f 66 20 2b 35 76 |onnection of +5v| 000017e0 20 28 6e 6f 20 31 32 76 20 73 75 70 70 6c 79 20 | (no 12v supply | 000017f0 69 73 20 72 65 71 75 69 72 65 64 29 2e 20 20 54 |is required). T| 00001800 68 65 20 70 6f 77 65 72 20 72 61 69 6c 73 20 61 |he power rails a| 00001810 72 65 0d 64 65 63 6f 75 70 6c 65 64 20 61 74 20 |re.decoupled at | 00001820 65 76 65 72 79 20 63 68 69 70 20 62 79 20 73 6d |every chip by sm| 00001830 61 6c 6c 20 30 2e 31 75 46 20 63 61 70 61 63 69 |all 0.1uF capaci| 00001840 74 6f 72 73 2e 0d 0d |tors...| 00001847
F/+HARD4.m0
F/+HARD4.m1
F/+HARD4.m2
F/+HARD4.m4
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