try new implementation of UART code for m8515.

avr/modules/uart_hw/attn.asm

@@ -0,0 +1,102 @@
+; ***************************************************************************
+; 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.   *
+; ***************************************************************************
+
+
+
+; ***************************************************************************
+; code
+
+.cseg
+
+
+; ---------------------------------------------------------------------------
+; @routine ATTN_Init @global
+;
+; @clobbers R16
+
+ATTN_Init:
+.ifdef INT0
+  .if COM_IRQ_BIT_ATTN == INT0
+    M_IO_READ r16, MCUCR
+    cbr r16, (1<<ISC01) | (1<<ISC00)
+    sbr r16, (1<<ISC01) | (0<<ISC00)        ; falling edge of ATTN
+  ;  sbr r16, (0<<ISC01) | (0<<ISC00)         ; low level triggers
+  
+  rcall ATTN_SetHighEnableIrq
+  
+  ret
+; @end
+
+
+
+
+; ---------------------------------------------------------------------------
+; @routine ATTN_SetLowDisableIrq @global
+;
+; @clobbers R16
+
+ATTN_SetLowDisableIrq:
+.ifdef INT0
+  .if COM_IRQ_BIT_ATTN == INT0
+    M_IO_READ r16, COM_IRQ_ADDR_ATTN        ; disable irq for ATTN line
+    cbr r16, (1<<COM_IRQ_BIT_ATTN)
+    M_IO_WRITE COM_IRQ_ADDR_ATTN, r16
+  .endif
+.endif
+
+  sbi COM_ATTN_DDR, COM_ATTN_PIN            ; set ATTN as output
+  cbi COM_ATTN_OUTPUT, COM_ATTN_PIN         ; set ATTN low
+  
+  ret
+; @end
+
+
+
+; ---------------------------------------------------------------------------
+; @routine ATTN_SetHighEnableIrq @global
+;
+; @clobbers R16
+
+ATTN_SetHighEnableIrq:
+  cbi COM_ATTN_DDR, COM_ATTN_PIN           ; set ATTN as input
+.ifdef COM_ATTN_PUE
+  cbi COM_ATTN_PUE, COM_ATTN_PIN           ; disable pullup on ATTN
+.else
+  cbi COM_ATTN_OUTPUT, COM_ATTN_PIN        ; disable pullup on ATTN
+.endif
+
+.ifdef INT0
+  .if COM_IRQ_BIT_ATTN == INT0
+    M_IO_READ r16, COM_IRQ_ADDR_ATTN        ; enable irq for ATTN line
+    sbr r16, (1<<COM_IRQ_BIT_ATTN)
+    M_IO_WRITE COM_IRQ_ADDR_ATTN, r16
+  .endif
+.endif
+
+  ret
+; @end
+
+
+
+; ---------------------------------------------------------------------------
+; @routine ATTN_IsHigh @global
+;
+; @return CFLAG set if ATTN is high
+; @clobbers none
+
+ATTN_IsHigh:
+  clc
+  sbic COM_ATTN_INPUT, COM_ATTN_PIN     ; ATTN low?
+    sec                                 ; yes, set CF
+  ret
+; @end
+
+
+
+