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/*
Copyright (C) 1998, 1999 by Denis Chertykov (denisc@overta.ru)
You can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
This function send one byte to PC parallel port.
Connect AVR with parallel port
AVR Parallel Port
Signal name Pin Pin Signal name
GND 20 ------------ 19 GND
GND 20 ------------ 21 GND
SCK 8 ------------ 1 Strobe
MOSI 6 ------------ 12 Out of paper
MISO 7 ------------ 11 Busy
Reset 9 ------------ 16 Init
Connect parallel port pin 12 with parallel port pin 2 through diod
Out of paper 12 ----|>|--- 2 Data 0
This connection allow to use send_byte and program AVR flash
with Uros Platise `uisp' in dummy mode.
Bugs: For me this work only if Parellel port in EPP mode.
May be ECP mode also work ?
*/
/* #arch AT90S8515 */
#define PORTB $18
#define DDRB $17
#define PINB $16
seg removable flash.code.send_byte
public _send_byte:
mov r24,r25
ldi r25,0x55
rcall send_byte1
mov r25,r24
send_byte1:
ldi r19,8
send_bloop:
mov r21,r25
andi r21,1
ldi r21,0x20+0x40
breq send_bz
ldi r21,0x20
send_bz:
in r20,PORTB
or r20,r21
out PORTB,r20
send_bwait_z:
in r18, PINB
andi r18, 0x80
breq send_bwait_z
andi r20,0x9f
out PORTB,r20
nnm: in r18, PINB
andi r18, 0x80
brne nnm
asr r25
dec r19
brne send_bloop
ret
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