Home » Personal collection » Acorn ADFS disks » Electron_User_Group » EUG_33.ADF » F/+DISA1
F/+DISA1
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_33.ADF |
| Filename: | F/+DISA1 |
| Read OK: | ✔ |
| File size: | 0B0A bytes |
| Load address: | 0000 |
| Exec address: | 0000 |
File contents
Disabler Instructions ===================== If there is some gadget or add on that you wish to have control over but don't want to waste the user port or clog up a ROM socket then this simple circuit is ideal for you. It can be used to turn on/off any device (up to the rating of the transistor) including mains appliances (via a relay) such as a monitor,or used to supply logic levels to elsewhere on the board.This might,for example be used to control the READ lines on a block of sideways RAM to remove it from memory if a bad image has been loaded. The board will be activated by <BREAK><key> combination in a similar way to the disc filing system being booted. PARTS... The circuit diagram shows electronically how to assemble the device,requiring the following parts: 1x 74LS32 or equiv. (OR) 1x 74LS00 or equiv. (NAND) 1x 10 micro Farad capacitor or near match 1x 3.3k pull up resistor 1x 4.7k limiting resistor 1x NPN transistor to suit use (eg.ZTX300) Stripboard,wire,solder BENEFITS... *No additional driving software required *Easy to fit *No loss of valuable user port or other IO space (so no address decoding reqd) *Load needn't be on the +5v rail as shown in the diagram,any other (even external) PSU will do. BUILD... 1.Assemble the parts as efficiently as needed to fit onto the board you have.It is in fact sufficiently simple to use point to point wiring and a bit of insulation tape! 2.The +5v and 0v required by the logic can be taken from anywhere on the main board where it is present.Noteably the fly leads from the PSU or on pin 14 and 7 (respectively) of MOST logic chips. 3.Solder a wire to the not RST of the BREAK key on the keyboard 4.Solder the terminals marked 'A' and 'B' onto the chosen key combination. 5.Connect up the load as appropriate.The supply can be ANY dc supply,as long as its ground is common to the BBC's ground rail. 6.The capacitor and 3.3k resistor are needed to ensure a KNOWN reset condition occurs on powering up the BBC.Theie values AREN'T critical. HINTS... *I used this to turn off a fan that I added to my machine,where the supply of the fan was taken from the 12v line inside the PSU that is usually used for the disc drive *By the addition of more OR gates (there are still 2 spare inside the LS32) you can make it into a <BREAK><key><key><key> combination if you have enough fingers to press all the buttons! *In its present state the transistor is on by default on power up.ie.the output of the RS latch made by the LS00 is high by default.If this is not as desired then swap it for the other output of the LS00 *Try swapping the RS latch for a divide by 2 counter,to give whatever it is you're controlling a toggling action FROM... Robert Sprowson. Happy soldering!
00000000 44 69 73 61 62 6c 65 72 20 49 6e 73 74 72 75 63 |Disabler Instruc| 00000010 74 69 6f 6e 73 0a 0d 3d 3d 3d 3d 3d 3d 3d 3d 3d |tions..=========| 00000020 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 0a 0d 49 66 |============..If| 00000030 20 74 68 65 72 65 20 69 73 20 73 6f 6d 65 20 67 | there is some g| 00000040 61 64 67 65 74 20 6f 72 20 61 64 64 20 6f 6e 20 |adget or add on | 00000050 74 68 61 74 20 79 6f 75 20 77 69 73 68 20 74 6f |that you wish to| 00000060 20 68 61 76 65 20 63 6f 6e 74 72 6f 6c 20 6f 76 | have control ov| 00000070 65 72 20 62 75 74 20 64 6f 6e 27 74 0a 0d 77 61 |er but don't..wa| 00000080 6e 74 20 74 6f 20 77 61 73 74 65 20 74 68 65 20 |nt to waste the | 00000090 75 73 65 72 20 70 6f 72 74 20 6f 72 20 63 6c 6f |user port or clo| 000000a0 67 20 75 70 20 61 20 52 4f 4d 20 73 6f 63 6b 65 |g up a ROM socke| 000000b0 74 20 74 68 65 6e 20 74 68 69 73 20 73 69 6d 70 |t then this simp| 000000c0 6c 65 20 63 69 72 63 75 69 74 0a 0d 69 73 20 69 |le circuit..is i| 000000d0 64 65 61 6c 20 66 6f 72 20 79 6f 75 2e 0a 0d 0a |deal for you....| 000000e0 0d 49 74 20 63 61 6e 20 62 65 20 75 73 65 64 20 |.It can be used | 000000f0 74 6f 20 74 75 72 6e 20 6f 6e 2f 6f 66 66 20 61 |to turn on/off a| 00000100 6e 79 20 64 65 76 69 63 65 20 28 75 70 20 74 6f |ny device (up to| 00000110 20 74 68 65 20 72 61 74 69 6e 67 20 6f 66 20 74 | the rating of t| 00000120 68 65 20 74 72 61 6e 73 69 73 74 6f 72 29 0a 0d |he transistor)..| 00000130 69 6e 63 6c 75 64 69 6e 67 20 6d 61 69 6e 73 20 |including mains | 00000140 61 70 70 6c 69 61 6e 63 65 73 20 28 76 69 61 20 |appliances (via | 00000150 61 20 72 65 6c 61 79 29 20 73 75 63 68 20 61 73 |a relay) such as| 00000160 20 61 20 6d 6f 6e 69 74 6f 72 2c 6f 72 20 75 73 | a monitor,or us| 00000170 65 64 20 74 6f 20 73 75 70 70 6c 79 0a 0d 6c 6f |ed to supply..lo| 00000180 67 69 63 20 6c 65 76 65 6c 73 20 74 6f 20 65 6c |gic levels to el| 00000190 73 65 77 68 65 72 65 20 6f 6e 20 74 68 65 20 62 |sewhere on the b| 000001a0 6f 61 72 64 2e 54 68 69 73 20 6d 69 67 68 74 2c |oard.This might,| 000001b0 66 6f 72 20 65 78 61 6d 70 6c 65 20 62 65 20 75 |for example be u| 000001c0 73 65 64 20 74 6f 20 0a 0d 63 6f 6e 74 72 6f 6c |sed to ..control| 000001d0 20 74 68 65 20 52 45 41 44 20 6c 69 6e 65 73 20 | the READ lines | 000001e0 6f 6e 20 61 20 62 6c 6f 63 6b 20 6f 66 20 73 69 |on a block of si| 000001f0 64 65 77 61 79 73 20 52 41 4d 20 74 6f 20 72 65 |deways RAM to re| 00000200 6d 6f 76 65 20 69 74 20 66 72 6f 6d 20 6d 65 6d |move it from mem| 00000210 6f 72 79 0a 0d 69 66 20 61 20 62 61 64 20 69 6d |ory..if a bad im| 00000220 61 67 65 20 68 61 73 20 62 65 65 6e 20 6c 6f 61 |age has been loa| 00000230 64 65 64 2e 0a 0d 0a 0d 54 68 65 20 62 6f 61 72 |ded.....The boar| 00000240 64 20 77 69 6c 6c 20 62 65 20 61 63 74 69 76 61 |d will be activa| 00000250 74 65 64 20 62 79 20 3c 42 52 45 41 4b 3e 3c 6b |ted by <BREAK><k| 00000260 65 79 3e 20 63 6f 6d 62 69 6e 61 74 69 6f 6e 20 |ey> combination | 00000270 69 6e 20 61 20 73 69 6d 69 6c 61 72 20 77 61 79 |in a similar way| 00000280 20 74 6f 0a 0d 74 68 65 20 64 69 73 63 20 66 69 | to..the disc fi| 00000290 6c 69 6e 67 20 73 79 73 74 65 6d 20 62 65 69 6e |ling system bein| 000002a0 67 20 62 6f 6f 74 65 64 2e 0a 0d 0a 0d 50 41 52 |g booted.....PAR| 000002b0 54 53 2e 2e 2e 0a 0d 54 68 65 20 63 69 72 63 75 |TS.....The circu| 000002c0 69 74 20 64 69 61 67 72 61 6d 20 73 68 6f 77 73 |it diagram shows| 000002d0 20 65 6c 65 63 74 72 6f 6e 69 63 61 6c 6c 79 20 | electronically | 000002e0 68 6f 77 20 74 6f 20 61 73 73 65 6d 62 6c 65 20 |how to assemble | 000002f0 74 68 65 20 64 65 76 69 63 65 2c 72 65 71 75 69 |the device,requi| 00000300 72 69 6e 67 0a 0d 74 68 65 20 66 6f 6c 6c 6f 77 |ring..the follow| 00000310 69 6e 67 20 70 61 72 74 73 3a 0a 0d 31 78 20 20 |ing parts:..1x | 00000320 37 34 4c 53 33 32 20 6f 72 20 65 71 75 69 76 2e |74LS32 or equiv.| 00000330 20 28 4f 52 29 0a 0d 31 78 20 20 37 34 4c 53 30 | (OR)..1x 74LS0| 00000340 30 20 6f 72 20 65 71 75 69 76 2e 20 28 4e 41 4e |0 or equiv. (NAN| 00000350 44 29 0a 0d 31 78 20 20 31 30 20 6d 69 63 72 6f |D)..1x 10 micro| 00000360 20 46 61 72 61 64 20 63 61 70 61 63 69 74 6f 72 | Farad capacitor| 00000370 20 6f 72 20 6e 65 61 72 20 6d 61 74 63 68 0a 0d | or near match..| 00000380 31 78 20 20 33 2e 33 6b 20 70 75 6c 6c 20 75 70 |1x 3.3k pull up| 00000390 20 72 65 73 69 73 74 6f 72 0a 0d 31 78 20 20 34 | resistor..1x 4| 000003a0 2e 37 6b 20 6c 69 6d 69 74 69 6e 67 20 72 65 73 |.7k limiting res| 000003b0 69 73 74 6f 72 0a 0d 31 78 20 20 4e 50 4e 20 74 |istor..1x NPN t| 000003c0 72 61 6e 73 69 73 74 6f 72 20 74 6f 20 73 75 69 |ransistor to sui| 000003d0 74 20 75 73 65 20 28 65 67 2e 5a 54 58 33 30 30 |t use (eg.ZTX300| 000003e0 29 0a 0d 53 74 72 69 70 62 6f 61 72 64 2c 77 69 |)..Stripboard,wi| 000003f0 72 65 2c 73 6f 6c 64 65 72 0a 0d 0a 0d 42 45 4e |re,solder....BEN| 00000400 45 46 49 54 53 2e 2e 2e 0a 0d 2a 4e 6f 20 61 64 |EFITS.....*No ad| 00000410 64 69 74 69 6f 6e 61 6c 20 64 72 69 76 69 6e 67 |ditional driving| 00000420 20 73 6f 66 74 77 61 72 65 20 72 65 71 75 69 72 | software requir| 00000430 65 64 0a 0d 2a 45 61 73 79 20 74 6f 20 66 69 74 |ed..*Easy to fit| 00000440 0a 0d 2a 4e 6f 20 6c 6f 73 73 20 6f 66 20 76 61 |..*No loss of va| 00000450 6c 75 61 62 6c 65 20 75 73 65 72 20 70 6f 72 74 |luable user port| 00000460 20 6f 72 20 6f 74 68 65 72 20 49 4f 20 73 70 61 | or other IO spa| 00000470 63 65 20 28 73 6f 20 6e 6f 20 61 64 64 72 65 73 |ce (so no addres| 00000480 73 20 64 65 63 6f 64 69 6e 67 20 72 65 71 64 29 |s decoding reqd)| 00000490 0a 0d 2a 4c 6f 61 64 20 6e 65 65 64 6e 27 74 20 |..*Load needn't | 000004a0 62 65 20 6f 6e 20 74 68 65 20 2b 35 76 20 72 61 |be on the +5v ra| 000004b0 69 6c 20 61 73 20 73 68 6f 77 6e 20 69 6e 20 74 |il as shown in t| 000004c0 68 65 20 64 69 61 67 72 61 6d 2c 61 6e 79 20 6f |he diagram,any o| 000004d0 74 68 65 72 20 28 65 76 65 6e 0a 0d 20 65 78 74 |ther (even.. ext| 000004e0 65 72 6e 61 6c 29 20 50 53 55 20 77 69 6c 6c 20 |ernal) PSU will | 000004f0 64 6f 2e 0a 0d 0a 0d 42 55 49 4c 44 2e 2e 2e 0a |do.....BUILD....| 00000500 0d 31 2e 41 73 73 65 6d 62 6c 65 20 74 68 65 20 |.1.Assemble the | 00000510 70 61 72 74 73 20 61 73 20 65 66 66 69 63 69 65 |parts as efficie| 00000520 6e 74 6c 79 20 61 73 20 6e 65 65 64 65 64 20 74 |ntly as needed t| 00000530 6f 20 66 69 74 20 6f 6e 74 6f 20 74 68 65 20 62 |o fit onto the b| 00000540 6f 61 72 64 20 79 6f 75 20 68 61 76 65 2e 49 74 |oard you have.It| 00000550 0a 0d 20 20 69 73 20 69 6e 20 66 61 63 74 20 73 |.. is in fact s| 00000560 75 66 66 69 63 69 65 6e 74 6c 79 20 73 69 6d 70 |ufficiently simp| 00000570 6c 65 20 74 6f 20 75 73 65 20 70 6f 69 6e 74 20 |le to use point | 00000580 74 6f 20 70 6f 69 6e 74 20 77 69 72 69 6e 67 20 |to point wiring | 00000590 61 6e 64 20 61 20 62 69 74 20 6f 66 0a 0d 20 20 |and a bit of.. | 000005a0 69 6e 73 75 6c 61 74 69 6f 6e 20 74 61 70 65 21 |insulation tape!| 000005b0 0a 0d 32 2e 54 68 65 20 2b 35 76 20 61 6e 64 20 |..2.The +5v and | 000005c0 30 76 20 72 65 71 75 69 72 65 64 20 62 79 20 74 |0v required by t| 000005d0 68 65 20 6c 6f 67 69 63 20 63 61 6e 20 62 65 20 |he logic can be | 000005e0 74 61 6b 65 6e 20 66 72 6f 6d 20 61 6e 79 77 68 |taken from anywh| 000005f0 65 72 65 20 6f 6e 20 74 68 65 20 6d 61 69 6e 0a |ere on the main.| 00000600 0d 20 20 62 6f 61 72 64 20 77 68 65 72 65 20 69 |. board where i| 00000610 74 20 69 73 20 70 72 65 73 65 6e 74 2e 4e 6f 74 |t is present.Not| 00000620 65 61 62 6c 79 20 74 68 65 20 66 6c 79 20 6c 65 |eably the fly le| 00000630 61 64 73 20 66 72 6f 6d 20 74 68 65 20 50 53 55 |ads from the PSU| 00000640 20 6f 72 20 6f 6e 20 70 69 6e 20 31 34 0a 0d 20 | or on pin 14.. | 00000650 20 61 6e 64 20 37 20 28 72 65 73 70 65 63 74 69 | and 7 (respecti| 00000660 76 65 6c 79 29 20 6f 66 20 4d 4f 53 54 20 6c 6f |vely) of MOST lo| 00000670 67 69 63 20 63 68 69 70 73 2e 0a 0d 33 2e 53 6f |gic chips...3.So| 00000680 6c 64 65 72 20 61 20 77 69 72 65 20 74 6f 20 74 |lder a wire to t| 00000690 68 65 20 6e 6f 74 20 52 53 54 20 6f 66 20 74 68 |he not RST of th| 000006a0 65 20 42 52 45 41 4b 20 6b 65 79 20 6f 6e 20 74 |e BREAK key on t| 000006b0 68 65 20 6b 65 79 62 6f 61 72 64 0a 0d 34 2e 53 |he keyboard..4.S| 000006c0 6f 6c 64 65 72 20 74 68 65 20 74 65 72 6d 69 6e |older the termin| 000006d0 61 6c 73 20 6d 61 72 6b 65 64 20 27 41 27 20 61 |als marked 'A' a| 000006e0 6e 64 20 27 42 27 20 6f 6e 74 6f 20 74 68 65 20 |nd 'B' onto the | 000006f0 63 68 6f 73 65 6e 20 6b 65 79 20 63 6f 6d 62 69 |chosen key combi| 00000700 6e 61 74 69 6f 6e 2e 0a 0d 35 2e 43 6f 6e 6e 65 |nation...5.Conne| 00000710 63 74 20 75 70 20 74 68 65 20 6c 6f 61 64 20 61 |ct up the load a| 00000720 73 20 61 70 70 72 6f 70 72 69 61 74 65 2e 54 68 |s appropriate.Th| 00000730 65 20 73 75 70 70 6c 79 20 63 61 6e 20 62 65 20 |e supply can be | 00000740 41 4e 59 20 64 63 20 73 75 70 70 6c 79 2c 61 73 |ANY dc supply,as| 00000750 20 6c 6f 6e 67 0a 0d 20 20 61 73 20 69 74 73 20 | long.. as its | 00000760 67 72 6f 75 6e 64 20 69 73 20 63 6f 6d 6d 6f 6e |ground is common| 00000770 20 74 6f 20 74 68 65 20 42 42 43 27 73 20 67 72 | to the BBC's gr| 00000780 6f 75 6e 64 20 72 61 69 6c 2e 0a 0d 36 2e 54 68 |ound rail...6.Th| 00000790 65 20 63 61 70 61 63 69 74 6f 72 20 61 6e 64 20 |e capacitor and | 000007a0 33 2e 33 6b 20 72 65 73 69 73 74 6f 72 20 61 72 |3.3k resistor ar| 000007b0 65 20 6e 65 65 64 65 64 20 74 6f 20 65 6e 73 75 |e needed to ensu| 000007c0 72 65 20 61 20 4b 4e 4f 57 4e 20 72 65 73 65 74 |re a KNOWN reset| 000007d0 20 63 6f 6e 64 69 74 69 6f 6e 0a 0d 20 20 6f 63 | condition.. oc| 000007e0 63 75 72 73 20 6f 6e 20 70 6f 77 65 72 69 6e 67 |curs on powering| 000007f0 20 75 70 20 74 68 65 20 42 42 43 2e 54 68 65 69 | up the BBC.Thei| 00000800 65 20 76 61 6c 75 65 73 20 41 52 45 4e 27 54 20 |e values AREN'T | 00000810 63 72 69 74 69 63 61 6c 2e 0a 0d 0a 0d 48 49 4e |critical.....HIN| 00000820 54 53 2e 2e 2e 0a 0d 2a 49 20 75 73 65 64 20 74 |TS.....*I used t| 00000830 68 69 73 20 74 6f 20 74 75 72 6e 20 6f 66 66 20 |his to turn off | 00000840 61 20 66 61 6e 20 74 68 61 74 20 49 20 61 64 64 |a fan that I add| 00000850 65 64 20 74 6f 20 6d 79 20 6d 61 63 68 69 6e 65 |ed to my machine| 00000860 2c 77 68 65 72 65 20 74 68 65 20 73 75 70 70 6c |,where the suppl| 00000870 79 20 6f 66 0a 0d 20 74 68 65 20 66 61 6e 20 77 |y of.. the fan w| 00000880 61 73 20 74 61 6b 65 6e 20 66 72 6f 6d 20 74 68 |as taken from th| 00000890 65 20 31 32 76 20 6c 69 6e 65 20 69 6e 73 69 64 |e 12v line insid| 000008a0 65 20 74 68 65 20 50 53 55 20 74 68 61 74 20 69 |e the PSU that i| 000008b0 73 20 75 73 75 61 6c 6c 79 20 75 73 65 64 20 66 |s usually used f| 000008c0 6f 72 0a 0d 20 74 68 65 20 64 69 73 63 20 64 72 |or.. the disc dr| 000008d0 69 76 65 0a 0d 2a 42 79 20 74 68 65 20 61 64 64 |ive..*By the add| 000008e0 69 74 69 6f 6e 20 6f 66 20 6d 6f 72 65 20 4f 52 |ition of more OR| 000008f0 20 67 61 74 65 73 20 28 74 68 65 72 65 20 61 72 | gates (there ar| 00000900 65 20 73 74 69 6c 6c 20 32 20 73 70 61 72 65 20 |e still 2 spare | 00000910 69 6e 73 69 64 65 20 74 68 65 20 4c 53 33 32 29 |inside the LS32)| 00000920 0a 0d 20 79 6f 75 20 63 61 6e 20 6d 61 6b 65 20 |.. you can make | 00000930 69 74 20 69 6e 74 6f 20 61 20 3c 42 52 45 41 4b |it into a <BREAK| 00000940 3e 3c 6b 65 79 3e 3c 6b 65 79 3e 3c 6b 65 79 3e |><key><key><key>| 00000950 20 63 6f 6d 62 69 6e 61 74 69 6f 6e 20 69 66 20 | combination if | 00000960 79 6f 75 20 68 61 76 65 20 65 6e 6f 75 67 68 0a |you have enough.| 00000970 0d 20 66 69 6e 67 65 72 73 20 74 6f 20 70 72 65 |. fingers to pre| 00000980 73 73 20 61 6c 6c 20 74 68 65 20 62 75 74 74 6f |ss all the butto| 00000990 6e 73 21 0a 0d 2a 49 6e 20 69 74 73 20 70 72 65 |ns!..*In its pre| 000009a0 73 65 6e 74 20 73 74 61 74 65 20 74 68 65 20 74 |sent state the t| 000009b0 72 61 6e 73 69 73 74 6f 72 20 69 73 20 6f 6e 20 |ransistor is on | 000009c0 62 79 20 64 65 66 61 75 6c 74 20 6f 6e 20 70 6f |by default on po| 000009d0 77 65 72 20 75 70 2e 69 65 2e 74 68 65 20 6f 75 |wer up.ie.the ou| 000009e0 74 70 75 74 0a 0d 20 6f 66 20 74 68 65 20 52 53 |tput.. of the RS| 000009f0 20 6c 61 74 63 68 20 6d 61 64 65 20 62 79 20 74 | latch made by t| 00000a00 68 65 20 4c 53 30 30 20 69 73 20 68 69 67 68 20 |he LS00 is high | 00000a10 62 79 20 64 65 66 61 75 6c 74 2e 49 66 20 74 68 |by default.If th| 00000a20 69 73 20 69 73 20 6e 6f 74 20 61 73 20 64 65 73 |is is not as des| 00000a30 69 72 65 64 0a 0d 20 74 68 65 6e 20 73 77 61 70 |ired.. then swap| 00000a40 20 69 74 20 66 6f 72 20 74 68 65 20 6f 74 68 65 | it for the othe| 00000a50 72 20 6f 75 74 70 75 74 20 6f 66 20 74 68 65 20 |r output of the | 00000a60 4c 53 30 30 0a 0d 2a 54 72 79 20 73 77 61 70 70 |LS00..*Try swapp| 00000a70 69 6e 67 20 74 68 65 20 52 53 20 6c 61 74 63 68 |ing the RS latch| 00000a80 20 66 6f 72 20 61 20 64 69 76 69 64 65 20 62 79 | for a divide by| 00000a90 20 32 20 63 6f 75 6e 74 65 72 2c 74 6f 20 67 69 | 2 counter,to gi| 00000aa0 76 65 20 77 68 61 74 65 76 65 72 20 69 74 20 69 |ve whatever it i| 00000ab0 73 20 0a 0d 20 79 6f 75 27 72 65 20 63 6f 6e 74 |s .. you're cont| 00000ac0 72 6f 6c 6c 69 6e 67 20 61 20 74 6f 67 67 6c 69 |rolling a toggli| 00000ad0 6e 67 20 61 63 74 69 6f 6e 0a 0d 0a 0d 46 52 4f |ng action....FRO| 00000ae0 4d 2e 2e 2e 0a 0d 52 6f 62 65 72 74 20 53 70 72 |M.....Robert Spr| 00000af0 6f 77 73 6f 6e 2e 0a 0d 48 61 70 70 79 20 73 6f |owson...Happy so| 00000b00 6c 64 65 72 69 6e 67 21 0a 0d |ldering!..| 00000b0a
F/+DISA1.m0
F/+DISA1.m1
F/+DISA1.m2
F/+DISA1.m4
F/+DISA1.m5
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