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@ -301,8 +301,7 @@ The plan, again, is to mimic data coming in on the cassette port, but with the p
From Apple II Circuit Description by Winston Gaylor From Apple II Circuit Description by Winston Gaylor
©1983 by Howard and Sams & Co, Inc. ©1983 by Howard and Sams & Co, Inc.
Here's the source for those calls, again via Here's the source for those calls, again via https://github.com/cmosher01/Apple-II-Source/blob/master/src/system/monitor/common/cassette.m4
https://github.com/cmosher01/Apple-II-Source/blob/master/src/system/monitor/common/cassette.m4
TAPEOUT = $C020 TAPEOUT = $C020
TAPEIN = $C060 TAPEIN = $C060
@ -338,6 +337,7 @@ $C05C = set annunciator 2 = 0
Entry point at $34A. Received byte is returned in Accumulator Entry point at $34A. Received byte is returned in Accumulator
READCOMBINED READCOMBINED
034A- A2 09 LDX #$09 ; reading 8 bits requires 9 transitions. 034A- A2 09 LDX #$09 ; reading 8 bits requires 9 transitions.
034C- A9 00 LDA #$00 ; clear the accumulator 034C- A9 00 LDA #$00 ; clear the accumulator
034E- 85 EF STA $EF ; $EF is staging for received byte, set 0 034E- 85 EF STA $EF ; $EF is staging for received byte, set 0
@ -363,6 +363,7 @@ READCOMBINED
And a demo: this reads one byte from the AVR output buffer to the screen. It gets one byte at a time, triggered by a keypress. The AVR will need to be ready to send one byte at a time when it sees ANN2 go HIGH ("SEND BUFFER CONTENT" mode, set by sending $80 as the function switch first). And a demo: this reads one byte from the AVR output buffer to the screen. It gets one byte at a time, triggered by a keypress. The AVR will need to be ready to send one byte at a time when it sees ANN2 go HIGH ("SEND BUFFER CONTENT" mode, set by sending $80 as the function switch first).
GETBYTEONKEY GETBYTEONKEY
0800- 20 1B FD JSR $FD1B ; wait for keypress 0800- 20 1B FD JSR $FD1B ; wait for keypress
0803- 20 4A 03 JSR $034A ; READBYTE 0803- 20 4A 03 JSR $034A ; READBYTE
0806- 20 DA FD JSR $FDDA ; print hex to screen 0806- 20 DA FD JSR $FDDA ; print hex to screen
@ -378,9 +379,7 @@ The GP2IO then sends the requested number of bytes from its internal output buff
Here is a buffered I/O routine for minimally interactive data transmission between the Apple II and a serial device connected to the GP2IO. Here is a buffered I/O routine for minimally interactive data transmission between the Apple II and a serial device connected to the GP2IO.
0800- 20 4D 08 JSR $084D ; start by querying the buffer length - is there anything waiting? 0800- 20 4D 08 JSR $084D ; start by querying the buffer length - is there anything waiting? returns with buffer length in $08
; returns with buffer length in $08
0804- A9 80 LDA #$80 ; load control byte $80 "send buffer bytes" 0804- A9 80 LDA #$80 ; load control byte $80 "send buffer bytes"
0806- 20 03 03 JSR $0303 ; send control byte 0806- 20 03 03 JSR $0303 ; send control byte
0809- A5 08 LDA $08 ; load buffer length (or however much buffer you want sent) 0809- A5 08 LDA $08 ; load buffer length (or however much buffer you want sent)
@ -396,7 +395,9 @@ Here is a buffered I/O routine for minimally interactive data transmission betwe
0822- 20 8E FD JSR $FD8E ; last byte. print CF/LF 0822- 20 8E FD JSR $FD8E ; last byte. print CF/LF
0825- 60 RTS ; return 0825- 60 RTS ; return
GETLINE GETLINE
0826- 20 6A FD JSR $FD6A ; get line of input 0826- 20 6A FD JSR $FD6A ; get line of input
0829- 8A TXA ; get input length into Accumulator 0829- 8A TXA ; get input length into Accumulator
082A- 85 07 STA $07 ; put input length into $07 082A- 85 07 STA $07 ; put input length into $07