Files
aqhomecontrol/avr/modules/comproto/msg_twi.asm
2023-04-22 00:23:44 +02:00

68 lines
1.9 KiB
NASM

; ***************************************************************************
; copyright : (C) 2023 by Martin Preuss
; email : martin@libchipcard.de
;
; ***************************************************************************
; * This file is part of the project "AqHome". *
; * Please see toplevel file COPYING of that project for license details. *
; ***************************************************************************
; ***************************************************************************
; code
.cseg
; ---------------------------------------------------------------------------
; Enqueue a TWI Bus Member packet.
;
; IN:
; - R16: destination address
; - R1 : Address of the bus member
; - R2 : availability (0=not available, 1=available)
; OUT:
; - CFLAG: set if okay, clear otherwise
; MODIFIED REGS: R16, R17, R20, X (R15, Y)
CPRO_EnqueueTwiBusMember:
push r16
rcall COM_AllocBufferAndGetXY ; (r16, r17, r21)
pop r16
brcc CPRO_EnqueueTwiBusMember_error
clr r17 ; r17: XOR byte
; write header (dest address, msg length)
st X+, r16 ; destination address
eor r17, r16
ldi r16, 4 ; 4 bytes payload
st X+, r16
eor r17, r16
; write payload
ldi r16, CPRO_CMD_TWIBUSMEMBER ; send command
st X+, r16
eor r17, r16
lds r16, comAddress ; send source address
st X+, r16
eor r17, r16
mov r16, r1 ; send i2c bus member address
st X+, r16
eor r17, r16
mov r16, r2 ; send i2c bus member availability
st X+, r16
eor r17, r16
; store XOR byte
st X+, r17
; mark buffer as enqueued with PRIO "info" (limited amount of retries)
ldi r20, COM_BUFFER_PRIO_INFO
rcall COM_EnqueuePacket ; (R15, R16)
brcc CPRO_EnqueueTwiBusMember_error
sec
ret
CPRO_EnqueueTwiBusMember_error:
clc
ret