examples: Working i2c master test board

Write a few bytes to an i2c eeprom, read them back...

Signed-off-by: Michel Pollet <[email protected]>

examples/board_i2ctest/Makefile

@@ -37,10 +37,12 @@ all: obj atmega48_${target}.axf ${target}
 include ${simavr}/Makefile.common
 
 atmega48_${target}.axf: atmega48_${target}.c
+atmega48_${target}.axf: avr_twi_master.c avr_twi_master.h
 
 board = ${OBJ}/${target}.elf
 
 ${board} : ${OBJ}/${target}.o
+${board} : ${OBJ}/i2c_eeprom.o
 ${board} : ${simavr}/simavr/${OBJ}/libsimavr.a
 
 ${target}: ${board}

examples/board_i2ctest/README

@@ -0,0 +1,15 @@
+
+This contains a sample program to demonstrate the use of simavr
+using 'custom' code, and own "peripherals". It shows how it is
+possible to "hook" code to the AVR pins, and also how to make
+"peripherals" and also hook them up to AVR pins.
+
+This demo demonstrate how to write a i2c/twi "peripheral" and hook it to
+an AVR, and then run a firmware that behaves as a TWI "master" to talk to it.
+
+The code uses a generic i2c "eeprom" were the AVR writes some bytes,
+then read them again. The AVR code is based on the Atmel reference
+implementation, with quite a few changes to make it more functional.
+
+Thid "board" doesn't use opengl, the eeprom will display what the
+transactions are.

examples/board_i2ctest/atmega48_i2ctest.c

@@ -27,7 +27,7 @@
 #include "avr_mcu_section.h"
 AVR_MCU(F_CPU, "atmega48");
 
-#include "avr_twi_master.c"
+#include "avr_twi_master.h"
 
 #include <stdio.h>
 

examples/board_i2ctest/avr_twi_master.c

@@ -23,6 +23,8 @@
 *
 ****************************************************************************/
 
+#include <avr/io.h>
+#include <avr/interrupt.h>
 #include "avr_twi_master.h"
 
 //static unsigned char TWI_buf[ TWI_BUFFER_SIZE ];    // Transceiver buffer
@@ -162,7 +164,12 @@ ISR( TWI_vect )
         if (TWI_sendStop)
         	TWCR = (1<<TWEN)|                                 // TWI Interface enabled
                (0<<TWIE)|(1<<TWINT)|                      // Disable TWI Interrupt and clear the flag
-               (0<<TWEA)|(0<<TWSTA)|(1<<TWSTO)|           // Initiate a STOP condition?
+               (0<<TWEA)|(0<<TWSTA)|(1<<TWSTO)|           // Initiate a STOP condition
+               (0<<TWWC);                                 //
+        else
+        	TWCR = (1<<TWEN)|                                 // TWI Interface enabled
+               (0<<TWIE)|(1<<TWINT)|                      // Disable TWI Interrupt and clear the flag
+               (0<<TWEA)|(0<<TWSTA)|(0<<TWSTO)|           // DO NOT Initiate a STOP condition
                (0<<TWWC);                                 //
       }
       break;

examples/board_i2ctest/i2ctest.c

@@ -19,8 +19,6 @@
 	along with simavr.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-
-
 #include <stdlib.h>
 #include <stdio.h>
 #include <libgen.h>
@@ -31,106 +29,7 @@
 #include "sim_elf.h"
 #include "sim_gdb.h"
 #include "sim_vcd_file.h"
-
-
-typedef struct i2c_eeprom_t {
-	avr_irq_t *	irq;		// irq list
-	uint8_t addr_base;
-	uint8_t addr_mask;
-
-	uint8_t selected;		// selected address
-	int index;	// byte index
-
-	uint16_t reg_addr;		// read/write address register
-	int size;				// also implies the address size, one or two byte
-	uint8_t ee[4096];
-} i2c_eeprom_t;
-
-#include <string.h>
-
-/*
- * called when a RESET signal is sent
- */
-static void
-i2c_eeprom_in_hook(
-		struct avr_irq_t * irq,
-		uint32_t value,
-		void * param)
-{
-	i2c_eeprom_t * p = (i2c_eeprom_t*)param;
-	avr_twi_msg_irq_t v;
-	v.u.v = value;
-
-	if (v.u.twi.msg & TWI_COND_STOP) {
-		if (p->selected) {
-			// it was us !
-			printf("eeprom received stop\n");
-		}
-		p->selected = 0;
-		p->index = 0;
-		p->reg_addr = 0;
-	}
-	if (v.u.twi.msg & TWI_COND_START) {
-		p->selected = 0;
-		p->index = 0;
-		if ((p->addr_base & p->addr_mask) == (v.u.twi.addr & p->addr_mask)) {
-			// it's us !
-			p->selected = v.u.twi.addr;
-			avr_raise_irq(p->irq + TWI_IRQ_MISO,
-					avr_twi_irq_msg(TWI_COND_ACK, p->selected, 1));
-		}
-	}
-	if (p->selected) {
-		if (v.u.twi.msg & TWI_COND_WRITE) {
-			printf("eeprom write %02x\n", v.u.twi.data);
-			// address size is how many bytes we use for address register
-			avr_raise_irq(p->irq + TWI_IRQ_MISO,
-					avr_twi_irq_msg(TWI_COND_ACK, p->selected, 1));
-			int addr_size = p->size > 256 ? 2 : 1;
-			if (p->index < addr_size) {
-				p->reg_addr |= (v.u.twi.data << (p->index * 8));
-				printf("eeprom set address to %04x\n", p->reg_addr);
-			} else {
-				printf("eeprom WRITE data %04x: %02x\n", p->reg_addr, v.u.twi.data);
-				p->ee[p->reg_addr++] = v.u.twi.data;
-			}
-			p->reg_addr &= (p->size -1);
-			p->index++;
-		}
-		if (v.u.twi.msg & TWI_COND_READ) {
-			printf("eeprom READ data %04x: %02x\n", p->reg_addr, p->ee[p->reg_addr]);
-			uint8_t data = p->ee[p->reg_addr++];
-			avr_raise_irq(p->irq + TWI_IRQ_MISO,
-					avr_twi_irq_msg(TWI_COND_READ, p->selected, data));
-			p->reg_addr &= (p->size -1);
-			p->index++;
-		}
-	}
-}
-
-static const char * _ee_irq_names[2] = {
-		[TWI_IRQ_MISO] = "8>eeprom.out",
-		[TWI_IRQ_MOSI] = "32<eeprom.in",
-};
-
-void
-i2c_eeprom_init(
-		struct avr_t * avr,
-		i2c_eeprom_t * p,
-		uint8_t addr,
-		uint8_t mask,
-		uint8_t * data,
-		size_t size)
-{
-	memset(p, 0, sizeof(p));
-	memset(p->ee, 0xff, sizeof(p->ee));
-	p->irq = avr_alloc_irq(&avr->irq_pool, 0, 2, _ee_irq_names);
-	avr_irq_register_notify(p->irq + TWI_IRQ_MOSI, i2c_eeprom_in_hook, p);
-
-	p->size = size > sizeof(p->ee) ? sizeof(p->ee) : size;
-	if (data)
-		memcpy(p->ee, data, p->size);
-}
+#include "i2c_eeprom.h"
 
 avr_t * avr = NULL;
 avr_vcd_t vcd_file;
@@ -141,9 +40,7 @@ int main(int argc, char *argv[])
 {
 	elf_firmware_t f;
 	const char * fname =  "atmega48_i2ctest.axf";
-	char path[256];
 
-	sprintf(path, "%s/%s", dirname(argv[0]), fname);
 	printf("Firmware pathname is %s\n", fname);
 	elf_read_firmware(fname, &f);
 
@@ -160,13 +57,8 @@ int main(int argc, char *argv[])
 	// initialize our 'peripheral'
 	i2c_eeprom_init(avr, &ee, 0xa0, 0xfe, NULL, 1024);
 
-	// "connect" the IRQs of the button to the port pin of the AVR
-	avr_connect_irq(
-		ee.irq + TWI_IRQ_MISO,
-		avr_io_getirq(avr, AVR_IOCTL_TWI_GETIRQ(0), TWI_IRQ_MISO));
-	avr_connect_irq(
-		avr_io_getirq(avr, AVR_IOCTL_TWI_GETIRQ(0), TWI_IRQ_MOSI),
-		ee.irq + TWI_IRQ_MOSI );
+	i2c_eeprom_attach(avr, &ee, AVR_IOCTL_TWI_GETIRQ(0));
+	ee.verbose = 1;
 
 	// even if not setup at startup, activate gdb if crashing
 	avr->gdb_port = 1234;
@@ -187,8 +79,7 @@ int main(int argc, char *argv[])
 		avr_io_getirq(avr, AVR_IOCTL_TWI_GETIRQ(0), TWI_IRQ_STATUS), 8 /* bits */ ,
 		"TWSR" );
 
-	printf( "Demo launching:\n"
-			);
+	printf( "Demo launching:\n");
 
 	while (1)
 		avr_run(avr);