Files
aqhomecontrol/avr/modules/rtc/ds3231/main.asm
2026-03-15 20:20:06 +01:00

227 lines
5.2 KiB
NASM

; ***************************************************************************
; copyright : (C) 2026 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. *
; ***************************************************************************
; ***************************************************************************
; defs
.equ DS3231_FLAGS_PRESENT_BIT = 7
.equ DS3231_FLAGS_VALID_BIT = 6
; ***************************************************************************
; data
.dseg
ds3231DataBegin:
ds3231Flags: .byte 1
ds3231RecvBuffer: .byte 7
ds3231DataEnd:
; ***************************************************************************
; code
.cseg
; ---------------------------------------------------------------------------
; @routine Ds3231_Init @global
;
; @return CFLAG set if okay, cleared on error
; @clobbers
Ds3231_Init:
ldi xh, HIGH(ds3231DataBegin)
ldi xl, LOW(ds3231DataBegin)
clr r16
ldi r17, (ds3231DataEnd-ds3231DataBegin)
rcall Utils_FillSram
rcall ds3231CheckPresence
brcc Ds3231_Init_ret
ldi r16, (1<<DS3231_FLAGS_PRESENT_BIT)
sts ds3231Flags, r16
sec
Ds3231_Init_ret:
ret
; @end
; ---------------------------------------------------------------------------
; @routine Ds3231_Fini @global
;
; @return CFLAG set if okay, cleared on error
; @clobbers none
Ds3231_Fini:
ret
; @end
; ---------------------------------------------------------------------------
; @routine Ds3231_Fini @global
;
; @return CFLAG set if okay, cleared on error
; @clobbers
Ds3231_OnEveryMinute:
push r15
in r15, SREG
cli
lds r16, ds3231Flags
sbrs r16, DS3231_FLAGS_PRESENT_BIT
rjmp Ds3231_OnEveryMinute_ret
; clear valid bit
cbr r16, (1<<DS3231_FLAGS_VALID_BIT)
sts ds3231Flags, r16
; read time from clock
ldi xl, LOW(ds3231RecvBuffer)
ldi xh, HIGH(ds3231RecvBuffer)
clr r16
ldi r17, 7
rcall ds3231ReadData
brcc Ds3231_OnEveryMinute_ret
; set valid bit
lds r16, ds3231Flags
sbr r16, (1<<DS3231_FLAGS_VALID_BIT)
sts ds3231Flags, r16
#ifdef MODULES_NETWORK
; rcall ds3231SendDebug
rcall Ds3231_AnnounceTime
#endif
Ds3231_OnEveryMinute_ret:
out SREG, r15
pop r15
ret
; @end
; ---------------------------------------------------------------------------
; @routine ds3231CheckPresence
;
; Expects interrupts being disabled!
;
; @return CFLAG set if okay, clear on error
; @clobbers R16 (R17, R18, R22)
ds3231CheckPresence:
ldi r16, (DS3231_ADDR*2) ; write access
rjmp twiCheckPresence ; (R16, R17, R18, R22)
; @end
; ---------------------------------------------------------------------------
; @routine ds3231ReadData
;
; @param r16 start address
; @param r17 number of bytes to read
; @param X pointer to buffer to receive data
; @return CFLAG set if okay, cleared on error
; @return r16 number of bytes received if CFLAG set
; @clobbers r16, r17, r18, r19, r20, r22, X
ds3231ReadData:
mov r20, r16
mov r19, r17
rcall twiStart ; (R22)
ldi r16, (DS3231_ADDR*2) ; write access
rcall twiSendByteExpectAck ; (R16, R17, R18, R22)
brcc ds3231ReadData_error
mov r16, r20
rcall twiSendByteExpectAck
brcc ds3231ReadData_error
rcall twiRestart ; (R22)
ldi r16, (DS3231_ADDR*2)+1 ; read access
rcall twiSendByteExpectAck
brcc ds3231ReadData_error
clr r20
ds3231ReadData_loop1:
cpi r19, 1
breq ds3231ReadData_recvLast
rcall twiReceiveByteSendAck ; (R16, R17, R18, R22)
rjmp ds3231ReadData_recvd
ds3231ReadData_recvLast:
rcall twiReceiveByte ; don't send ACK (R16, R17, R18, R22)
ds3231ReadData_recvd:
brcc ds3231ReadData_error
st X+, r16
inc r20
dec r19
brne ds3231ReadData_loop1
rcall twiStop ; (R22)
mov r16, r20
sec
ret
ds3231ReadData_error:
rcall twiStop ; (R22)
clc
ret
; @end
; ---------------------------------------------------------------------------
; @routine ds3231SendData
;
; @param r16 start address
; @param r17 number of bytes to read
; @param Z pointer to buffer to send
; @return CFLAG set if okay, cleared on error
; @return r16 number of bytes received if CFLAG set
; @clobbers r16, r17, r18, r19, r20, r22, Z
ds3231SendData:
mov r20, r16
mov r19, r17
rcall twiStart ; (R22)
ldi r16, (DS3231_ADDR*2) ; write access
rcall twiSendByteExpectAck ; (R16, R17, R18, R22)
brcc ds3231SendData_error
mov r16, r20 ; address
rcall twiSendByteExpectAck ; (R16, R17, R18, R22)
brcc ds3231SendData_error
clr r20
ds3231SendData_loop1:
ld r16, Z+
rcall twiSendByteExpectAck ; (R16, R17, R18, R22)
brcc ds3231SendData_error
inc r20
dec r19
brne ds3231SendData_loop1
rcall twiStop ; (R22)
mov r16, r20
sec
ret
ds3231SendData_error:
rcall twiStop ; (R22)
clc
ret
; @end