Home » Archimedes archive » Acorn User » AU 1998-12.adf » Regulars » RTR/SerialIO
RTR/SerialIO
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 » Archimedes archive » Acorn User » AU 1998-12.adf » Regulars |
| Filename: | RTR/SerialIO |
| Read OK: | ✔ |
| File size: | 11DB bytes |
| Load address: | 0000 |
| Exec address: | 0000 |
File contents
;Serial I/O User Port
;For an 10 MHz clock
;A0 - Serial out
;A1 - Serial in
;A2 - CTS allows serial input
;A3 - RTS output held until this is low
;A4 - I/O mode 0 = Input mode 1 = Output mode
;Note for 16F84 invert the state of the PWRTE
LIST P=16C84
C EQU 0
PCL EQU 2
Z EQU 2
PORTB EQU 6
PORTA EQU 5
TRISB EQU 86H
TRISA EQU 85H
EECON1 EQU 88H
EEDATA EQU 8
EEADR EQU 9
STATUS EQU 3
RP0 EQU 5
INC EQU 1
cts EQU 2
rts EQU 3
sBuf EQU 0ch ;Serial send buffer
Scount EQU 0dh ;Tempory Counter
Cdown EQU 0eh ;Time delay countdown
rBuf EQU 0fh ;Recieve buffer
;
ORG 0
GOTO Start
;Recieve a serial byte
Rx bcf PORTA,cts ;Allow for incomming data
movlw 8 ;Number of data bits to get
movwf Scount
Sb btfsc PORTA,1 ;Hold until start bit
goto Sb
bsf PORTA,cts ;Stop any more incomming
call hDelay ;Half a baud delay
Rnb bcf STATUS,C ;Clear the carry bit
rrf rBuf,f ;Prepare for next bit
call rDelay ;Full baud delay for recieve
btfsc PORTA,1 ;Test input
bsf rBuf,7 ;Set if needed
decfsz Scount,f ;See if finished
goto Rnb ;Round again if not
call rDelay ;Allow for stop bit to start
return
;Send a serial byte
Send btfsc PORTA,rts ;Only proceed when rts is low
goto Send
movlw 9 ;Number of data bits to send
movwf Scount
bcf PORTA,0 ;Start bit
call cDelay ;Extra delay compensation
Sloop call Delay
btfsc sBuf,0 ;Set the next bit
bsf PORTA,0
btfss sBuf,0
bcf PORTA,0
rrf sBuf,f ;Shift for next time
decfsz Scount,f
goto Sloop ;Round until finished
bsf PORTA,0 ;Stop bit
call cDelay ;Extra delay compensation
call Delay
call Delay
call cDelay ;For good measure
return
cDelay movlw 2 ;Small delay at end of send
movwf Cdown
goto Dloop
hDelay movlw 21 ;half delay for serial recieve 10MHz clock
movwf Cdown ; 19,200 Baud rate
goto Dloop
rDelay movlw 38 ;Delay for serial recieve 10MHz clock
movwf Cdown ; 19,200 Baud rate
goto Dloop
Delay movlw 39 ;Delay for serial send 10MHz clock
movwf Cdown ; 19,200 Baud rate
Dloop decfsz Cdown,f
goto Dloop
return
Start
BSF STATUS,RP0 ;SELECT REGISTER BANK 1
MOVLW 1Ah ;Bits 4,3 & 2 inputs
MOVWF TRISA^80H
BCF STATUS,RP0 ;SELECT REGISTER BANK 0
BTFSC PORTA,4 ;See if in input or output mode
GOTO InLoop
BSF STATUS,RP0 ;SELECT REGISTER BANK 1
MOVLW 0 ;All port B to outputs
MOVWF TRISB^80H
BCF STATUS,RP0 ;SELECT REGISTER BANK 0
BSF PORTA,0 ;Serial at Mark
BSF PORTA,cts ;CTS disabled
outMain
call Rx ;Get byte to output
movf rBuf,w ;Byte to send
movwf PORTB ;Output it
movf PORTB,w ;Get output state
movwf sBuf ;Ready to output it
call Send ;Send it back to computer
goto outMain
InLoop
BSF STATUS,RP0 ;SELECT REGISTER BANK 1
MOVLW 0ffh ;All port B to inputs
MOVWF TRISB^80H
BCF 1,7 ;Enable pull up resistors
BCF STATUS,RP0 ;SELECT REGISTER BANK 0
BSF PORTA,0 ;Serial at Mark
BSF PORTA,cts ;CTS disabled
inMain
call Rx ;Get byte to initiate read
movf PORTB,w ;Get input state
movwf sBuf ;Ready to output it
call Send ;Send it back to computer
goto inMain
end
00000000 20 3b 53 65 72 69 61 6c 20 49 2f 4f 20 55 73 65 | ;Serial I/O Use| 00000010 72 20 50 6f 72 74 0a 20 3b 46 6f 72 20 61 6e 20 |r Port. ;For an | 00000020 31 30 20 4d 48 7a 20 63 6c 6f 63 6b 0a 20 3b 41 |10 MHz clock. ;A| 00000030 30 20 2d 20 53 65 72 69 61 6c 20 6f 75 74 0a 20 |0 - Serial out. | 00000040 3b 41 31 20 2d 20 53 65 72 69 61 6c 20 69 6e 0a |;A1 - Serial in.| 00000050 20 3b 41 32 20 2d 20 43 54 53 20 61 6c 6c 6f 77 | ;A2 - CTS allow| 00000060 73 20 73 65 72 69 61 6c 20 69 6e 70 75 74 0a 20 |s serial input. | 00000070 3b 41 33 20 2d 20 52 54 53 20 6f 75 74 70 75 74 |;A3 - RTS output| 00000080 20 68 65 6c 64 20 75 6e 74 69 6c 20 74 68 69 73 | held until this| 00000090 20 69 73 20 6c 6f 77 0a 20 3b 41 34 20 2d 20 49 | is low. ;A4 - I| 000000a0 2f 4f 20 6d 6f 64 65 20 30 20 3d 20 49 6e 70 75 |/O mode 0 = Inpu| 000000b0 74 20 6d 6f 64 65 20 20 20 31 20 3d 20 4f 75 74 |t mode 1 = Out| 000000c0 70 75 74 20 6d 6f 64 65 0a 20 0a 20 3b 4e 6f 74 |put mode. . ;Not| 000000d0 65 20 66 6f 72 20 31 36 46 38 34 20 69 6e 76 65 |e for 16F84 inve| 000000e0 72 74 20 74 68 65 20 73 74 61 74 65 20 6f 66 20 |rt the state of | 000000f0 74 68 65 20 50 57 52 54 45 0a 20 20 20 20 20 20 |the PWRTE. | 00000100 4c 49 53 54 20 50 3d 31 36 43 38 34 0a 20 20 20 |LIST P=16C84. | 00000110 20 20 20 20 0a 20 0a 20 43 20 20 20 20 20 20 20 | . . C | 00000120 45 51 55 20 20 20 20 20 30 0a 20 50 43 4c 20 20 |EQU 0. PCL | 00000130 20 20 20 45 51 55 20 20 20 20 20 32 0a 20 5a 20 | EQU 2. Z | 00000140 20 20 20 20 20 20 45 51 55 20 20 20 20 20 32 0a | EQU 2.| 00000150 20 50 4f 52 54 42 20 20 20 45 51 55 20 20 20 20 | PORTB EQU | 00000160 20 36 0a 20 50 4f 52 54 41 20 20 20 45 51 55 20 | 6. PORTA EQU | 00000170 20 20 20 20 35 0a 20 54 52 49 53 42 20 20 20 45 | 5. TRISB E| 00000180 51 55 20 20 20 20 20 38 36 48 0a 20 54 52 49 53 |QU 86H. TRIS| 00000190 41 20 20 20 45 51 55 20 20 20 20 20 38 35 48 0a |A EQU 85H.| 000001a0 20 45 45 43 4f 4e 31 20 20 45 51 55 20 20 20 20 | EECON1 EQU | 000001b0 20 38 38 48 0a 20 45 45 44 41 54 41 20 20 45 51 | 88H. EEDATA EQ| 000001c0 55 20 20 20 20 20 38 0a 20 45 45 41 44 52 20 20 |U 8. EEADR | 000001d0 20 45 51 55 20 20 20 20 20 39 0a 20 53 54 41 54 | EQU 9. STAT| 000001e0 55 53 20 20 45 51 55 20 20 20 20 20 33 0a 20 52 |US EQU 3. R| 000001f0 50 30 20 20 20 20 20 45 51 55 20 20 20 20 20 35 |P0 EQU 5| 00000200 0a 20 49 4e 43 20 20 20 20 20 45 51 55 20 20 20 |. INC EQU | 00000210 20 20 31 0a 20 63 74 73 20 20 20 20 20 45 51 55 | 1. cts EQU| 00000220 20 20 20 20 20 32 0a 20 72 74 73 20 20 20 20 20 | 2. rts | 00000230 45 51 55 20 20 20 20 20 33 0a 20 73 42 75 66 20 |EQU 3. sBuf | 00000240 20 20 20 45 51 55 20 20 20 20 30 63 68 20 20 20 | EQU 0ch | 00000250 20 20 3b 53 65 72 69 61 6c 20 73 65 6e 64 20 62 | ;Serial send b| 00000260 75 66 66 65 72 0a 20 53 63 6f 75 6e 74 20 20 45 |uffer. Scount E| 00000270 51 55 20 20 20 20 30 64 68 20 20 20 20 20 3b 54 |QU 0dh ;T| 00000280 65 6d 70 6f 72 79 20 43 6f 75 6e 74 65 72 0a 20 |empory Counter. | 00000290 43 64 6f 77 6e 20 20 20 45 51 55 20 20 20 20 30 |Cdown EQU 0| 000002a0 65 68 20 20 20 20 20 3b 54 69 6d 65 20 64 65 6c |eh ;Time del| 000002b0 61 79 20 63 6f 75 6e 74 64 6f 77 6e 0a 20 72 42 |ay countdown. rB| 000002c0 75 66 20 20 20 20 45 51 55 20 20 20 20 30 66 68 |uf EQU 0fh| 000002d0 20 20 20 20 20 3b 52 65 63 69 65 76 65 20 62 75 | ;Recieve bu| 000002e0 66 66 65 72 0a 0a 3b 0a 20 20 20 4f 52 47 20 30 |ffer..;. ORG 0| 000002f0 0a 20 20 20 20 20 20 20 20 47 4f 54 4f 20 20 20 |. GOTO | 00000300 20 53 74 61 72 74 0a 20 20 20 20 20 20 20 20 0a | Start. .| 00000310 3b 52 65 63 69 65 76 65 20 61 20 73 65 72 69 61 |;Recieve a seria| 00000320 6c 20 62 79 74 65 0a 52 78 20 20 20 20 20 20 62 |l byte.Rx b| 00000330 63 66 20 20 20 20 20 50 4f 52 54 41 2c 63 74 73 |cf PORTA,cts| 00000340 20 20 20 20 20 20 20 3b 41 6c 6c 6f 77 20 66 6f | ;Allow fo| 00000350 72 20 69 6e 63 6f 6d 6d 69 6e 67 20 64 61 74 61 |r incomming data| 00000360 0a 20 20 20 20 20 20 20 20 6d 6f 76 6c 77 20 20 |. movlw | 00000370 20 38 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | 8 | 00000380 20 3b 4e 75 6d 62 65 72 20 6f 66 20 64 61 74 61 | ;Number of data| 00000390 20 62 69 74 73 20 74 6f 20 67 65 74 0a 20 20 20 | bits to get. | 000003a0 20 20 20 20 20 6d 6f 76 77 66 20 20 20 53 63 6f | movwf Sco| 000003b0 75 6e 74 0a 53 62 20 20 20 20 20 20 62 74 66 73 |unt.Sb btfs| 000003c0 63 20 20 20 50 4f 52 54 41 2c 31 20 20 20 20 20 |c PORTA,1 | 000003d0 20 20 20 20 3b 48 6f 6c 64 20 75 6e 74 69 6c 20 | ;Hold until | 000003e0 73 74 61 72 74 20 62 69 74 0a 20 20 20 20 20 20 |start bit. | 000003f0 20 20 67 6f 74 6f 20 20 20 20 53 62 0a 20 20 20 | goto Sb. | 00000400 20 20 20 20 20 62 73 66 20 20 20 20 20 50 4f 52 | bsf POR| 00000410 54 41 2c 63 74 73 20 20 20 20 20 20 20 3b 53 74 |TA,cts ;St| 00000420 6f 70 20 61 6e 79 20 6d 6f 72 65 20 69 6e 63 6f |op any more inco| 00000430 6d 6d 69 6e 67 0a 20 20 20 20 20 20 20 20 63 61 |mming. ca| 00000440 6c 6c 20 20 20 20 68 44 65 6c 61 79 20 20 20 20 |ll hDelay | 00000450 20 20 20 20 20 20 3b 48 61 6c 66 20 61 20 62 61 | ;Half a ba| 00000460 75 64 20 64 65 6c 61 79 0a 52 6e 62 20 20 20 20 |ud delay.Rnb | 00000470 20 62 63 66 20 20 20 20 20 53 54 41 54 55 53 2c | bcf STATUS,| 00000480 43 20 20 20 20 20 20 20 20 3b 43 6c 65 61 72 20 |C ;Clear | 00000490 74 68 65 20 63 61 72 72 79 20 62 69 74 0a 20 20 |the carry bit. | 000004a0 20 20 20 20 20 20 72 72 66 20 20 20 20 20 72 42 | rrf rB| 000004b0 75 66 2c 66 20 20 20 20 20 20 20 20 20 20 3b 50 |uf,f ;P| 000004c0 72 65 70 61 72 65 20 66 6f 72 20 6e 65 78 74 20 |repare for next | 000004d0 62 69 74 20 20 0a 20 20 20 20 20 20 20 20 63 61 |bit . ca| 000004e0 6c 6c 20 20 20 20 72 44 65 6c 61 79 20 20 20 20 |ll rDelay | 000004f0 20 20 20 20 20 20 3b 46 75 6c 6c 20 62 61 75 64 | ;Full baud| 00000500 20 64 65 6c 61 79 20 66 6f 72 20 72 65 63 69 65 | delay for recie| 00000510 76 65 0a 20 20 20 20 20 20 20 20 62 74 66 73 63 |ve. btfsc| 00000520 20 20 20 50 4f 52 54 41 2c 31 20 20 20 20 20 20 | PORTA,1 | 00000530 20 20 20 3b 54 65 73 74 20 69 6e 70 75 74 0a 20 | ;Test input. | 00000540 20 20 20 20 20 20 20 62 73 66 20 20 20 20 20 72 | bsf r| 00000550 42 75 66 2c 37 20 20 20 20 20 20 20 20 20 20 3b |Buf,7 ;| 00000560 53 65 74 20 69 66 20 6e 65 65 64 65 64 0a 20 20 |Set if needed. | 00000570 20 20 20 20 20 20 64 65 63 66 73 7a 20 20 53 63 | decfsz Sc| 00000580 6f 75 6e 74 2c 66 20 20 20 20 20 20 20 20 3b 53 |ount,f ;S| 00000590 65 65 20 69 66 20 66 69 6e 69 73 68 65 64 0a 20 |ee if finished. | 000005a0 20 20 20 20 20 20 20 67 6f 74 6f 20 20 20 20 52 | goto R| 000005b0 6e 62 20 20 20 20 20 20 20 20 20 20 20 20 20 3b |nb ;| 000005c0 52 6f 75 6e 64 20 61 67 61 69 6e 20 69 66 20 6e |Round again if n| 000005d0 6f 74 0a 20 20 20 20 20 20 20 20 63 61 6c 6c 20 |ot. call | 000005e0 20 20 20 72 44 65 6c 61 79 20 20 20 20 20 20 20 | rDelay | 000005f0 20 20 20 3b 41 6c 6c 6f 77 20 66 6f 72 20 73 74 | ;Allow for st| 00000600 6f 70 20 62 69 74 20 74 6f 20 73 74 61 72 74 0a |op bit to start.| 00000610 20 20 20 20 20 20 20 20 72 65 74 75 72 6e 0a 20 | return. | 00000620 20 20 20 20 20 20 20 0a 0a 3b 53 65 6e 64 20 61 | ..;Send a| 00000630 20 73 65 72 69 61 6c 20 62 79 74 65 0a 53 65 6e | serial byte.Sen| 00000640 64 20 20 20 20 62 74 66 73 63 20 20 20 50 4f 52 |d btfsc POR| 00000650 54 41 2c 72 74 73 20 20 20 20 20 20 20 3b 4f 6e |TA,rts ;On| 00000660 6c 79 20 70 72 6f 63 65 65 64 20 77 68 65 6e 20 |ly proceed when | 00000670 72 74 73 20 69 73 20 6c 6f 77 0a 20 20 20 20 20 |rts is low. | 00000680 20 20 20 67 6f 74 6f 20 20 20 20 53 65 6e 64 0a | goto Send.| 00000690 20 20 20 20 20 20 20 20 6d 6f 76 6c 77 20 20 20 | movlw | 000006a0 39 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 |9 | 000006b0 3b 4e 75 6d 62 65 72 20 6f 66 20 64 61 74 61 20 |;Number of data | 000006c0 62 69 74 73 20 74 6f 20 73 65 6e 64 0a 20 20 20 |bits to send. | 000006d0 20 20 20 20 20 6d 6f 76 77 66 20 20 20 53 63 6f | movwf Sco| 000006e0 75 6e 74 0a 20 20 20 20 20 20 20 20 62 63 66 20 |unt. bcf | 000006f0 20 20 20 20 50 4f 52 54 41 2c 30 20 20 20 20 20 | PORTA,0 | 00000700 20 20 20 20 3b 53 74 61 72 74 20 62 69 74 0a 20 | ;Start bit. | 00000710 20 20 20 20 20 20 20 63 61 6c 6c 20 20 20 20 63 | call c| 00000720 44 65 6c 61 79 20 20 20 20 20 20 20 20 20 20 3b |Delay ;| 00000730 45 78 74 72 61 20 64 65 6c 61 79 20 63 6f 6d 70 |Extra delay comp| 00000740 65 6e 73 61 74 69 6f 6e 0a 53 6c 6f 6f 70 20 20 |ensation.Sloop | 00000750 20 63 61 6c 6c 20 20 20 20 44 65 6c 61 79 0a 20 | call Delay. | 00000760 20 20 20 20 20 20 20 62 74 66 73 63 20 20 20 73 | btfsc s| 00000770 42 75 66 2c 30 20 20 20 20 20 20 20 20 20 20 3b |Buf,0 ;| 00000780 53 65 74 20 74 68 65 20 6e 65 78 74 20 62 69 74 |Set the next bit| 00000790 0a 20 20 20 20 20 20 20 20 62 73 66 20 20 20 20 |. bsf | 000007a0 20 50 4f 52 54 41 2c 30 0a 20 20 20 20 20 20 20 | PORTA,0. | 000007b0 20 62 74 66 73 73 20 20 20 73 42 75 66 2c 30 0a | btfss sBuf,0.| 000007c0 20 20 20 20 20 20 20 20 62 63 66 20 20 20 20 20 | bcf | 000007d0 50 4f 52 54 41 2c 30 0a 20 20 20 20 20 20 20 20 |PORTA,0. | 000007e0 72 72 66 20 20 20 20 20 73 42 75 66 2c 66 20 20 |rrf sBuf,f | 000007f0 20 20 20 20 20 20 20 20 3b 53 68 69 66 74 20 66 | ;Shift f| 00000800 6f 72 20 6e 65 78 74 20 74 69 6d 65 0a 20 20 20 |or next time. | 00000810 20 20 20 20 20 64 65 63 66 73 7a 20 20 53 63 6f | decfsz Sco| 00000820 75 6e 74 2c 66 0a 20 20 20 20 20 20 20 20 67 6f |unt,f. go| 00000830 74 6f 20 20 20 20 53 6c 6f 6f 70 20 20 20 20 20 |to Sloop | 00000840 20 20 20 20 20 20 3b 52 6f 75 6e 64 20 75 6e 74 | ;Round unt| 00000850 69 6c 20 66 69 6e 69 73 68 65 64 0a 20 20 20 20 |il finished. | 00000860 20 20 20 20 62 73 66 20 20 20 20 20 50 4f 52 54 | bsf PORT| 00000870 41 2c 30 20 20 20 20 20 20 20 20 20 3b 53 74 6f |A,0 ;Sto| 00000880 70 20 62 69 74 0a 20 20 20 20 20 20 20 20 63 61 |p bit. ca| 00000890 6c 6c 20 20 20 20 63 44 65 6c 61 79 20 20 20 20 |ll cDelay | 000008a0 20 20 20 20 20 20 3b 45 78 74 72 61 20 64 65 6c | ;Extra del| 000008b0 61 79 20 63 6f 6d 70 65 6e 73 61 74 69 6f 6e 0a |ay compensation.| 000008c0 20 20 20 20 20 20 20 20 63 61 6c 6c 20 20 20 20 | call | 000008d0 44 65 6c 61 79 0a 20 20 20 20 20 20 20 20 63 61 |Delay. ca| 000008e0 6c 6c 20 20 20 20 44 65 6c 61 79 0a 20 20 20 20 |ll Delay. | 000008f0 20 20 20 20 63 61 6c 6c 20 20 20 20 63 44 65 6c | call cDel| 00000900 61 79 20 20 20 20 20 20 20 20 20 20 3b 46 6f 72 |ay ;For| 00000910 20 67 6f 6f 64 20 6d 65 61 73 75 72 65 0a 20 20 | good measure. | 00000920 20 20 20 20 20 20 72 65 74 75 72 6e 0a 20 20 20 | return. | 00000930 20 20 20 20 20 0a 63 44 65 6c 61 79 20 20 6d 6f | .cDelay mo| 00000940 76 6c 77 20 20 20 32 20 20 20 20 20 20 20 20 20 |vlw 2 | 00000950 20 20 20 20 20 20 3b 53 6d 61 6c 6c 20 64 65 6c | ;Small del| 00000960 61 79 20 61 74 20 65 6e 64 20 6f 66 20 73 65 6e |ay at end of sen| 00000970 64 0a 20 20 20 20 20 20 20 20 6d 6f 76 77 66 20 |d. movwf | 00000980 20 20 43 64 6f 77 6e 20 20 20 20 20 20 20 20 20 | Cdown | 00000990 20 20 0a 20 20 20 20 20 20 20 20 67 6f 74 6f 20 | . goto | 000009a0 20 20 20 44 6c 6f 6f 70 0a 20 20 20 20 20 20 20 | Dloop. | 000009b0 20 0a 68 44 65 6c 61 79 20 20 6d 6f 76 6c 77 20 | .hDelay movlw | 000009c0 20 20 32 31 20 20 20 20 20 20 20 20 20 20 20 20 | 21 | 000009d0 20 20 3b 68 61 6c 66 20 64 65 6c 61 79 20 66 6f | ;half delay fo| 000009e0 72 20 73 65 72 69 61 6c 20 72 65 63 69 65 76 65 |r serial recieve| 000009f0 20 31 30 4d 48 7a 20 63 6c 6f 63 6b 0a 20 20 20 | 10MHz clock. | 00000a00 20 20 20 20 20 6d 6f 76 77 66 20 20 20 43 64 6f | movwf Cdo| 00000a10 77 6e 20 20 20 20 20 20 20 20 20 20 20 3b 20 31 |wn ; 1| 00000a20 39 2c 32 30 30 20 42 61 75 64 20 72 61 74 65 0a |9,200 Baud rate.| 00000a30 20 20 20 20 20 20 20 20 67 6f 74 6f 20 20 20 20 | goto | 00000a40 44 6c 6f 6f 70 0a 20 20 20 20 20 20 20 20 0a 72 |Dloop. .r| 00000a50 44 65 6c 61 79 20 20 6d 6f 76 6c 77 20 20 20 33 |Delay movlw 3| 00000a60 38 20 20 20 20 20 20 20 20 20 20 20 20 20 20 3b |8 ;| 00000a70 44 65 6c 61 79 20 66 6f 72 20 73 65 72 69 61 6c |Delay for serial| 00000a80 20 72 65 63 69 65 76 65 20 31 30 4d 48 7a 20 63 | recieve 10MHz c| 00000a90 6c 6f 63 6b 0a 20 20 20 20 20 20 20 20 6d 6f 76 |lock. mov| 00000aa0 77 66 20 20 20 43 64 6f 77 6e 20 20 20 20 20 20 |wf Cdown | 00000ab0 20 20 20 20 20 3b 20 31 39 2c 32 30 30 20 42 61 | ; 19,200 Ba| 00000ac0 75 64 20 72 61 74 65 0a 20 20 20 20 20 20 20 20 |ud rate. | 00000ad0 67 6f 74 6f 20 20 20 20 44 6c 6f 6f 70 0a 20 20 |goto Dloop. | 00000ae0 20 20 20 20 20 20 0a 44 65 6c 61 79 20 20 20 6d | .Delay m| 00000af0 6f 76 6c 77 20 20 20 33 39 20 20 20 20 20 20 20 |ovlw 39 | 00000b00 20 20 20 20 20 20 20 3b 44 65 6c 61 79 20 66 6f | ;Delay fo| 00000b10 72 20 73 65 72 69 61 6c 20 73 65 6e 64 20 31 30 |r serial send 10| 00000b20 4d 48 7a 20 63 6c 6f 63 6b 0a 20 20 20 20 20 20 |MHz clock. | 00000b30 20 20 6d 6f 76 77 66 20 20 20 43 64 6f 77 6e 20 | movwf Cdown | 00000b40 20 20 20 20 20 20 20 20 20 20 3b 20 31 39 2c 32 | ; 19,2| 00000b50 30 30 20 42 61 75 64 20 72 61 74 65 0a 44 6c 6f |00 Baud rate.Dlo| 00000b60 6f 70 20 20 20 64 65 63 66 73 7a 20 20 43 64 6f |op decfsz Cdo| 00000b70 77 6e 2c 66 0a 20 20 20 20 20 20 20 20 67 6f 74 |wn,f. got| 00000b80 6f 20 20 20 20 44 6c 6f 6f 70 0a 20 20 20 20 20 |o Dloop. | 00000b90 20 20 20 72 65 74 75 72 6e 0a 20 20 20 20 20 20 | return. | 00000ba0 20 20 0a 0a 53 74 61 72 74 0a 20 20 20 20 20 20 | ..Start. | 00000bb0 20 20 42 53 46 20 20 20 20 20 53 54 41 54 55 53 | BSF STATUS| 00000bc0 2c 52 50 30 20 20 20 20 20 20 3b 53 45 4c 45 43 |,RP0 ;SELEC| 00000bd0 54 20 52 45 47 49 53 54 45 52 20 42 41 4e 4b 20 |T REGISTER BANK | 00000be0 31 0a 20 20 20 20 20 20 20 20 4d 4f 56 4c 57 20 |1. MOVLW | 00000bf0 20 20 31 41 68 20 20 20 20 20 20 20 20 20 20 20 | 1Ah | 00000c00 20 20 3b 42 69 74 73 20 34 2c 33 20 26 20 32 20 | ;Bits 4,3 & 2 | 00000c10 69 6e 70 75 74 73 0a 20 20 20 20 20 20 20 20 4d |inputs. M| 00000c20 4f 56 57 46 20 20 20 54 52 49 53 41 5e 38 30 48 |OVWF TRISA^80H| 00000c30 0a 20 20 20 20 20 20 20 20 42 43 46 20 20 20 20 |. BCF | 00000c40 20 53 54 41 54 55 53 2c 52 50 30 20 20 20 20 20 | STATUS,RP0 | 00000c50 20 3b 53 45 4c 45 43 54 20 52 45 47 49 53 54 45 | ;SELECT REGISTE| 00000c60 52 20 42 41 4e 4b 20 30 0a 20 20 20 20 20 20 20 |R BANK 0. | 00000c70 20 42 54 46 53 43 20 20 20 50 4f 52 54 41 2c 34 | BTFSC PORTA,4| 00000c80 20 20 20 20 20 20 20 20 20 3b 53 65 65 20 69 66 | ;See if| 00000c90 20 69 6e 20 69 6e 70 75 74 20 6f 72 20 6f 75 74 | in input or out| 00000ca0 70 75 74 20 6d 6f 64 65 0a 20 20 20 20 20 20 20 |put mode. | 00000cb0 20 47 4f 54 4f 20 20 20 20 49 6e 4c 6f 6f 70 0a | GOTO InLoop.| 00000cc0 20 20 20 20 20 20 20 20 0a 20 20 20 20 20 20 20 | . | 00000cd0 20 42 53 46 20 20 20 20 20 53 54 41 54 55 53 2c | BSF STATUS,| 00000ce0 52 50 30 20 20 20 20 20 20 3b 53 45 4c 45 43 54 |RP0 ;SELECT| 00000cf0 20 52 45 47 49 53 54 45 52 20 42 41 4e 4b 20 31 | REGISTER BANK 1| 00000d00 0a 20 20 20 20 20 20 20 20 4d 4f 56 4c 57 20 20 |. MOVLW | 00000d10 20 30 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | 0 | 00000d20 20 3b 41 6c 6c 20 70 6f 72 74 20 42 20 74 6f 20 | ;All port B to | 00000d30 6f 75 74 70 75 74 73 0a 20 20 20 20 20 20 20 20 |outputs. | 00000d40 4d 4f 56 57 46 20 20 20 54 52 49 53 42 5e 38 30 |MOVWF TRISB^80| 00000d50 48 0a 20 20 20 20 20 20 20 20 42 43 46 20 20 20 |H. BCF | 00000d60 20 20 53 54 41 54 55 53 2c 52 50 30 20 20 20 20 | STATUS,RP0 | 00000d70 20 20 3b 53 45 4c 45 43 54 20 52 45 47 49 53 54 | ;SELECT REGIST| 00000d80 45 52 20 42 41 4e 4b 20 30 0a 20 20 20 20 20 20 |ER BANK 0. | 00000d90 20 20 0a 20 20 20 20 20 20 20 20 42 53 46 20 20 | . BSF | 00000da0 20 20 20 50 4f 52 54 41 2c 30 20 20 20 20 20 20 | PORTA,0 | 00000db0 20 20 20 3b 53 65 72 69 61 6c 20 61 74 20 4d 61 | ;Serial at Ma| 00000dc0 72 6b 0a 20 20 20 20 20 20 20 20 42 53 46 20 20 |rk. BSF | 00000dd0 20 20 20 50 4f 52 54 41 2c 63 74 73 20 20 20 20 | PORTA,cts | 00000de0 20 20 20 3b 43 54 53 20 64 69 73 61 62 6c 65 64 | ;CTS disabled| 00000df0 0a 20 20 20 20 20 20 20 20 20 20 0a 0a 6f 75 74 |. ..out| 00000e00 4d 61 69 6e 0a 20 20 20 20 20 20 63 61 6c 6c 20 |Main. call | 00000e10 20 20 20 20 20 52 78 20 20 20 20 20 20 20 20 20 | Rx | 00000e20 20 20 20 20 20 3b 47 65 74 20 62 79 74 65 20 74 | ;Get byte t| 00000e30 6f 20 6f 75 74 70 75 74 0a 20 20 20 20 20 20 6d |o output. m| 00000e40 6f 76 66 20 20 20 20 20 20 72 42 75 66 2c 77 20 |ovf rBuf,w | 00000e50 20 20 20 20 20 20 20 20 20 3b 42 79 74 65 20 74 | ;Byte t| 00000e60 6f 20 73 65 6e 64 0a 20 20 20 20 20 20 6d 6f 76 |o send. mov| 00000e70 77 66 20 20 20 20 20 50 4f 52 54 42 20 20 20 20 |wf PORTB | 00000e80 20 20 20 20 20 20 20 3b 4f 75 74 70 75 74 20 69 | ;Output i| 00000e90 74 0a 20 20 20 20 20 20 6d 6f 76 66 20 20 20 20 |t. movf | 00000ea0 20 20 50 4f 52 54 42 2c 77 20 20 20 20 20 20 20 | PORTB,w | 00000eb0 20 20 3b 47 65 74 20 6f 75 74 70 75 74 20 73 74 | ;Get output st| 00000ec0 61 74 65 0a 20 20 20 20 20 20 6d 6f 76 77 66 20 |ate. movwf | 00000ed0 20 20 20 20 73 42 75 66 20 20 20 20 20 20 20 20 | sBuf | 00000ee0 20 20 20 20 3b 52 65 61 64 79 20 74 6f 20 6f 75 | ;Ready to ou| 00000ef0 74 70 75 74 20 69 74 0a 20 20 20 20 20 20 63 61 |tput it. ca| 00000f00 6c 6c 20 20 20 20 20 20 53 65 6e 64 20 20 20 20 |ll Send | 00000f10 20 20 20 20 20 20 20 20 3b 53 65 6e 64 20 69 74 | ;Send it| 00000f20 20 62 61 63 6b 20 74 6f 20 63 6f 6d 70 75 74 65 | back to compute| 00000f30 72 0a 20 20 20 20 20 20 67 6f 74 6f 20 20 20 20 |r. goto | 00000f40 20 20 6f 75 74 4d 61 69 6e 0a 0a 49 6e 4c 6f 6f | outMain..InLoo| 00000f50 70 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 |p | 00000f60 0a 20 20 20 20 20 20 20 42 53 46 20 20 20 20 20 |. BSF | 00000f70 53 54 41 54 55 53 2c 52 50 30 20 20 20 20 20 20 |STATUS,RP0 | 00000f80 3b 53 45 4c 45 43 54 20 52 45 47 49 53 54 45 52 |;SELECT REGISTER| 00000f90 20 42 41 4e 4b 20 31 0a 20 20 20 20 20 20 20 4d | BANK 1. M| 00000fa0 4f 56 4c 57 20 20 20 30 66 66 68 20 20 20 20 20 |OVLW 0ffh | 00000fb0 20 20 20 20 20 20 20 3b 41 6c 6c 20 70 6f 72 74 | ;All port| 00000fc0 20 42 20 74 6f 20 69 6e 70 75 74 73 0a 20 20 20 | B to inputs. | 00000fd0 20 20 20 20 4d 4f 56 57 46 20 20 20 54 52 49 53 | MOVWF TRIS| 00000fe0 42 5e 38 30 48 0a 20 20 20 20 20 20 20 42 43 46 |B^80H. BCF| 00000ff0 20 20 20 20 20 31 2c 37 20 20 20 20 20 20 20 20 | 1,7 | 00001000 20 20 20 20 20 3b 45 6e 61 62 6c 65 20 70 75 6c | ;Enable pul| 00001010 6c 20 75 70 20 72 65 73 69 73 74 6f 72 73 0a 20 |l up resistors. | 00001020 20 20 20 20 20 20 42 43 46 20 20 20 20 20 53 54 | BCF ST| 00001030 41 54 55 53 2c 52 50 30 20 20 20 20 20 20 3b 53 |ATUS,RP0 ;S| 00001040 45 4c 45 43 54 20 52 45 47 49 53 54 45 52 20 42 |ELECT REGISTER B| 00001050 41 4e 4b 20 30 0a 20 20 20 20 20 20 20 20 0a 20 |ANK 0. . | 00001060 20 20 20 20 20 20 42 53 46 20 20 20 20 20 50 4f | BSF PO| 00001070 52 54 41 2c 30 20 20 20 20 20 20 20 20 20 3b 53 |RTA,0 ;S| 00001080 65 72 69 61 6c 20 61 74 20 4d 61 72 6b 0a 20 20 |erial at Mark. | 00001090 20 20 20 20 20 42 53 46 20 20 20 20 20 50 4f 52 | BSF POR| 000010a0 54 41 2c 63 74 73 20 20 20 20 20 20 20 3b 43 54 |TA,cts ;CT| 000010b0 53 20 64 69 73 61 62 6c 65 64 0a 20 20 20 20 20 |S disabled. | 000010c0 20 20 20 20 20 0a 0a 69 6e 4d 61 69 6e 0a 20 20 | ..inMain. | 000010d0 20 20 20 20 63 61 6c 6c 20 20 20 20 20 20 52 78 | call Rx| 000010e0 20 20 20 20 20 20 20 20 20 20 20 20 20 20 3b 47 | ;G| 000010f0 65 74 20 62 79 74 65 20 74 6f 20 69 6e 69 74 69 |et byte to initi| 00001100 61 74 65 20 72 65 61 64 0a 20 20 20 20 20 20 6d |ate read. m| 00001110 6f 76 66 20 20 20 20 20 20 50 4f 52 54 42 2c 77 |ovf PORTB,w| 00001120 20 20 20 20 20 20 20 20 20 3b 47 65 74 20 69 6e | ;Get in| 00001130 70 75 74 20 73 74 61 74 65 0a 20 20 20 20 20 20 |put state. | 00001140 6d 6f 76 77 66 20 20 20 20 20 73 42 75 66 20 20 |movwf sBuf | 00001150 20 20 20 20 20 20 20 20 20 20 3b 52 65 61 64 79 | ;Ready| 00001160 20 74 6f 20 6f 75 74 70 75 74 20 69 74 0a 20 20 | to output it. | 00001170 20 20 20 20 63 61 6c 6c 20 20 20 20 20 20 53 65 | call Se| 00001180 6e 64 20 20 20 20 20 20 20 20 20 20 20 20 3b 53 |nd ;S| 00001190 65 6e 64 20 69 74 20 62 61 63 6b 20 74 6f 20 63 |end it back to c| 000011a0 6f 6d 70 75 74 65 72 0a 20 20 20 20 20 20 67 6f |omputer. go| 000011b0 74 6f 20 20 20 20 20 20 69 6e 4d 61 69 6e 0a 20 |to inMain. | 000011c0 20 20 20 20 20 20 20 65 6e 64 20 20 20 20 20 20 | end | 000011d0 20 20 20 20 20 20 20 20 20 20 0a | .| 000011db
.