Updated John Steggall's software USART in the XPLAINBridge project.

LUFA/ManPages/FutureChanges.txt

@@ -31,6 +31,7 @@
   *      -# Keyboard/Mouse Dual Class Host
   *      -# Multiple-Report HID device
   *      -# Device/Host bridge
+  *      -# PDI Programming Support in the AVRISP Project
   *  - Ports
   *      -# AVR32 UC3B series microcontrollers
   *      -# Atmel ARM7 series microcontrollers

Projects/XPLAINBridge/Lib/SoftUART.S

@@ -2,6 +2,8 @@
 
 	uart_soft
 
+	v0.2
+
 	copyright John Steggall 2009
 
 */
@@ -30,10 +32,8 @@
 */
 
 #include <avr/io.h>
+#include "SoftUARTConf.h"
 
-/* BITLENGTH is the time for a bit cycle worked out at F_CPU / BAUD. Gives a rough but usable figure. Wouldn't like to try
- * anything faster than 9600! */
-#define BITLENGTH 833
 
 #define SFT_TX_EN 7
 
@@ -52,43 +52,59 @@ rxShifter:
 	.byte	0
 rxBitcount:
 	.byte	0
+	
+	.global	status
 status:
 	.byte	0
 
 	.section	.text
 
+
+	.global	RX_PIN_INT
+
 /*********************************************
  * External interrupt
  * 
  * RX pin has gone low.
  */
-	.global	INT0_vect
+RX_PIN_INT:
-
-INT0_vect:
 	push		r16
 	lds		r16,SREG
 	push		r16
 
-	lds		r16,PIND
+#if (RXPORT>=32)
+	lds		r16,RXPORT
 	sbrc		r16,0		// anti glitch
+
+#else
+	sbic		RXPORT,0
+#endif
+
 	rjmp		ignore
 	nop
 	nop
 	nop
 	nop
-	lds		r16,PIND
+
-	sbrc		r16,0		// just make sure
+#if (RXPORT>=32)
+	lds		r16,RXPORT
+	sbrc		r16,0		// anti glitch
+
+#else
+	sbic		RXPORT,0
+#endif
+
 	rjmp		ignore
 
 	push		r17
 
 	// grab timer value
-	lds		r16,TCNT3L		
+	lds		r16,TC_COUNTL		
-	lds		r17,TCNT3H
+	lds		r17,TC_COUNTH
 	
 	// set trigger for RX timer (will need to add a little more though)
-	sts		OCR3CH,r17
+	sts		TC_RX_COMPH,r17
-	sts		OCR3CL,r16
+	sts		TC_RX_COMPL,r16
 	
 	pop		r17
 
@@ -98,13 +114,15 @@ INT0_vect:
 
 
 	// turn off interrupt, will get annoying.
-	cbi		0x1D,0
+	cbi		EXTI_MASK_REG,EXTI_MASK_BIT
 
 	// turn on interrupt on compare match
-	sbi		0x18,OCF3C
+
-	lds		r16,TIMSK3
+	sbi		TC_INTFLAG_REG,TC_RX_IF_BIT		//------------------------
-	ori		r16,(1<<OCIE3C)
+
-	sts		TIMSK3,r16
+	lds		r16,TC_INT_MASK_REG
+	ori		r16,(1<<TC_RX_COMPEN)
+	sts		TC_INT_MASK_REG,r16
 
 ignore:
 	pop		r16
@@ -136,17 +154,23 @@ TIMER3_COMPB_vect:
 
 	lds		r16,txShifter
 
-	lds		r17, PORTD
+#if (TXPORT>=32)
-
+	lds		r17, TXPORT
 	sbrs		r16,0
-	andi		r17,0xFD
+	andi		r17,~(1<<TXPIN)
 	sbrc		r16,0
-	ori		r17,0x02
+	ori		r17,(1<<TXPIN)
+	sts		TXPORT,r17
 
-	sts		PORTD,r17
+#else
+	sbrs		r16,0
+	cbi		TXPORT,TXPIN
+	sbrc		r16,0
+	sbi		TXPORT,TXPIN
 
-	lsr		r16
+#endif
-	ori		r16,0x80
+	sec
+	ror		r16
 
 txout:
 	sts		txShifter,r16
@@ -164,9 +188,9 @@ lastBitTX:
 	ori		r17,SF_UART_TX		// set TXC/DRE flag
 	sts		status,r17
 
-	lds		r16,TIMSK3
+	lds		r16,TC_INT_MASK_REG
-	andi		r16,~(1<<OCIE3B)
+	andi		r16,~(1<<TC_TX_COMPEN)
-	sts		TIMSK3,r16
+	sts		TC_INT_MASK_REG,r16
 
 	rjmp		lastBitOut		// over and out
 
@@ -199,11 +223,27 @@ TIMER3_COMPC_vect:
 	ldi		r18,3			// set counter to 3
 	ldi		r17,0
 
-//	cbi		0x0B,1			// marker
+#ifdef DEBUG
+
+#if RXPORT>64
+	lds		r16,RXPORT
+	andi		r16,~(1<<TXPIN)
+	sts		TXPORT,r16
+#else
+	cbi		TXPORT,TXPIN			// marker
+#endif
+#endif
 
 loopGetBit:
-	lds		r16,PIND			
+
-	sbrc		r16,0
+#if (RXPORT>=32)
+	lds		r16,RXPORT
+	sbrs		r16,RXPIN
+#else			
+	sbic		RXPORT,RXPIN
+
+#endif
+
 	inc		r17
 	dec		r18
 	nop
@@ -212,7 +252,19 @@ loopGetBit:
 	nop
 	brne		loopGetBit
 
-//	sbi		0x0B,1			// marker
+#ifdef DEBUG
+
+#if RXPORT>64
+	lds		r16,RXPORT
+	ori		r16,1<<TXPIN
+	sts		r16
+
+#else
+	sbi		TXPORT,TXPIN			// marker
+
+#endif
+#endif
+
 
 	lds		r16,rxShifter
 	lsr		r16
@@ -226,8 +278,16 @@ skipBitSet:
 
 lastBitRX:
 	lds		r17,status		// store status
-	lds		r16,PIND			// get status of stop bit
+
-	sbrc		r16,0
+#if (RXPORT>=32)
+	lds		r16,RXPORT
+	sbrc		r16,RXPIN
+
+#else
+	sbic		RXPORT,RXPIN	
+
+#endif
+
 	ori		r17,0x02			// set flag if stop bit was high
 	sts		status,r17
 
@@ -237,19 +297,19 @@ lastBitRX:
 
 	// switch interrupt back on to get another go
 
-	sbi		0x1C,0			// clear interrupt flag
+	sbi		EXTI_FLAG_REG,EXTI_MASK_BIT	// clear interrupt flag
-	sbi		0x1D,0			// enable external interrupt 0 (RX)
+	sbi		EXTI_MASK_REG,EXTI_MASK_BIT	// enable external interrupt 0 (RX)
 
 	// switch off rx bit timer
-	lds		r16,TIMSK3
+	lds		r16,TC_INT_MASK_REG
-	andi		r16,~(1<<OCIE3C)
+	andi		r16,~(1<<TC_RX_COMPEN)
-	sts		TIMSK3,r16
+	sts		TC_INT_MASK_REG,r16
 
 	rjmp		lastBitOut		// loud and clear
 
 rx1stbit:
-	lds		r16,TCNT3L
+	lds		r16,TC_COUNTL
-	lds		r17,TCNT3H
+	lds		r17,TC_COUNTH
 
 	subi		r16,lo8(BITLENGTH / 2)
 	sbci		r17,hi8(BITLENGTH / 2)
@@ -259,8 +319,8 @@ rx1stbit:
 	sbci		r17,hi8(0xFFFF - BITLENGTH)
 
 skipOverflow:
-	sts		OCR3CH,r17
+	sts		TC_RX_COMPH,r17
-	sts		OCR3CL,r17
+	sts		TC_RX_COMPL,r17
 	rjmp		lastBitOut
 
 			
@@ -273,12 +333,20 @@ skipOverflow:
 
 SoftUART_Init:
 
-	lds		r18,PORTD
+#if (TXPORT>=32)
+	lds		r18,TXPORT
 	ori		r18,0x02
-	sts		PORTD,r18
+	sts		TXPORT,r18
-	lds		r18,DDRD
+
+	lds		r18,TXDIR_REG
 	ori		r18,0x02
-	sts		DDRD,r18
+	sts		TXDIR_REG,r18
+
+#else
+	sbi		TXPORT,TXPIN
+	sbi		TXDIR_REG,TXPIN
+
+#endif
 
 	ldi		r18,(1<<SFT_TX_EN)|SF_UART_TX
 	sts		status,r18
@@ -290,17 +358,17 @@ SoftUART_Init:
 
 	// Start timer 3
 	ldi		r18,0b00001001			// ctc count mode, clock div 1
-	sts		TCCR3B,r18
+	sts		TC_CTRLB,r18
 
-	// Interrupt on low level INT0
+	// Interrupt on pin change INT0
-	sbi		0x1C,0
+	sbi		EXTI_FLAG_REG,EXTI_MASK_BIT
-	sbi		0x1D,0
+	sbi		EXTI_MASK_REG,EXTI_MASK_BIT
 
 	ret
 
 
 /*********************************************
- * char SoftUART_TxByte(char)
+ * char SoftUART_RxByte(char)
  *
  * starts a byte send and returns the byte to be sent
  */
@@ -309,7 +377,7 @@ SoftUART_Init:
 SoftUART_TxByte:
 	lds		r18,status
 	sbrs		r18,SFT_TX_EN
-	rjmp		uart_putchar_end
+	rjmp		SoftUART_TxByte_end
 
 	andi		r18,0xFE						// clear tx empty flag
 	sts		status,r18
@@ -320,28 +388,35 @@ SoftUART_TxByte:
 	sts		txBitcount,r18
 
 	// grab timer value
-
+	cli									// Atomic section start
-	lds		r18,TCNT3L
+	lds		r18,TC_COUNTL
-	lds		r19,TCNT3H
+	lds		r19,TC_COUNTH
 
 	// drop down tx line for start bit
-	lds		r20, PORTD
+
-	andi		r20,0xFD
+#if (TXPORT>=32)
-	sts		PORTD,r20
+	lds		r20, TXPORT
-	
+	andi		r20,~(1<<TXPIN)
+	sts		TXPORT,r20
+
+#else
+	cbi		TXPORT,TXPIN
+#endif
+
 	// set trigger for tx timer
-	cli
+	sts		TC_TX_COMPH,r19
-	sts		OCR3BH,r19
+	sts		TC_TX_COMPL,r18
-	sts		OCR3BL,r18
+	sei									// Atomic section end
-	sei
 
 	// clear interrupt flag and enable tx interrupt
-	sbi		0x18,OCF3B
-	lds		r18,TIMSK3
-	ori		r18,(1<<OCIE3B)
-	sts		TIMSK3,r18
 
-uart_putchar_end:
+	sbi		TC_INTFLAG_REG,TC_TX_IF_BIT
+
+	lds		r18,TC_INT_MASK_REG
+	ori		r18,(1<<TC_TX_COMPEN)
+	sts		TC_INT_MASK_REG,r18
+
+SoftUART_TxByte_end:
 	ret
 
 

Projects/XPLAINBridge/Lib/SoftUART.h

@@ -2,6 +2,8 @@
 
 	soft_uart
 
+	v0.2
+
 	Copyright John Steggall 2009
 
 */
@@ -30,17 +32,31 @@
 */
 
 /* 
-  Specifically designed for the xplain board, other uses could be made by furkling through the code
+  Specifically designed for the xplain board, other uses could be made by adjusting uart_soft_conf.h
-  and replacing the port and pin assignments. Also relies on and external interupt to detect the low
+  replacing the port, pin and timer assignments. Also relies on and external interupt to detect the low
   level of the start bit, in this case INT0.
   Always configured to 9600baud. Can be changed by setting the BITLENGTH define to F_CPU/(desired baud)
   code may need optimising when getting any faster to sample the bit in the correct place. No 
   compensation has been made for the response time of the int routine.
+
+  Note: Configured to use 16bit timers.
+
+ */
+
+/* Changes 
+ *
+ * v0.2
+ * - Added configuration file to ease pain of setup for different hardware configuration
+ * - Changed bit access for ports that can be accessed directly
+ * - Fixed atomic section in uart_init to encompass counter read
  */
 
 #ifndef UART_SOFT_H
 #define UART_SOFT_H
 
+	/* status */
+	extern uint8_t status;
+
 	/*  initialises software uart and enables transmit */
 	extern void SoftUART_Init(void);
 

Projects/XPLAINBridge/Lib/SoftUARTConf.h

@@ -0,0 +1,75 @@
+/*
+
+	soft_uart
+
+	v0.2
+
+	Copyright John Steggall 2009
+
+*/
+
+/*
+  Copyright 2009  John Steggall (steggall.j@gmail.com)
+
+  Permission to use, copy, modify, and distribute this software
+  and its documentation for any purpose and without fee is hereby
+  granted, provided that the above copyright notice appear in all
+  copies and that both that the copyright notice and this
+  permission notice and warranty disclaimer appear in supporting
+  documentation, and that the name of the author not be used in
+  advertising or publicity pertaining to distribution of the
+  software without specific, written prior permission.
+
+  The author disclaim all warranties with regard to this
+  software, including all implied warranties of merchantability
+  and fitness.  In no event shall the author be liable for any
+  special, indirect or consequential damages or any damages
+  whatsoever resulting from loss of use, data or profits, whether
+  in an action of contract, negligence or other tortious action,
+  arising out of or in connection with the use or performance of
+  this software.
+*/
+
+#ifndef UART_SOFT_CONF
+#define UART_SOFT_CONF
+
+	#define BITLENGTH 833						// Length of data bit, worked out by F_CPU/desired baud
+
+	#define TXPIN 1								// Port pin TX is connected to
+	#define RXPIN 0								// Port pin RX is connected to
+
+	/* PORT setup */
+	#define RXPORT			0x09				// RX port selection
+	#define TXPORT 		0x0B					// TX port selection
+	#define TXDIR_REG 		0x0A				// Data direction port for TX pin
+
+	/* RX pin setup */
+	#define EXTI_FLAG_REG 	0x1C
+	#define EXTI_MASK_REG 	0x1D
+	#define EXTI_MASK_BIT 	0
+
+	#define RX_PIN_INT		INT0_vect			// external interrupt vector for RX pin
+	#define RX_INT_vect		TIMER3_COMPC_vect	// interrupt vector for OCRnC
+	#define TX_INT_vect		TIMER3_COMPB_vect	// interrupt vector for OCRnB
+
+	#define TC_INT_MASK_REG	TIMSK3				// interrupt timer mask register for timer(n)
+	#define TC_COUNTL		TCNT3L				// count high register for timer(n)
+	#define TC_COUNTH		TCNT3H				// count low register for timer(n)
+
+	/* Reciever setup */
+	#define TC_RX_COMPEN	OCIE3C				// interrupt enable for OCRnC (RX bit timer)
+	#define TC_RX_COMPH		OCR3CH				// OCRnC compare match high register
+	#define TC_RX_COMPL		OCR3CL				// OCRnC compare match high register
+
+	/* Transmitter setup */
+	#define TC_TX_COMPEN	OCIE3B				// interrupt enable for OCRnB (TX bit timer)
+	#define TC_TX_COMPH		OCR3BH				// OCRnB compare match high register
+	#define TC_TX_COMPL		OCR3BL				// OCRnB compare match low register
+
+	#define TC_CTRLB		TCCR3B				// timer(n) control register B
+
+	#define TC_INTFLAG_REG	0x18				// timer(n) interupt flag register
+	#define TC_TX_IF_BIT	OCIE3B				// timer(n) interrupt flag bit for OCRnB
+	#define TC_RX_IF_BIT	OCIE3C				// timer(n) interrupt flag bit for OCRnC
+
+#endif