X-Git-Url: http://cloudbase.mooo.com/gitweb/avrcpm.git/blobdiff_plain/fa9059afcba0c5b044ab9bbc337f2f17df7e72c3..fc67ef420913bf8404ad90582d39538d79875425:/avr/sw-uart.asm?ds=inline

diff --git a/avr/sw-uart.asm b/avr/sw-uart.asm
index 8c2b33f..3216293 100644
--- a/avr/sw-uart.asm
+++ b/avr/sw-uart.asm
@@ -21,7 +21,12 @@
 ;    $Id$
 ;
 
+#ifdef  __ATmega8__
+  #error "ATmega8 is not supported (yet)! Please update this driver, or buy an ATmega88."
+#endif
+
 #define SSER_BIT_TC	(F_CPU+BAUD/2) / BAUD 
+#define SSER_CHAR_TC	(10 * 1000 / BAUD) + 2
 
 #define RXBUFMASK  	RXBUFSIZE-1
 #define TXBUFMASK  	TXBUFSIZE-1
@@ -32,10 +37,12 @@ srx_state:
 	.byte	1
 srx_char_to:
 	.byte	1
+srx_char_time:
+	.byte	1
 srx_dr:
 	.byte	1
-;srx_lastedge:
-;	.byte	2
+srx_lastedge:
+	.byte	2
 stx_bitcount:
 	.byte	1
 stx_dr:
@@ -70,14 +77,23 @@ uart_init:
 ; - Soft UART RX (ICP1/ICR1).
 ; - 1ms System timer is already configured at this point.
 
+
+	cbi	P_TXD-1,TXD			;TXD pin as input
 	ldi	temp,(1<<COM1A1)|(1<<COM1A0)	;OC1A high on compare match (UART TX)
+	ldi	temp2,(1<<FOC1A)		;force compare match
 	outm8	TCCR1A,temp
+	outm8	TCCR1C,temp2
+	sbi	P_TXD-1,TXD			;TXD pin now output (OC1A)
 
-	ldi	temp,(1<<ICF1)			;clear pending int
-	out	TIFR1,temp
-	inm8	temp,TIMSK1
+	ldi	temp,(1<<ICF1)			;clear pending input capture int
+	out	TIFR1,temp			;
+	inm8	temp,TIMSK1			;
 	ori	temp,(1<<ICIE1)			;Enable input capture int.  (UART RX)
-	outm8	TIMSK1,temp
+	outm8	TIMSK1,temp			;
+
+	ldi	temp,SSER_CHAR_TC		;Character TO
+	sts	srx_char_time,temp
+
 	ret
 	
 ;------------------------------------------------------------------
@@ -116,23 +132,23 @@ uart_init:
 
 ; State 0: Wait for start bit
 
-;	sts	srx_lastedge,zl			;save beginning of start bit
-;	sts	srx_lastedge+1,zh
-	movw	srx_lastedgel,zl
+	sts	srx_lastedge,zl			;save beginning of start bit
+	sts	srx_lastedge+1,zh
+;	movw	srx_lastedgel,zl
 	sts	srx_dr,_0
 	ldi	temp,1
 	sts	srx_state,temp
-	ldi	temp,2
+	lds	temp,srx_char_time
 	sts	srx_char_to,temp
 	sbis	P_RXD-2,RXD			;RXD still low?
-	rjmp	srxi_end2
+	rjmp	srxi_end
 	ldi	zl,(1<<ICNC1)|(1<<CS10)		;next edge is falling edge
 	outm8	TCCR1B,zl
 	ldi	zh,(1<<ICF1)			;clear pending int
 	out	TIFR1,zh
 	sts	srx_state,_0
 	sts	srx_char_to,_0
-	rjmp	srxi_end2
+	rjmp	srxi_end
 
 srxi_S1:
 	cpi	temp,1
@@ -140,13 +156,13 @@ srxi_S1:
 
 ; State 1: Check start bit (and collect 0-bits)
 
-;	lds	temp,srx_lastedge
-;	lds	temp2,srx_lastedge+1
-;	sts	srx_lastedge,zl
-;	sts	srx_lastedge+1,zh
+	lds	temp,srx_lastedge
+	lds	temp2,srx_lastedge+1
+	sts	srx_lastedge,zl
+	sts	srx_lastedge+1,zh
 
-	movw	temp,srx_lastedgel
-	movw	srx_lastedgel,zl
+;	movw	temp,srx_lastedgel
+;	movw	srx_lastedgel,zl
 
 	sub	zl,temp
 	sbc	zh,temp2
@@ -174,14 +190,18 @@ srxi_1l:
 srxi_1fe:
 	sts	srx_char_to,_0			; no stop bit --> framing error --> break
 	sts	srx_state,_0
-	sbr	intstat,(1<<i_break)
-	rjmp	srxi_end2
+	sbr	intstat,(1<<i_break)		;
+	sts	rxcount,_0			;clear rx buffer
+	sts	rxidx_w,_0
+	sts	rxidx_r,_0
+
+	rjmp	srxi_end
 
 srxi_1be:
 	sts	srx_dr,temp
 	ldi	temp,2
 	sts	srx_state,temp
-	rjmp	srxi_end2
+	rjmp	srxi_end
 
 srxi_sberr:
 	ldi	temp,(1<<ICNC1)|(1<<CS10)	;next edge is falling edge
@@ -199,7 +219,7 @@ srxi_sberr:
 	mov	temp,zl
 	rcall	printhex
 #endif
-	rjmp	srxi_end2
+	rjmp	srxi_end
 
 srxi_S2:
 	cpi	temp,2
@@ -207,13 +227,13 @@ srxi_S2:
 
 ; State 2: collect 1-bits
 
-;	lds	temp,srx_lastedge
-;	lds	temp2,srx_lastedge+1
-;	sts	srx_lastedge,zl
-;	sts	srx_lastedge+1,zh
+	lds	temp,srx_lastedge
+	lds	temp2,srx_lastedge+1
+	sts	srx_lastedge,zl
+	sts	srx_lastedge+1,zh
 
-	movw	temp,srx_lastedgel
-	movw	srx_lastedgel,zl
+;	movw	temp,srx_lastedgel
+;	movw	srx_lastedgel,zl
 
 	sub	zl,temp
 	sbc	zh,temp2
@@ -232,12 +252,12 @@ srxi_2l:
 	sts	srx_dr,temp
 	ldi	temp,3
 	sts	srx_state,temp
-	rjmp	srxi_end2
+	rjmp	srxi_end
 	
 srxi_complete1:
 	ldi	temp2,1			;We are in start bit now.
 	sts	srx_state,temp2
-	ldi	temp2,2
+	lds	temp2,srx_char_time
 	sts	srx_char_to,temp2
 	rjmp	srxi_complete
 	
@@ -247,13 +267,13 @@ srxi_S3:
 
 ; State 3: collect 0-bits
 
-;	lds	temp,srx_lastedge
-;	lds	temp2,srx_lastedge+1
-;	sts	srx_lastedge,zl
-;	sts	srx_lastedge+1,zh
+	lds	temp,srx_lastedge
+	lds	temp2,srx_lastedge+1
+	sts	srx_lastedge,zl
+	sts	srx_lastedge+1,zh
 
-	movw	temp,srx_lastedgel
-	movw	srx_lastedgel,zl
+;	movw	temp,srx_lastedgel
+;	movw	srx_lastedgel,zl
 
 	sub	zl,temp
 	sbc	zh,temp2
@@ -272,14 +292,14 @@ srxi_3l:
 	sts	srx_dr,temp
 	ldi	temp,2
 	sts	srx_state,temp
-	rjmp	srxi_end2
+	rjmp	srxi_end
 
 srxi_S4:
 	ldi	zl,(1<<ICNC1)|(1<<CS10)	;next edge is falling edge
 	outm8	TCCR1B,zl
 	ldi	zl,(1<<ICF1)		;clear pending int
 	sts	srx_state,_0		;next state
-	rjmp	srxi_end2
+	rjmp	srxi_end
 
 srxi_complete0:	
 	sts	srx_char_to,_0		;clear timeout
@@ -294,27 +314,25 @@ srxi_complete:
 
 ; Save received character in a circular buffer. Do nothing if buffer overflows.
 
-	lds	zh,rxcount		;if rxcount < RXBUFSIZE
-	cpi	zh,RXBUFSIZE		;   (room for at least 1 char?)
-	brsh	srxi_ov			; 
-	inc	zh			;
-	sts	rxcount,zh		;   rxcount++
-
-	ldi	zl,low(rxfifo)		;  
-	lds	zh,rxidx_w		;
-	add	zl,zh			;
-	inc	zh			;
-	andi	zh,RXBUFMASK		;
-	sts	rxidx_w,zh		;   rxidx_w = ++rxidx_w % RXBUFSIZE
-	ldi	zh,high(rxfifo)		;
-	brcc	PC+2			;
-	inc	zh			;
-	st	z,temp			;   rxfifo[rxidx_w] = char
-srxi_ov:					;endif
-
-srxi_end2:
+	lds	zh,rxcount			;2   if rxcount < RXBUFSIZE
+	cpi	zh,RXBUFSIZE			;1      (room for at least 1 char?)
+	brsh	srxi_ov				;1 
+	inc	zh				;1
+	sts	rxcount,zh			;2      rxcount++
+
+	ldi	zl,low(rxfifo)			;1  
+	lds	zh,rxidx_w			;2
+	add	zl,zh				;1
+	inc	zh				;1
+	andi	zh,RXBUFMASK			;1
+	sts	rxidx_w,zh			;2      rxidx_w = ++rxidx_w % RXBUFSIZE
+	ldi	zh,high(rxfifo)			;1
+	adc	zh,_0				;1
+	st	z,temp				;2      rxfifo[rxidx_w] = char
+srxi_ov:					;=19     endif
+
+srxi_end:
 	pop	temp2
-srxi_end: 
 	pop	zl
 	pop	zh
 	pop	temp
@@ -331,82 +349,76 @@ srxi_end:
 	
 	INTERRUPT OC1Aaddr
 	
-	push	temp
-	in	temp,sreg
-	push	temp
+	push	zl
+	in	zl,sreg
+	push	zl
 	push	zh
 
-	inm8	temp,OCR1AL
+	inm8	zl,OCR1AL
 	inm8	zh,OCR1AH
-	subi	temp,low(-SSER_BIT_TC)
+	subi	zl,low(-SSER_BIT_TC)
 	sbci	zh,high(-SSER_BIT_TC)
 	outm8	OCR1AH,zh
-	outm8	OCR1AL,temp
-	lds	temp,stx_bitcount
-	tst	temp
-	breq	stxi_nxtchar
+	outm8	OCR1AL,zl
+
+	lds	zl,stx_bitcount
+	dec	zl
+	brpl	stxi_nextbit
 	
-	dec	temp
-	sts	stx_bitcount,temp
-	ldi	zh,9				;Start bit?
-	cp	temp,zh
-	ldi	zh,(1<<COM1A1)
-	breq	stxi_0
-	lds	temp,stx_dr
-	sbrs	temp,0
-	ldi	zh,(1<<COM1A1)|(1<<COM1A0)
-	lsr	temp
-	sts	stx_dr,temp
-stxi_0:
-	outm8	TCCR1A,zh
-	pop	zh
-	pop	temp
-	out	sreg,temp
-	pop	temp
-	reti
+; bit counter was 0, more characters?
 
-; more characters?
 stxi_nxtchar:
-	lds	temp,txcount		;if txcount != 0
-	tst	temp			;
-	breq	stxi_dis
+	lds	zl,txcount		;if txcount != 0
+	dec	zl
+	brmi	stxi_dis
+
 ; get next char
-	push	zl
-	dec	temp			;
-	sts	txcount,temp		;   --txcount
+	sts	txcount,zl		;   --txcount
+	push	temp			;
 	ldi	zl,low(txfifo)		;  
 	ldi	zh,high(txfifo)		;
 	lds	temp,txidx_r		;
 	add	zl,temp			;
-	brcc	PC+2			;
-	inc	zh			;
+	adc	zh,_0
 	inc	temp			;
 	andi	temp,TXBUFMASK		;
 	sts	txidx_r,temp		;
 	ld	temp,z
 	com	temp
 	sts	stx_dr,temp
-	ldi	temp,10
+	ldi	temp,9
 	sts	stx_bitcount,temp
-	pop	zl
-	pop	zh
-	pop	temp
-	out	sreg,temp
 	pop	temp
-	reti
+
+	ldi	zh,(1<<COM1A1)
+	rjmp	stxi_ex
 
 ; disable transmitter
 stxi_dis:
-	ldi	temp,(1<<COM1A1)|(1<<COM1A0)
-	outm8	TCCR1A,temp
-	inm8	temp,TIMSK1
-	andi	temp,~(1<<OCIE1A)
-	outm8	TIMSK1,temp
+	inm8	zl,TIMSK1
+	andi	zl,~(1<<OCIE1A)
+	outm8	TIMSK1,zl
+
+	ldi	zh,(1<<COM1A1)|(1<<COM1A0)
+	rjmp	stxi_ex
+
+stxi_nextbit:
+	sts	stx_bitcount,zl
+
+	ldi	zh,(1<<COM1A1)
+	lds	zl,stx_dr
+	sbrs	zl,0
+	ldi	zh,(1<<COM1A1)|(1<<COM1A0)
+	lsr	zl
+	sts	stx_dr,zl
+stxi_ex:
+	outm8	TCCR1A,zh
 	pop	zh
-	pop	temp
-	out	sreg,temp
-	pop	temp
+	pop	zl
+	out	sreg,zl
+	pop	zl
 	reti
+
 ;------------------------------------------------------------------
 
 srx_to:
@@ -424,9 +436,12 @@ srx_to:
 	rcall	uartputc
 #endif
 	lds	temp,srx_dr		;only 0 if timeout after leading edge of start bit.
-	tst	temp
+	tst	temp			; --> break
 	brne	srxto_store
 	sbr	intstat,(1<<i_break)
+	sts	rxcount,_0		;clear rx buffer
+	sts	rxidx_w,_0
+	sts	rxidx_r,_0
 	rjmp	srxto_ov
 
 srxto_store:
@@ -465,27 +480,34 @@ srxto_ov:					;endif
 ;Fetches a char from the buffer to temp. If none available, waits till one is.
 
 uartgetc:
+	push	zh
+	push	zl
+	push	temp2
+ugetc_w:
 	lds	temp,rxcount		;Number of characters in buffer
 	tst	temp
-	breq	uartgetc		;Wait for char
+	breq	ugetc_w			;Wait for char
 	
-	push	zh
-	push	zl
 	ldi	zl,low(rxfifo)
 	ldi	zh,high(rxfifo)
-	lds	temp,rxidx_r
-	add	zl,temp
-	brcc	PC+2
-	inc	zh
-	inc	temp
-	andi	temp,RXBUFMASK
-	sts	rxidx_r,temp
+	lds	temp2,rxidx_r
+	add	zl,temp2
+	adc	zh,_0
+	inc	temp2
+	andi	temp2,RXBUFMASK
 	cli
 	lds	temp,rxcount
-	dec	temp
+	subi	temp,1
+	brcc	ugetc_fin
+	sei
+	rjmp	ugetc_w
+
+ugetc_fin:
 	sts	rxcount,temp
+	sts	rxidx_r,temp2
 	sei
 	ld	temp,z		;don't forget to get the char
+	pop	temp2
 	pop	zl
 	pop	zh
 	ret
@@ -507,8 +529,7 @@ sputc_l:
 	ldi	zh,high(txfifo)		;
 	lds	temp,txidx_w		;
 	add	zl,temp			;
-	brcc	PC+2			;
-	inc	zh			;
+	adc	zh,_0			;
 	inc	temp			;
 	andi	temp,TXBUFMASK		;
 	sts	txidx_w,temp		;   txidx_w = ++txidx_w % TXBUFSIZE
@@ -518,12 +539,23 @@ sputc_l:
 	lds	zh,txcount
 	inc	zh
 	sts	txcount,zh
-	dec	zh
+	cpi	zh,1
 	brne	sputc_e
 ; Enable transmitter
 	inm8	zh,TIMSK1
+	sbrc	zh,OCIE1A
+	rjmp	sputc_e
 	ori	zh,(1<<OCIE1A)
 	outm8	TIMSK1,zh
+
+	inm8	zl,TCNT1L		;
+	inm8	zh,TCNT1H		;
+	adiw	zl,30			;
+	outm8	OCR1AH,zh		;
+	outm8	OCR1AL,zl		;
+	ldi	zl,(1<<OCF1A)
+	outm8	TIFR1,zl
+
 sputc_e:
 	pop	zl
 	out	sreg,zl