AVR ISP adapter (avr109/910 compatible, using ATmega16)
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/***************************************************************************
* C based avr910 / avr109 ISP Adapter *
* *
* Copyright (C) 2006 - 20011 by Olaf Rempel *
* razzor AT kopf MINUS tisch DOT de *
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; version 2 of the License, *
* *
* This program is distributed in the hope that it will be useful, *
* but WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
* GNU General Public License for more details. *
* *
* You should have received a copy of the GNU General Public License *
* along with this program; if not, write to the *
* Free Software Foundation, Inc., *
* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. *
***************************************************************************/
#include <avr/io.h>
#include <avr/eeprom.h>
#include <avr/pgmspace.h>
#include <avr/interrupt.h>
#include <string.h>
#include <util/crc16.h>
#define ARRAY_SIZE(x) (sizeof(x) / sizeof(*x))
/*
* using ATmega16 @7.3728MHz:
* Fuse H: 0xDA (512 words bootloader, jtag disabled)
* Fuse L: 0xFF (ext. Crystal)
*/
#define F_CPU 7372800
#define BAUDRATE 115200
#define TIMER_RELOAD (0xFF - 72) /* 10ms @7.3728MHz */
#define ISP_RESET PORTB1 /* to target */
#define ISP_LED PORTB3 /* low active */
#define ISP_MOSI PORTB5 /* to target */
#define ISP_MISO PORTB6 /* to target */
#define ISP_SCK PORTB7 /* to target */
#define RESET_IN PORTD3 /* high active */
#include <util/delay.h>
#define UART_CALC_BAUDRATE(baudRate) (((uint32_t)F_CPU) / (((uint32_t)baudRate)*16) -1)
/* F_CPU /4 (1.8432MHz) */
#define SPI_MODE4 ((1<<SPE) | (1<<MSTR))
/* F_CPU /16 (460.8kHz) */
#define SPI_MODE3 ((1<<SPE) | (1<<MSTR) | (1<<SPR1))
/* F_CPU /64 (115.2kHz) */
#define SPI_MODE2 ((1<<SPE) | (1<<MSTR) | (1<<SPR0))
/* F_CPU /128 (57.6kHz) */
#define SPI_MODE1 ((1<<SPE) | (1<<MSTR) | (1<<SPR1) | (1<<SPR0))
#define POLL_00 0x01 /* value 0x00 can not be polled from flash/eeprom */
#define POLL_7F 0x02 /* value 0x7F can not be polled from flash/eeprom */
#define POLL_80 0x04 /* value 0x80 can not be polled from flash/eeprom */
#define POLL_FF 0x08 /* value 0xFF can not be polled from flash/eeprom */
struct _device {
uint8_t sig[3]; /* device signature */
uint8_t devcode; /* avr910 device code */
uint16_t pagemask; /* pagemask */
uint16_t flags; /* quirks for this device */
};
static struct _device device;
static struct _device devices[] PROGMEM = {
{ { 0x1E, 0x90, 0x01 }, 0x13, 0x00, POLL_00 | POLL_FF }, /* at90s1200 */
{ { 0x1E, 0x91, 0x01 }, 0x20, 0x00, POLL_7F | POLL_80 | POLL_FF }, /* at90s2313 */
{ { 0x1E, 0x91, 0x08 }, 0x20, 0x0F, POLL_FF }, /* tiny25 (at90s2313 devcode) */
{ { 0x1E, 0x91, 0x09 }, 0x5E, 0x0F, POLL_FF }, /* tiny26 */
{ { 0x1E, 0x91, 0x0A }, 0x5E, 0x0F, POLL_FF }, /* tiny2313 (tiny26 devcode) */
{ { 0x1E, 0x91, 0x0B }, 0x20, 0x0F, POLL_FF }, /* tiny24 (at90s2313 devcode) */
{ { 0x1E, 0x92, 0x06 }, 0x20, 0x1F, POLL_FF }, /* tiny45 (at90s2313 devcode) */
{ { 0x1E, 0x92, 0x07 }, 0x20, 0x1F, POLL_FF }, /* tiny44 (at90s2313 devcode) */
{ { 0x1E, 0x93, 0x01 }, 0x38, 0x00, POLL_7F | POLL_80 | POLL_FF }, /* at90s8515 */
{ { 0x1E, 0x93, 0x07 }, 0x76, 0x1F, POLL_00 | POLL_FF }, /* mega8 */
{ { 0x1E, 0x93, 0x0A }, 0xFF, 0x1F, POLL_FF }, /* mega88 (no devcode) */
{ { 0x1E, 0x93, 0x0B }, 0x20, 0x1F, POLL_FF }, /* tiny85 (at90s2313 devcode) */
{ { 0x1E, 0x93, 0x0C }, 0x20, 0x1F, POLL_FF }, /* tiny84 (at90s2313 devcode) */
{ { 0x1E, 0x94, 0x03 }, 0x74, 0x3F, POLL_FF }, /* mega16 */
{ { 0x1E, 0x94, 0x06 }, 0xFF, 0x3F, POLL_FF }, /* mega168 (no devcode) */
{ { 0x1E, 0x95, 0x02 }, 0x72, 0x3F, POLL_FF }, /* mega32 */
{ { 0x1E, 0x96, 0x02 }, 0x45, 0x7F, POLL_FF }, /* mega64 */
{ { 0x1E, 0x96, 0x09 }, 0x74, 0x7F, POLL_FF }, /* mega644 (mega16 devcode) */
{ { 0x1E, 0x96, 0x0A }, 0x74, 0x7F, POLL_FF }, /* mega644p (mega16 devcode) */
{ { 0x1E, 0x97, 0x01 }, 0x41, 0x7F, POLL_7F | POLL_80 | POLL_FF }, /* mega103 */
{ { 0x1E, 0x97, 0x02 }, 0x43, 0x7F, POLL_FF }, /* mega128 */
};
#define EV_NONE 0
#define EV_STATE_ENTER 1
#define EV_BUTTON_PRESSED 2
#define EV_BUTTON_RELEASED 3
#define EV_TIMEOUT 4
#define STATE_IDLE 0 /* nothing */
#define STATE_PRESSED 1 /* reset_in pressed, generating 50ms isp_reset pulse */
#define STATE_PRESSED2 2 /* reset_in still pressed, isp_reset pulse complete */
#define STATE_SPEED1 3 /* spi speed setting 1 */
#define STATE_SPEED2 4
#define STATE_SPEED3 5
#define STATE_SPEED4 6
#define STATE_NVRAM_STORE 7 /* start nvram_write (internal state) */
#define LED_OFF 0x00
#define LED_SLOW 0x20
#define LED_FAST 0x08
#define LED_ON 0x80
#define LED_SPEED1 0x20
#define LED_SPEED2 0x10
#define LED_SPEED3 0x08
#define LED_SPEED4 0x04
#define CMD_PROG_ENABLE_1 0xAC
#define CMD_PROG_ENABLE_2 0x53
#define CMD_CHIP_ERASE_1 0xAC
#define CMD_CHIP_ERASE_2 0x80
#define CMD_POLL_BUSY_1 0xF0 /* not used */
#define CMD_POLL_BUSY_2 0x00 /* not used */
#define CMD_LOAD_EADDR_1 0x4D /* not used */
#define CMD_LOAD_EADDR_2 0x00 /* not used */
#define CMD_LOAD_FLASH_HI 0x48
#define CMD_LOAD_FLASH_LO 0x40
#define CMD_LOAD_EEPROM_PAGE 0xC1 /* not used */
#define CMD_READ_FLASH_LO 0x20
#define CMD_READ_FLASH_HI 0x28
#define CMD_READ_EEPROM 0xA0
#define CMD_READ_LOCK_1 0x58
#define CMD_READ_LOCK_2 0x00
#define CMD_READ_SIG_1 0x30
#define CMD_READ_SIG_2 0x00
#define CMD_READ_FUSE_1 0x50
#define CMD_READ_FUSE_2 0x00
#define CMD_READ_FUSE_H_1 0x58
#define CMD_READ_FUSE_H_2 0x08
#define CMD_READ_FUSE_E_1 0x50
#define CMD_READ_FUSE_E_2 0x08
#define CMD_READ_CAL 0x38 /* not used */
#define CMD_WRITE_FLASH_PAGE 0x4C
#define CMD_WRITE_EEPROM 0xC0
#define CMD_WRITE_EEPROM_PAGE 0xC2 /* not used */
#define CMD_WRITE_LOCK_1 0xAC
#define CMD_WRITE_LOCK_2 0xE0
#define CMD_WRITE_FUSE_1 0xAC
#define CMD_WRITE_FUSE_2 0xA0
#define CMD_WRITE_FUSE_H_1 0xAC /* not used */
#define CMD_WRITE_FUSE_H_2 0xA8 /* not used */
#define CMD_WRITE_FUSE_E_1 0xAC /* not used */
#define CMD_WRITE_FUSE_E_2 0xA4 /* not used */
struct _nvdata {
uint8_t nvram_size; /* first */
uint8_t spi_mode;
uint16_t nvram_crc; /* last */
};
static uint8_t nvram_write_pos;
static struct _nvdata nvram_data;
static struct _nvdata nvram_eeprom EEMEM;
static struct _nvdata nvram_defaults PROGMEM = { .spi_mode = SPI_MODE4 };
/* create crc and store nvram data to eeprom */
static void nvram_start_write(void)
{
uint8_t i;
uint16_t crc = 0x0000;
uint8_t *tmp = (uint8_t *)&nvram_data;
nvram_data.nvram_size = sizeof(struct _nvdata);
for (i = 0; i < sizeof(struct _nvdata) -2; i++) {
crc = _crc_ccitt_update(crc, *tmp++);
}
nvram_data.nvram_crc = crc;
nvram_write_pos = 0;
EEARL = nvram_write_pos;
EEARH = 0x00;
EEDR = ((uint8_t *)&nvram_data)[nvram_write_pos++];
EECR |= (1<<EEMWE);
EECR |= (1<<EEWE);
EECR |= (1<<EERIE);
}
/* store nvram data to eeprom */
ISR(EE_RDY_vect)
{
if (nvram_write_pos < sizeof(struct _nvdata)) {
EEARL = nvram_write_pos;
EEARH = 0x00;
EEDR = ((uint8_t *)&nvram_data)[nvram_write_pos++];
EECR |= (1<<EEMWE);
EECR |= (1<<EEWE);
EECR |= (1<<EERIE);
} else {
EECR &= ~(1<<EERIE);
}
}
/* read nvram from eeprom and check crc */
static void nvram_read(void)
{
uint8_t i;
uint16_t crc = 0x0000;
uint8_t *tmp = (uint8_t *)&nvram_data;
eeprom_read_block(&nvram_data, &nvram_eeprom, sizeof(struct _nvdata));
for (i = 0; i < sizeof(struct _nvdata); i++) {
crc = _crc_ccitt_update(crc, *tmp++);
}
/* if nvram content is invalid, overwrite with defaults */
if ((nvram_data.nvram_size != sizeof(struct _nvdata)) || (crc != 0x0000)) {
memcpy_P(&nvram_data, &nvram_defaults, sizeof(struct _nvdata));
nvram_start_write();
}
}
static volatile uint8_t led_mode;
static uint8_t last_cmd;
static uint8_t last_val;
static uint16_t last_addr;
/* Send one byte to PC */
static void ser_send(uint8_t data)
{
loop_until_bit_is_set(UCSRA, UDRIE);
UDR = data;
}
/* Receive one byte from PC */
static uint8_t ser_recv(void)
{
loop_until_bit_is_set(UCSRA, RXC);
return UDR;
}
/* Send one byte to target, and return received one */
static uint8_t spi_rxtx(uint8_t val)
{
SPDR = val;
loop_until_bit_is_set(SPSR, SPIF);
return SPDR;
}
/* Control reset and SPI lines */
static void set_reset(uint8_t mode)
{
if (mode) {
/* ISP_SCK, ISP_MOSI and ISP_RESET are inputs */
DDRB &= ~((1<<ISP_SCK) | (1<<ISP_MOSI) | (1<<ISP_RESET));
PORTB |= (1<<ISP_RESET);
} else {
/*ISP_SCK, ISP_MOSI and ISP_RESET are outputs, set ISP_RESET low */
DDRB |= ((1<<ISP_SCK) | (1<<ISP_MOSI) | (1<<ISP_RESET));
PORTB &= ~(1<<ISP_RESET);
}
}
/* writes a byte to target flash/eeprom */
static void mem_write(uint8_t cmd, uint16_t addr, uint8_t val)
{
spi_rxtx(cmd);
spi_rxtx(addr >> 8);
spi_rxtx(addr & 0xFF);
spi_rxtx(val);
/* remember values for polling */
last_cmd = cmd;
last_addr = addr;
last_val = val;
}
/* read a byte from target flash/eeprom */
static uint8_t mem_read(uint8_t cmd, uint16_t addr)
{
spi_rxtx(cmd);
spi_rxtx(addr >> 8);
spi_rxtx(addr & 0xFF);
return spi_rxtx(0x00);
}
/* wait until byte/page is written to target memory */
static void poll(void)
{
uint8_t cmd, val, poll = 0xFF;
if (((last_val == 0x00) && (device.flags & POLL_00)) ||
((last_val == 0x7F) && (device.flags & POLL_7F)) ||
((last_val == 0x80) && (device.flags & POLL_80)) ||
((last_val == 0xFF) && (device.flags & POLL_FF))
) {
/* wait default time */
_delay_ms(15);
return;
}
if (last_cmd == CMD_WRITE_EEPROM) {
cmd = CMD_READ_EEPROM;
} else {
/* CMD_WRITE_FLASH -> CMD_READ_FLASH */
cmd = (last_cmd & 0x08) | 0x20;
}
/* poll until we get correct value */
do {
val = mem_read(cmd, last_addr);
} while ((val != last_val) && poll--);
}
static void mem_pagewrite(uint16_t addr)
{
spi_rxtx(CMD_WRITE_FLASH_PAGE);
spi_rxtx(addr >> 8);
spi_rxtx(addr & 0xFF);
spi_rxtx(0x00);
poll();
}
static void cmdloop(void) __attribute__ ((noreturn));
static void cmdloop(void)
{
static uint8_t page_buf[256];
uint16_t addr = 0;
/* disable ISP_RESET */
set_reset(1);
while (1) {
switch (ser_recv()) {
/* Enter programming mode */
case 'P': {
uint8_t sync, count = 0x20;
led_mode = LED_ON;
do {
set_reset(1);
_delay_ms(50);
set_reset(0);
_delay_ms(50);
spi_rxtx(CMD_PROG_ENABLE_1);
spi_rxtx(CMD_PROG_ENABLE_2);
sync = spi_rxtx(0x00);
spi_rxtx(0x00);
} while (sync != CMD_PROG_ENABLE_2 && count--);
memset(&device, 0x00, sizeof(struct _device));
if (sync == CMD_PROG_ENABLE_2) {
uint8_t i;
for (i = 0; i < 3; i++) {
device.sig[i] = mem_read(CMD_READ_SIG_1, (CMD_READ_SIG_2 << 8) | i);
}
for (i = 0; i < ARRAY_SIZE(devices); i++) {
if (memcmp_P(device.sig, devices[i].sig, sizeof(device.sig)) == 0) {
memcpy_P(&device, &devices[i], sizeof(struct _device));
break;
}
}
}
ser_send('\r');
break;
}
/* Autoincrement address */
case 'a':
ser_send('Y');
break;
/* Set address */
case 'A':
addr = (ser_recv() << 8);
addr |= ser_recv();
ser_send('\r');
break;
/* Write program memory, low byte */
case 'c':
led_mode = LED_FAST;
mem_write(CMD_LOAD_FLASH_LO, addr, ser_recv());
/* poll on byte addressed targets */
if (device.pagemask == 0x00) {
poll();
}
ser_send('\r');
break;
/* Write program memory, high byte */
case 'C':
led_mode = LED_FAST;
mem_write(CMD_LOAD_FLASH_HI, addr, ser_recv());
/* poll on byte addressed targets */
if (device.pagemask == 0x00) {
poll();
}
addr++;
ser_send('\r');
break;
/* Issue Page Write */
case 'm':
led_mode = LED_FAST;
mem_pagewrite(last_addr);
ser_send('\r');
break;
/* Read Lock Bits */
case 'r':
ser_send(mem_read(CMD_READ_LOCK_1, CMD_READ_LOCK_2 << 8));
ser_send('\r');
break;
/* Read program memory */
case 'R':
led_mode = LED_SLOW;
ser_send(mem_read(CMD_READ_FLASH_HI, addr));
ser_send(mem_read(CMD_READ_FLASH_LO, addr));
addr++;
break;
/* Read data memory */
case 'd':
led_mode = LED_SLOW;
ser_send(mem_read(CMD_READ_EEPROM, addr));
addr++;
break;
/* Write data memory */
case 'D':
led_mode = LED_FAST;
mem_write(CMD_WRITE_EEPROM, addr, ser_recv());
poll();
addr++;
ser_send('\r');
break;
/* Chip erase */
case 'e':
spi_rxtx(CMD_CHIP_ERASE_1);
spi_rxtx(CMD_CHIP_ERASE_2);
spi_rxtx(0x00);
spi_rxtx(0x00);
_delay_ms(10);
ser_send('\r');
break;
/* Write lock bits */
case 'l': {
uint8_t val = ser_recv();
spi_rxtx(CMD_WRITE_LOCK_1);
spi_rxtx(CMD_WRITE_LOCK_2);
spi_rxtx(0x00);
spi_rxtx(val);
_delay_ms(10);
ser_send('\r');
break;
}
/* Read fusebits */
case 'F':
ser_send(mem_read(CMD_READ_FUSE_1, CMD_READ_FUSE_2 << 8));
break;
/* Read high fusebits */
case 'N':
ser_send(mem_read(CMD_READ_FUSE_H_1, CMD_READ_FUSE_H_2 << 8));
break;
/* Read extended fusebits */
case 'Q':
ser_send(mem_read(CMD_READ_FUSE_E_1, CMD_READ_FUSE_E_2 << 8));
break;
/* Leave programming mode */
case 'L':
/* Exit Bootloader */
case 'E':
set_reset(1);
led_mode = LED_OFF;
ser_send('\r');
break;
/* Select device type */
case 'T': {
ser_recv(); // ignore
ser_send('\r');
break;
}
/* Read signature bytes */
case 's': {
uint8_t i = 2;
do {
ser_send(device.sig[i]);
} while (i--);
break;
}
/* Return supported device codes */
case 't': {
uint8_t limit = 0x00;
while (1) {
uint8_t i;
uint8_t search = 0xFF;
for (i = 0; i < ARRAY_SIZE(devices); i++) {
uint8_t devcode = pgm_read_byte(&devices[i].devcode);
if ((devcode > limit) && (devcode < search)) {
search = devcode;
}
}
if (search == 0xFF)
break;
ser_send(search);
limit = search;
}
ser_send(0x00);
break;
}
/* Return software identifier */
case 'S':
ser_send('A');
ser_send('V');
ser_send('R');
ser_send('-');
ser_send('I');
ser_send('S');
ser_send('P');
break;
/* Return software version */
case 'V':
ser_send('3');
ser_send('8');
break;
/* Return hardware version */
case 'v':
ser_send('1');
ser_send('2');
break;
/* Return programmer type */
case 'p':
ser_send('S');
break;
/* Set LED */
case 'x':
ser_recv();
led_mode = LED_ON;
break;
/* Clear LED */
case 'y':
ser_recv();
led_mode = LED_OFF;
break;
/* Report Block write Mode */
case 'b': {
ser_send('Y');
ser_send(sizeof(page_buf) >> 8);
ser_send(sizeof(page_buf) & 0xFF);
break;
}
/* Block Write */
case 'B': {
uint16_t size, i;
uint8_t type;
led_mode = LED_FAST;
size = ser_recv() << 8;
size |= ser_recv();
type = ser_recv();
for (i = 0; i < size; i++)
page_buf[i] = ser_recv();
if (type == 'F') {
for (i = 0; i < size; i += 2) {
mem_write(CMD_LOAD_FLASH_LO, addr, page_buf[i]);
mem_write(CMD_LOAD_FLASH_HI, addr, page_buf[i+1]);
addr++;
if ((addr & device.pagemask) == 0x00) {
mem_pagewrite(last_addr);
}
}
if (size != sizeof(page_buf)) {
mem_pagewrite(last_addr);
}
} else if (type == 'E') {
for (i = 0; i < size; i++) {
mem_write(CMD_WRITE_EEPROM, addr, page_buf[i]);
poll();
addr++;
}
}
ser_send('\r');
break;
}
/* Block Read */
case 'g': {
uint16_t size, i;
uint8_t type;
led_mode = LED_SLOW;
size = ser_recv() << 8;
size |= ser_recv();
type = ser_recv();
if (type == 'F') {
for (i = 0; i < size; i += 2) {
ser_send(mem_read(CMD_READ_FLASH_LO, addr));
ser_send(mem_read(CMD_READ_FLASH_HI, addr));
addr++;
}
} else if (type == 'E') {
for (i = 0; i < size; i++) {
ser_send(mem_read(CMD_READ_EEPROM, addr));
addr++;
}
}
break;
}
/* Write fusebits */
case 'f': {
uint8_t val = ser_recv();
spi_rxtx(CMD_WRITE_FUSE_1);
spi_rxtx(CMD_WRITE_FUSE_2);
spi_rxtx(0x00);
spi_rxtx(val);
_delay_ms(10);
ser_send('\r');
break;
}
/* Universial command */
case ':': {
uint8_t val[3];
val[0] = ser_recv();
val[1] = ser_recv();
val[2] = ser_recv();
spi_rxtx(val[0]);
spi_rxtx(val[1]);
ser_send(spi_rxtx(val[2]));
_delay_ms(10);
ser_send('\r');
break;
}
/* New universal command */
case '.': {
uint8_t val[4];
val[0] = ser_recv();
val[1] = ser_recv();
val[2] = ser_recv();
val[3] = ser_recv();
spi_rxtx(val[0]);
spi_rxtx(val[1]);
spi_rxtx(val[2]);
ser_send(spi_rxtx(val[3]));
_delay_ms(10);
ser_send('\r');
break;
}
/* ESC */
case 0x1B:
break;
default:
ser_send('?');
break;
}
}
}
static uint16_t button_statemachine(uint8_t event)
{
static uint8_t oldstate;
uint8_t state = oldstate;
uint16_t timer;
do {
if (state != oldstate) {
event = EV_STATE_ENTER;
}
switch (state) {
case STATE_IDLE:
if (event == EV_STATE_ENTER) {
led_mode = LED_OFF;
timer = 0xFFFF; /* stop timer */
} else if (event == EV_BUTTON_PRESSED) {
state = STATE_PRESSED;
set_reset(0);
}
break;
case STATE_PRESSED:
if (event == EV_STATE_ENTER) {
led_mode = LED_ON;
timer = 5; /* timeout 50ms (== reset length) */
} else if (event == EV_BUTTON_RELEASED) {
state = STATE_IDLE;
set_reset(1);
} else if (event == EV_TIMEOUT) {
state = STATE_PRESSED2;
set_reset(1);
}
break;
case STATE_PRESSED2:
if (event == EV_STATE_ENTER) {
led_mode = LED_OFF;
timer = 500; /* timeout in 5s */
} else if (event == EV_BUTTON_RELEASED) {
state = STATE_IDLE;
} else if (event == EV_TIMEOUT) {
switch (SPCR) {
case SPI_MODE1:
state = STATE_SPEED1;
break;
case SPI_MODE2:
state = STATE_SPEED2;
break;
case SPI_MODE3:
state = STATE_SPEED3;
break;
default:
case SPI_MODE4:
state = STATE_SPEED4;
break;
}
}
break;
case STATE_SPEED1:
if (event == EV_STATE_ENTER) {
led_mode = LED_SPEED1;
timer = 500; /* timeout in 5s */
} else if (event == EV_BUTTON_PRESSED) {
state = STATE_SPEED2;
} else if (event == EV_TIMEOUT) {
state = STATE_NVRAM_STORE;
SPCR = SPI_MODE1;
}
break;
case STATE_SPEED2:
if (event == EV_STATE_ENTER) {
led_mode = LED_SPEED2;
timer = 500; /* timeout in 5s */
} else if (event == EV_BUTTON_PRESSED) {
state = STATE_SPEED3;
} else if (event == EV_TIMEOUT) {
state = STATE_NVRAM_STORE;
SPCR = SPI_MODE2;
}
break;
case STATE_SPEED3:
if (event == EV_STATE_ENTER) {
led_mode = LED_SPEED3;
timer = 500; /* timeout in 5s */
} else if (event == EV_BUTTON_PRESSED) {
state = STATE_SPEED4;
} else if (event == EV_TIMEOUT) {
state = STATE_NVRAM_STORE;
SPCR = SPI_MODE3;
}
break;
case STATE_SPEED4:
if (event == EV_STATE_ENTER) {
led_mode = LED_SPEED4;
timer = 500; /* timeout in 5s */
} else if (event == EV_BUTTON_PRESSED) {
state = STATE_SPEED1;
} else if (event == EV_TIMEOUT) {
state = STATE_NVRAM_STORE;
SPCR = SPI_MODE4;
}
break;
default:
state = STATE_IDLE;
break;
}
if (state == STATE_NVRAM_STORE) {
state = STATE_IDLE;
nvram_data.spi_mode = SPCR;
nvram_start_write();
}
if (event == EV_STATE_ENTER) {
oldstate = state;
}
} while (state != oldstate);
return timer;
}
/* time keeping */
ISR(TIMER0_OVF_vect)
{
uint8_t event = EV_NONE;
/* restart timer */
TCNT0 = TIMER_RELOAD;
static uint8_t prev_pressed;
if (PIND & (1<<RESET_IN)) {
if (!prev_pressed) {
event = EV_BUTTON_PRESSED;
prev_pressed = 1;
}
} else {
if (prev_pressed) {
event = EV_BUTTON_RELEASED;
prev_pressed = 0;
}
}
static uint16_t timer;
if (timer) {
timer--;
if (timer == 0) {
event = EV_TIMEOUT;
}
}
if (event != EV_NONE) {
uint16_t new_timer = button_statemachine(event);
if (new_timer == 0xFFFF) {
timer = 0;
} else if (new_timer > 0) {
timer = new_timer;
}
}
/* update LED */
static uint8_t led_timer;
if (led_mode & ((led_timer++ & 0xFF) | 0x80)) {
PORTB &= ~(1<<ISP_LED);
} else {
PORTB |= (1<<ISP_LED);
}
}
int main(void) __attribute__ ((noreturn));
int main(void)
{
/* ISP_RESET and ISP_LED are outputs, pullup SlaveSelect */
PORTB = (1<<ISP_RESET) | (1<<ISP_LED) | (1<<PORTB4);
DDRB = (1<<ISP_RESET) | (1<<ISP_LED);
/* Set baud rate */
UBRRH = (UART_CALC_BAUDRATE(BAUDRATE)>>8) & 0xFF;
UBRRL = (UART_CALC_BAUDRATE(BAUDRATE) & 0xFF);
/* enable usart with 8n1 */
UCSRB = (1<<TXEN) | (1<<RXEN);
UCSRC = (1<<URSEL) | (1<<UCSZ1) | (1<<UCSZ0);
/* read stored parameters */
nvram_read();
/* enable SPI master mode */
SPCR = nvram_data.spi_mode;
/* timer0, FCPU/1024, overflow interrupt */
TCCR0 = (1<<CS02) | (1<<CS00);
TIMSK = (1<<TOIE0);
sei();
cmdloop();
}