avr: some ideas for autosync.

2025-05-29 12:47:41 +02:00
parent af75532ba7
commit 46720d791c
1 changed files with 170 additions and 0 deletions
--- a/avr/modules/flash/io_softuart.asm
+++ b/avr/modules/flash/io_softuart.asm
@@ -0,0 +1,170 @@
+; ***************************************************************************
+; copyright   : (C) 2025 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.   *
+; ***************************************************************************
+
+
+.equ UARTSOFT_WAITFORSYNCSTART = 200
+
+
+; ***************************************************************************
+; code
+
+
+.cseg
+
+
+
+
+
+uartSoftWaitAndReadSyncByte:
+; wait for begin of startbit
+  ldi r24, LOW(UARTSOFT_WAITFORSYNCSTART)
+  ldi r25, HIGH(UARTSOFT_WAITFORSYNCSTART)
+uartSoftWaitAndReadSyncByte_loop0:
+    sbis COM_DATA_INPUT, COM_DATA_PIN
+      rjmp uartSoftWaitAndReadSyncByte_gotStartBit
+    sbiw r25:r24, 1
+  brne uartSoftWaitAndReadSyncByte_loop0
+uartSoftWaitAndReadSyncByte_error:                     ; timeout
+  clc
+  ret
+
+uartSoftWaitAndReadSyncByte_gotStartBit:
+  clr r25
+  clr r24
+; count cycles while DATA low (count length of startBit)
+uartSoftWaitAndReadSyncByte_loopLow:                   ; 5 cycles per loop +3 cycles to leave loop
+    sbic COM_DATA_INPUT, COM_DATA_PIN                  ; +2 (skip)/+1 (no skip)
+      rjmp uartSoftWaitAndReadSyncByte_startDataBit1   ; +0 (skip) / +2 (no skip)
+    adiw r25:r24, 1                                    ; +1
+  brne uartSoftWaitAndReadSyncByte_loopLow             ; +2
+  rjmp uartSoftWaitAndReadSyncByte_error
+
+uartSoftWaitAndReadSyncByte_startDataBit1:
+  clr r25
+  clr r24
+  ldi r17, 4
+uartSoftWaitAndReadSyncByte_loopData:
+  ; count cycles while DATA high (count length of dataBit)
+  uartSoftWaitAndReadSyncByte_loopDataHigh:              ; 5 cycles per loop +3 cycles to leave loop
+      sbis COM_DATA_INPUT, COM_DATA_PIN                  ; +2 (skip)/+1 (no skip)
+        rjmp uartSoftWaitAndReadSyncByte_startLowDataBit ; +0 (skip) / +2 (no skip)
+      adiw r25:r24, 1                                    ; +1
+    brne uartSoftWaitAndReadSyncByte_loopDataHigh               ; +2
+  ; too long LOW
+    rjmp uartSoftWaitAndReadSyncByte_error
+  uartSoftWaitAndReadSyncByte_startLowDataBit:
+  ; count cycles while DATA low (count length of dataBit)
+uartSoftWaitAndReadSyncByte_loopDataLow:                 ; 5 cycles per loop +3 cycles to leave loop
+      sbic COM_DATA_INPUT, COM_DATA_PIN                   ; +2 (skip)/+1 (no skip)
+        rjmp uartSoftWaitAndReadSyncByte_startHighDataBit ; +0 (skip) / +2 (no skip)
+      adiw r25:r24, 1                                     ; +1
+    brne uartSoftWaitAndReadSyncByte_loop4                ; +2
+  ; too long LOW
+    rjmp uartSoftWaitAndReadSyncByte_error
+uartSoftWaitAndReadSyncByte_startHighDataBit:
+    dec r17
+  brne uartSoftWaitAndReadSyncByte_loopData 
+; calc average (8 values)
+  lsr r25  ; /2
+  ror r24
+  lsr r25  ; /4
+  ror r24
+  lsr r25  ; /8
+  ror r24
+  sec
+  ret
+; @end
+
+
+
+
+
+
+
+
+uartSoftReceiveByte:
+; wait for begin of startbit
+  ldi r24, LOW(UARTSOFT_WAITFORSYNCSTART)
+  ldi r25, HIGH(UARTSOFT_WAITFORSYNCSTART)
+uartSoftReceiveByte_waitForBeginOfStartBit:
+    sbis COM_DATA_INPUT, COM_DATA_PIN
+      rjmp uartSoftReceiveByte_gotBeginOfStartBit
+    sbiw r25:r24, 1
+  brne uartSoftReceiveByte_waitForBeginOfStartBit
+uartSoftReceiveByte_error:                             ; timeout
+  clc
+  ret
+
+uartSoftReceiveByte_gotBeginOfStartBit:
+  clr r25
+  clr r24
+; count cycles while DATA low (count length of startBit)
+uartSoftReceiveByte_waitForEndOfStartBit:              ; 5 cycles per loop
+    sbic COM_DATA_INPUT, COM_DATA_PIN                  ; +2 (skip)/+1 (no skip)
+      rjmp uartSoftReceiveByte_gotEndOfStartBit        ; +0 (skip) / +2 (no skip)
+    adiw r25:r24, 1                                    ; +1
+  brne uartSoftWaitAndReadSyncByte_loopLow             ; +2
+  rjmp uartSoftReceiveByte_error
+uartSoftReceiveByte_gotEndOfStartBit:
+; r25:r24=counter equivalent for length of startbit
+  clr r16
+  ldi r17, 8
+uartSoftReceiveByte_bitLoop:
+  ; TODO: receive 8bits, wait for start of endbit
+  
+  ret
+
+
+
+
+
+
+
+
+
+uartSoftCountDataLow:                                  ; 5 cycles per loop +5 cycles outside (+3 cycles RCALL)
+    sbic COM_DATA_INPUT, COM_DATA_PIN                  ; +2 (skip)/+1 (no skip)
+      rjmp uartSoftCountDataLow_ok                     ; +0 (skip) / +2 (no skip)
+    adiw r25:r24, 1                                    ; +1
+  brne uartSoftCountDataLow                            ; +2
+  clc
+  ret
+uartSoftCountDataLow_ok:
+  sec
+  ret
+; @end
+
+
+
+uartSoftCountDataHigh:                                 ; 5 cycles per loop +5 cycles outside (+3 cycles RCALL)
+    sbis COM_DATA_INPUT, COM_DATA_PIN                  ; +2 (skip)/+1 (no skip)
+      rjmp uartSoftCountDataHigh_ok                    ; +0 (skip) / +2 (no skip)
+    adiw r25:r24, 1                                    ; +1
+  brne uartSoftCountDataHigh                           ; +2
+  clc
+  ret
+uartSoftCountDataHigh_ok:
+  sec                                                  ; +1
+  ret                                                  ; +4
+; @end
+
+
+
+uartSoftWaitBitTime:                                   ; 5 cycles per loop +5 cycles outside (+3 cycles RCALL)
+uartSoftWaitBitTime_loop:
+    nop                                                ; +1
+    nop                                                ; +1
+    sbiw r25:r24, 1                                    ; +1
+  brne uartSoftWaitBitTime_loop                        ; +2
+  nop                                                  ; +1
+  ret                                                  ; +4
+; @end
+
+
+