From 20b7c3f50da87044c1b08e601a12da51656be3a9 Mon Sep 17 00:00:00 2001
From: Martin Preuss <martin@aquamaniac.de>
Date: Tue, 1 Jul 2025 00:52:44 +0200
Subject: [PATCH] avr: new uart_hw2 module comonuart1 works now.

---
 avr/modules/uart_hw2/comonuart1.asm | 139 ++++++++++++++++------------
 1 file changed, 80 insertions(+), 59 deletions(-)

diff --git a/avr/modules/uart_hw2/comonuart1.asm b/avr/modules/uart_hw2/comonuart1.asm
index 3df179b..a9e3f27 100644
--- a/avr/modules/uart_hw2/comonuart1.asm
+++ b/avr/modules/uart_hw2/comonuart1.asm
@@ -31,13 +31,20 @@ ComOnUart1_Init:
   ldi yh, HIGH(comOnUart1_iface)
   rcall NET_Interface_Init                  ; (R16, R17, X)
   ldi r16, 0xff
-  std Y+UART_HW_IFACE_OFFS_WRITEBUFNUM, r16
+  std Y+UART_HW2_IFACE_OFFS_WRITEBUFNUM, r16
   ldi r16, UART_HW2_MODE_IDLE
   std Y+UART_HW2_IFACE_OFFS_MODE, r16
   clr r16
   std Y+NET_IFACE_OFFS_IFACENUM, r16
   rcall comOnUart1SetAttnInput
 
+  sbi COM_IRQ_ADDR_ATTN1, COM_IRQ_BIT_ATTN1 ; enable pin change irq for ATTN line
+  inr r16, GIMSK                           ; enable pin change irq PCIE0 or PCIE1
+  sbr r16, (1<<COM_IRQ_GIMSK_ATTN1)
+  outr GIMSK, r16
+  ldi r16, (1<<COM_IRQ_GIFR_ATTN1)         ; clear pending irq by writing 1 to ATTN bit
+  outr GIFR, r16
+
   ; set baudrate
 .if clock == 8000000
   ldi r16, 25 ; (19.2Kb/s at 8MHz)
@@ -49,12 +56,12 @@ ComOnUart1_Init:
   ldi r17, 0  
 .endif
 
-  sts UBRR1H, r17
-  sts UBRR1L, r16
+  outr UBRR1H, r17
+  outr UBRR1L, r16
 
   ; set character format 
   ldi r16, (1<<USBS1)|(3<<UCSZ10)
-  sts UCSR1C, r16
+  outr UCSR1C, r16
   sec
   ret
 ; @end
@@ -138,15 +145,11 @@ comOnUart1StartReading:
 ; @param Y pointer to interface data in SRAM
 ; @param R16 buffer number
 ; @return CFLAG set if writing started, cleared otherwise
-; @clobbers R16, R17, X, Z (R24, R25)
+; @clobbers R16, R17, X, Z (R22, R24, R25)
 
 comOnUart1StartWriting:
-  rcall comOnUart1IsAttnLow                  ; (none)
-  brcs comOnUart1StartWriting_ebusy
-  ; set ATTN low
-  rcall comOnUart1SetAttnLow                 ; (none)
-  Utils_WaitNanoSecs COM_BIT_LENGTH, 0, r22  ; wait for one bit duration
-  Utils_WaitNanoSecs COM_BIT_LENGTH, 0, r22  ; wait for one bit duration
+  rcall comOnUart1AcquireAttn                ; (R22)
+  brcc comOnUart1StartWriting_ebusy
   ; copy buffer
   rcall NET_Buffer_Locate                    ; (R17)
   std Y+UART_HW2_IFACE_OFFS_WRITEBUFNUM, r16
@@ -256,7 +259,7 @@ comOnUart1RunIdle:
   ; look for outbound message
   rcall NET_Interface_PeekNextOutgoingMsgNum ; r16=msgNum
   brcc comOnUart1RunIdle_end                 ; no outmsg in queue
-  rcall comOnUart1StartWriting               ; (R16, R17, R24, R25, X, Z)
+  rcall comOnUart1StartWriting               ; (R16, R17, R22, R24, R25, X, Z)
   brcc comOnUart1RunIdle_end
   rcall NET_Interface_GetNextOutgoingMsgNum  ; take current msg off the queue
 comOnUart1RunIdle_end:
@@ -298,52 +301,48 @@ comOnUart1RunSkipping_end:
 ; @routine comOnUart1RunMsgReceived
 ;
 ; @param Y pointer to interface data in SRAM
-; @clobbers R16, R17, R18, X (R19, R20, R24, R25)
+; @clobbers R16, R17, R18, X, Z (R19, R20, R24, R25)
 
 comOnUart1RunMsgReceived:
-  push zl
-    push zh
-      mov xl, yl
-      mov xh, yh
-      adiw xh:xl, UART_HW2_IFACE_OFFS_BUFFER
-      mov zl, xl                                    ; Z=buffer in IFACE
-      mov zh, xh
-      rcall NETMSG_CheckMessageInBuffer             ; (R16, R17, R18, R19, R20, X)
-      brne comOnUart1RunMsgReceived_econtent
-      ; msg valid, alloc buffer
-      rcall NET_Buffer_Alloc                        ; X=buffer, R16=bufnum (R16, R17, X)
-      brcc comOnUart1RunMsgReceived_enobuf
-      mov r18, r16                                  ; buffer num
-      rcall NET_Interface_SetIfaceNumInBuffer       ; (R16, R17)
-      adiw xh:xl, 1
-      ldd r17, Y+UART_HW2_IFACE_OFFS_BUFUSED        ; always is at least 2 here
+  mov xl, yl
+  mov xh, yh
+  adiw xh:xl, UART_HW2_IFACE_OFFS_BUFFER
+  mov zl, xl                                    ; Z=buffer in IFACE
+  mov zh, xh
+  rcall NETMSG_CheckMessageInBuffer             ; (R16, R17, R18, R19, R20, X)
+  brcc comOnUart1RunMsgReceived_econtent
+  ; msg valid, alloc buffer
+  rcall NET_Buffer_Alloc                        ; X=buffer, R16=bufnum (R16, R17, X)
+  brcc comOnUart1RunMsgReceived_enobuf
+  mov r18, r16                                  ; buffer num
+  rcall NET_Interface_SetIfaceNumInBuffer       ; (R16, R17)
+  adiw xh:xl, 1
+  ldd r17, Y+UART_HW2_IFACE_OFFS_BUFUSED        ; always is at least 2 here
 comOnUart1RunMsgReceived_copyLoop:
-        ld r16, Z+
-        st X+, r16
-        dec r17
-      brne comOnUart1RunMsgReceived_copyLoop
-      mov r16, r18                                  ; buffer num
-      rcall NET_AddIncomingMsgNum                   ; (R17, R18, X)
-      brcc comOnUart1RunMsgReceived_enoadd
-      ldi r16, NET_IFACE_OFFS_PACKETSIN_LOW
-      rcall NET_Interface_IncCounter16              ; (R24, R25)
-      rjmp comOnUart1RunMsgReceived_setIdleAndEnd
+    ld r16, Z+
+    st X+, r16
+    dec r17
+  brne comOnUart1RunMsgReceived_copyLoop
+  mov r16, r18                                  ; buffer num
+  rcall NET_AddIncomingMsgNum                   ; (R17, R18, X)
+  brcc comOnUart1RunMsgReceived_enoadd
+  ldi r16, NET_IFACE_OFFS_PACKETSIN_LOW
+  rcall NET_Interface_IncCounter16              ; (R24, R25)
+  rjmp comOnUart1RunMsgReceived_setIdleAndEnd
 comOnUart1RunMsgReceived_enoadd:
-      rcall NET_Buffer_ReleaseByNum
-      rjmp comOnUart1RunMsgReceived_enobuf
+  rcall NET_Buffer_ReleaseByNum
+  rjmp comOnUart1RunMsgReceived_enobuf
 comOnUart1RunMsgReceived_enobuf:
-      ldi r16, NET_IFACE_OFFS_ERR_NOBUF_LOW
-      rjmp comOnUart1RunMsgReceived_err
+  ldi r16, NET_IFACE_OFFS_ERR_NOBUF_LOW
+  rjmp comOnUart1RunMsgReceived_err
 comOnUart1RunMsgReceived_econtent:
-      ldi r16, NET_IFACE_OFFS_ERR_CONTENT_LOW
+  ldi r16, NET_IFACE_OFFS_ERR_CONTENT_LOW
 comOnUart1RunMsgReceived_err:
-      rcall NET_Interface_IncCounter16              ; (R24, R25)
+  rcall NET_Interface_IncCounter16              ; (R24, R25)
 comOnUart1RunMsgReceived_setIdleAndEnd:
-      ldi r16, UART_HW2_MODE_IDLE
-      rcall comOnUart1SetMode                       ; (R17)
+  ldi r16, UART_HW2_MODE_IDLE
+  rcall comOnUart1SetMode                       ; (R17)
 comOnUart1RunMsgReceived_end:
-    pop zl
-  pop zh
   ret
 ; @end
 
@@ -398,6 +397,30 @@ comOnUart1RunMsgSent:
 
 
 
+; ---------------------------------------------------------------------------
+; @routine comOnUart1AcquireAttn
+;
+; Set ATTN low only if it is high.
+; @return CFLAG set if ATTN acquired (including waiting time), cleared otherwise
+;
+; @clobbers R22
+
+comOnUart1AcquireAttn:
+  rcall comOnUart1IsAttnLow                  ; (none)
+  brcc comOnUart1AcquireAttn_isHigh
+  clc
+  rjmp comOnUart1AcquireAttn_end
+comOnUart1AcquireAttn_isHigh:
+  ; set ATTN low
+  rcall comOnUart1SetAttnLow                 ; (none)
+  Utils_WaitNanoSecs COM_BIT_LENGTH, 0, r22  ; wait for one bit duration
+  Utils_WaitNanoSecs COM_BIT_LENGTH, 0, r22  ; wait for one bit duration
+  sec
+comOnUart1AcquireAttn_end:
+  ret
+; @end
+
+
 
 ; ---------------------------------------------------------------------------
 ; @routine comOnUart1StartRx
@@ -435,10 +458,10 @@ comOnUart1StopRx:
 comOnUart1StartTx:
   lds r16, UCSR1A
   cbr r16, (1<<TXC1)                             ; clear TXCn interrupt
-  sts UCSR1A, r16
-  lds r16, UCSR1B
+  outr UCSR1A, r16
+  inr r16, UCSR1B
   sbr r16, (1<<UDRIE1) | (1<<TXC1) | (1<<TXEN1)  ; enable TX UDRE and TXC1 interrupt, enable transceive
-  sts UCSR1B, r16
+  outr UCSR1B, r16
   ret
 ; @end
 
@@ -708,13 +731,11 @@ comOnUart1RxCharIsr:
   cpi r18, 2
   brne comOnUart1RxCharIsr_end
   ; determine msg size
-  sbiw xh:xl, 1                                 ; determine message length (msgLen at previous pos)
-  ld r16, X+                                    ; read payload length byte
-  subi r16, -4                                  ; add 4 (buffer header, dest addr, length, crc byte)
-  cpi r16, UART_HW2_BUFFER_SIZE                 ; total msg length ok?
+  inc r16                                       ; last byte was payload length, add byte for crc
+  cp r16, r17                                   ; compare remaining length against remaining space
   brcc comOnUart1RxCharIsr_emsgsize             ; msg too long
-  subi r16, 2                                   ; subtract bytes already received
   std Y+UART_HW2_IFACE_OFFS_BUFLEFT, r16        ; set new number of bytes left
+  tst r16
   brne comOnUart1RxCharIsr_end                  ; jmp if still bytes left to receive
 comOnUart1RxCharIsr_complete:
   rcall comOnUart1StopRx
@@ -750,7 +771,7 @@ comOnUart1RxCharIsr_end:
 
 comOnUart1TxUdreIsr:
   inr r16, UCSR1A
-  sbrs r16,UDRE1
+  sbrs r16, UDRE1
     rjmp comOnUart1TxUdreIsr_disable_irq      ; not ready
   ; check bytes left
   ldd r17, Y+UART_HW2_IFACE_OFFS_BUFLEFT
@@ -763,7 +784,7 @@ comOnUart1TxUdreIsr:
   std Y+UART_HW2_IFACE_OFFS_BUFPOS_LOW, xl
   std Y+UART_HW2_IFACE_OFFS_BUFPOS_HIGH, xh
   ; send byte
-  sts UDR1, r16                               ; send byte
+  outr UDR1, r16                               ; send byte
   ; decreased counter
   dec r17
   std Y+UART_HW2_IFACE_OFFS_BUFLEFT, r17