martin/aqhomecontrol
Public Access
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

avr: beautifications.

Browse Source
This commit is contained in:
Martin Preuss
2024-09-18 00:12:56 +02:00
parent b490646799
commit 5b3c813981
1 changed files with 13 additions and 13 deletions
Download Patch File Download Diff File Expand all files Collapse all files

26
avr/modules/com2/lowlevel.asm
View File

@@ -27,32 +27,32 @@
; MODIFIED REGS: R16, R21, R22
com2SendByte:
ldi r21, 8 ; +1 bits left
ldi r21, 8 ; +1 bits left
; send startbit
cbi COM_PORT_DATA, COM_PINNUM_DATA ; +2 set DATA low
sbi COM_DDR_DATA, COM_PINNUM_DATA ; +2 set DATA as output
Utils_WaitNanoSecs COM_BIT_LENGTH, 5, r22 ; wait for one bit duration
cbi COM_PORT_DATA, COM_PINNUM_DATA ; +2 set DATA low
sbi COM_DDR_DATA, COM_PINNUM_DATA ; +2 set DATA as output
Utils_WaitNanoSecs COM_BIT_LENGTH, 5, r22 ; wait for one bit duration
; send data bits
com2SendByte_loop: ; 9 for low bit
lsr r16 ; 1+ bit to send -> CARRY
lsr r16 ; 1+ bit to send -> CARRY
brcs com2SendByte_setHigh ; HI: +2, LO: +1
com2SendByte_setLow:
sbi COM_DDR_DATA, COM_PINNUM_DATA ; +2 set DATA as output
sbi COM_DDR_DATA, COM_PINNUM_DATA ; +2 set DATA as output
Utils_WaitNanoSecs COM_BIT_LENGTH, 9, r22
rjmp com2SendByte_loopEnd ; +2
com2SendByte_setHigh:
cbi COM_DDR_DATA, COM_PINNUM_DATA ; +2 set DATA as input, pullup R makes it ONE
nop ; +1 (to make pin change available)
Utils_WaitNanoSecs COM_BIT_LENGTH/2, 11, r22 ; wait for half a bit length for line to safely settle
sbis COM_PIN_DATA, COM_PINNUM_DATA ; +1 if no skip, +2 if skipped
cbi COM_DDR_DATA, COM_PINNUM_DATA ; +2 set DATA as input, pullup R makes it ONE
nop ; +1 (to make pin change available)
Utils_WaitNanoSecs COM_BIT_LENGTH/2, 11, r22 ; wait for half a bit length for line to safely settle
sbis COM_PIN_DATA, COM_PINNUM_DATA ; +1 if no skip, +2 if skipped
rjmp com2SendByte_error ; +2 if error (collision: we wanted line to be high but it is low)
Utils_WaitNanoSecs COM_BIT_LENGTH/2, 0, r22
com2SendByte_loopEnd:
dec r21 ; +1
dec r21 ; +1
brne com2SendByte_loop ; +2, sum per loop: 10 cycles
; send stopbit
cbi COM_DDR_DATA, COM_PINNUM_DATA ; +2 set DATA as input, pullup R makes it ONE
Utils_WaitNanoSecs COM_BIT_LENGTH, 4, r22 ; wait for one bit length
cbi COM_DDR_DATA, COM_PINNUM_DATA ; +2 set DATA as input, pullup R makes it ONE
Utils_WaitNanoSecs COM_BIT_LENGTH, 4, r22 ; wait for one bit length
rjmp com2LowLevelSecRet
com2SendByte_error: