simplified message handling, switch from XOR checksum to CRC8 with polynomial 0x97.

0x97 allows for detection of all 1-3 bit errors in a message of up to 119 bytes (see https://www.faa.gov/aircraft/air_cert/design_approvals/air_software/media/TC-14-49.pdf)
2023-04-07 23:22:40 +02:00
parent 4e1f08b567
commit 7eb462173c
33 changed files with 281 additions and 367 deletions
--- a/avr/comproto_values.asm
+++ b/avr/comproto_values.asm
@@ -44,7 +44,7 @@ CPRO_EnqueueValue:
      st X+, r11                             ; 11: high denom
    pop xl
  pop xh
-  rcall comCalcAndAddChecksumByte
+  rcall comCalcAndAddChecksumByte            ; (R16, R17, R18, R19, X)

  ; mark buffer as enqueued with PRIO "normal" (slightly limited number of retries)
  ldi r20, COM_BUFFER_PRIO_NORMAL