IRQ handler for UP9600

c64/aliases/,aliases_ram_lowmem.s

@@ -114,7 +114,7 @@
 	.label INBIT     = $A7  //          -- NOT IMPLEMENTED --
 #if !CONFIG_LEGACY_SCNKEY
 	.label BITCI     = $A8  //          -- NOT IMPLEMENTED --
-	.label RINONE    = $A9  //          -- NOT IMPLEMENTED --
+	.label RINONE    = $A9  //          -- WIP -- (UP9600 only) RS-232 check for start bit flag
 	.label RIDDATA   = $AA  //          -- NOT IMPLEMENTED --
 	.label RIPRTY    = $AB  //          -- NOT IMPLEMENTED --
 #endif

c64/kernal/interrupts/ea31.default_irq_handler.s

@@ -1,10 +1,22 @@
 
 default_irq_handler:
 
+#if CONFIG_RS232_UP9600
+
+	jsr rs232_count_channels
+	cpx #$00
+	beq !+
+	jsr up9600_irq
+!:
+
+#endif // CONFIG_RS232_UP9600
+
+
 	jsr cursor_blink
 	jsr JSCNKEY
 	jsr JUDTIM // update jiffy clock
 
+
 #if CONFIG_TAPE_NORMAL || CONFIG_TAPE_TURBO
 
 	// Turn tape motor on/off depending on the button state
@@ -25,7 +37,8 @@ default_irq_handler:
 
 default_irq_handler_end_tape:
 
-#endif
+#endif // CONFIG_TAPE_NORMAL || CONFIG_TAPE_TURBO
+
 
 	// Acknowledge CIA interrupt and return
 	jmp clear_cia1_interrupt_flag_and_return_from_interrupt

c64/kernal/interrupts/fe47.default_nmi_handler.s

@@ -17,9 +17,10 @@ default_nmi_handler:
 	bne !+
 	jmp (ICART_WARM_START)
 !:
-
 	// According to C64 Wiki, if STOP key is pressed, the routine assumes warm start request
 
+	// XXX is it right? how to check that IRQ was caused by RESTORE?
+
 	jsr JSTOP
 	bcs !+
 	jmp return_from_interrupt // no STOP pressed

c64/kernal/rs232/close_rs232.s

@@ -18,6 +18,7 @@ close_rs232:
 	// If more than one, skip deallocation (other channels still uses the buffer).
 
 	jsr rs232_count_channels
+	cpx #$02                           // set Carry if more than one is open
 	bcs close_rs232_end
 
 	// Deallocate buffer

c64/kernal/rs232/open_rs232.s

@@ -18,6 +18,7 @@ open_rs232:
 	// If more than one, skip allocation (already allocated).
 
 	jsr rs232_count_channels
+	cpx #$02                           // set Carry if more than one is open
 	bcs open_rs232_end
 
 	// Allocate buffers - first RIBUF, afterwards ROBUF
@@ -43,6 +44,14 @@ open_rs232:
 	sta RODBS
 	sta RODBE
 
+
+#if CONFIG_RS232_UP9600
+
+	jmp up9600_enable
+
+#endif // CONFIG_RS232_UP9600
+
+
 open_rs232_end:
 
 	jmp open_done_success

c64/kernal/rs232/rs232_count_channels.s

@@ -1,7 +1,7 @@
 
 //
 // Sets .X to number of open RS-232 channels
-// Sets Carry if more than one is open
+//
 
 
 #if HAS_RS232
@@ -20,8 +20,6 @@ rs232_count_channels:
 	inx
 	bpl !- // branch always
 	
-	cpx #$02
-	
 	rts
 
 

c64/kernal/rs232/up9600_enable.s

@@ -1,6 +1,6 @@
 
 //
-// Enable UP9600 interface
+// Enable UP9600 interface support
 //
 
 // Based on UP9600 code by Daniel Dallman with Bo Zimmerman adaptations
@@ -11,6 +11,63 @@
 
 up9600_enable: // XXX adapt
 
+	sei
+
+
+
+	lda IRQVECT
+	cmp #<ORIGIRQ
+	bne INSTERR; IRQ-VECTOR ALREADY CHANGED
+	lda IRQVECT+1
+	cmp #>ORIGIRQ
+	bne INSTERR; IRQ-VECTOR ALREADY CHANGED
+	lda NMIVECT
+	cmp #<ORIGNMI
+	bne INSTERR; NMI-VECTOR ALREADY CHANGED
+	lda NMIVECT+1
+	cmp #>ORIGNMI
+	bne INSTERR; NMI-VECTOR ALREADY CHANGED
+	ldy #0
+	sty RODBE
+	sty RODBS
+	sty RIDBE
+	sty RIDBS
+	;  PROBE FOR RS232 INTERFACE
+	cli
+	lda #$7F
+	sta CIA2_ICR // $DD0D ; DISABLE ALL NMIS
+	lda #$80
+	sta CIA2_DDRB // $DD03 ; PB7 USED AS OUTPUT
+	sta $DD0E; STOP TIMERA
+	sta CIA2_CRB // $DD0F ; STOP TIMERB
+	bit CIA2_ICR // $DD0D ; CLEAR PENDING INTERRUPTS
+	ldx #8
+INSTALL2
+	stx CIA2_PRB // $DD01; TOGGLE TXD
+	sta CIA2_PRB // $DD01; AND LOOK IF IT TRIGGERS AN
+	dex; SHIFT-REGISTER INTERRUPT
+	bne INSTALL2
+	lda CIA2_ICR // $DD0D ; CHECK FOR BIT3 (SDR-FLAG)
+	and #8
+	beq INSTERR; NO INTERFACE DETECTED
+	;  GENERATE LOOKUP TABLE
+	ldx #0
+INSTALL3
+	stx OUTSTAT; OUTSTAT USED AS TEMPORARY VARIABLE
+	ldy #8
+INSTALL4
+	asl OUTSTAT
+	ror
+	dey
+	bne INSTALL4
+	sta REVTAB,X
+	inx
+	bpl INSTALL3
+
+
+
+
+
 	sei
 	// XXX set NEWIRQ as IRQ vector
 	// XXX set NMIDOBIT as NMI vector
@@ -63,4 +120,14 @@ ENABLE2
 	rts
 
 
+
+
+INSTERR
+	cli
+	sec
+	rts
+
+
+
+
 #endif // CONFIG_RS232_UP9600

c64/kernal/rs232/up9600_irq.s

@@ -0,0 +1,40 @@
+
+//
+// RS-232 IRQ handler part
+//
+
+// Based on UP9600 code by Daniel Dallman with Bo Zimmerman adaptations
+
+
+#if CONFIG_RS232_UP9600
+
+
+up9600_irq:
+
+	lda CIA1_ICR // $DC0D
+
+	lsr
+	lsr                                // move bit 1 (timer B flag) into Carry
+	and #$02                           // test SDR (shift register) status
+
+	beq up9600_irq_continue
+
+	ldx RINONE
+	beq !+                             // skip if not waiting for empty SDR
+	dex
+	stx RINONE
+!:
+	bcc up9600_irq_end
+
+up9600_irq_continue:
+
+	rts
+
+up9600_irq_end:
+
+	pla
+	pla
+	jmp return_from_interrupt
+
+
+#endif // CONFIG_RS232_UP9600

c64/kernal/rs232/up9600_nmi.s

@@ -6,19 +6,14 @@
 // Based on UP9600 code by Daniel Dallman with Bo Zimmerman adaptations
 
 
-// XXX integrate with NMI handler
-
-
 #if CONFIG_RS232_UP9600
 
 
 up9600_nmi:
-	// XXX integrate this
+	// XXX integrate with NMI handler
 
-
-NMIDOBIT
 	pha
-	bit CIA2_ICR // $DD0D; CHECK BIT 7 (STARTBIT PRINT)
+	bit CIA2_ICR // $DD0D; check if CIA caused the interrupt
 	bpl NMIDOBI2; NO STARTBIT RECEIVED, THEN SKIP
 	lda #$13
 	sta CIA2_CRB // $DD0F; START TIMER B (FORCED RELOAD, SIGNAL AT PB7)