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Split TWI handling into read/write functions

master
Olaf Rempel 1 month ago
parent
commit
eee017dedf
2 changed files with 143 additions and 130 deletions
  1. +4
    -4
      README.md
  2. +139
    -126
      main.c

+ 4
- 4
README.md View File

@@ -10,10 +10,10 @@ Currently the following AVR MCUs are supported:

AVR MCU | Flash bytes used (.text + .data) | Bootloader region size
--- | --- | ---
atmega8 | 900 (0x384) | 512 words
atmega88 | 950 (0x3B6) | 512 words
atmega168 | 1002 (0x3EA) | 512 words
atmega328p | 1002 (0x3EA) | 512 words
atmega8 | 868 (0x364) | 512 words
atmega88 | 920 (0x398) | 512 words
atmega168 | 972 (0x3CC) | 512 words
atmega328p | 972 (0x3CC) | 512 words
(Compiled on Ubuntu 18.04 LTS (gcc 5.4.0 / avr-libc 2.0.0) with EEPROM and LED support)



+ 139
- 126
main.c View File

@@ -210,135 +210,175 @@ static void write_eeprom_byte(uint8_t val)


/* *************************************************************************
* TWI_vect
* TWI_data_write
* ************************************************************************* */
ISR(TWI_vect)
static uint8_t TWI_data_write(uint8_t bcnt, uint8_t data)
{
static uint8_t bcnt;
uint8_t data;
uint8_t ack = (1<<TWEA);
uint8_t ack = 0x01;

switch (TWSR & 0xF8)
switch (bcnt)
{
/* SLA+W received, ACK returned -> receive data and ACK */
case 0x60:
bcnt = 0;
LED_RT_ON();
TWCR |= (1<<TWINT) | (1<<TWEA);
break;
case 0:
switch (data)
{
case CMD_SWITCH_APPLICATION:
case CMD_WRITE_MEMORY:
/* no break */

/* prev. SLA+W, data received, ACK returned -> receive data and ACK */
case 0x80:
data = TWDR;
case CMD_WAIT:
/* abort countdown */
boot_timeout = 0;
break;

switch (bcnt)
default:
/* boot app now */
cmd = CMD_BOOT_APPLICATION;
ack = 0x00;
break;
}

cmd = data;
break;

case 1:
switch (cmd)
{
case 0:
switch (data)
case CMD_SWITCH_APPLICATION:
if (data == BOOTTYPE_APPLICATION)
{
case CMD_SWITCH_APPLICATION:
case CMD_WRITE_MEMORY:
bcnt++;
/* no break */

case CMD_WAIT:
/* abort countdown */
boot_timeout = 0;
break;

default:
/* boot app now */
cmd = CMD_BOOT_APPLICATION;
ack = (0<<TWEA);
break;
cmd = CMD_BOOT_APPLICATION;
}

cmd = data;
ack = 0x00;
break;

case 1:
switch (cmd)
case CMD_WRITE_MEMORY:
if (data == MEMTYPE_CHIPINFO)
{
cmd = CMD_WRITE_CHIPINFO;
}
else if (data == MEMTYPE_FLASH)
{
case CMD_SWITCH_APPLICATION:
if (data == BOOTTYPE_APPLICATION)
{
cmd = CMD_BOOT_APPLICATION;
}

ack = (0<<TWEA);
break;

case CMD_WRITE_MEMORY:
bcnt++;
if (data == MEMTYPE_CHIPINFO)
{
cmd = CMD_WRITE_CHIPINFO;
}
else if (data == MEMTYPE_FLASH)
{
cmd = CMD_WRITE_FLASH;
}
cmd = CMD_WRITE_FLASH;
}
#if (EEPROM_SUPPORT)
else if (data == MEMTYPE_EEPROM)
{
cmd = CMD_WRITE_EEPROM;
}
else if (data == MEMTYPE_EEPROM)
{
cmd = CMD_WRITE_EEPROM;
}
#endif /* (EEPROM_SUPPORT) */
else
{
ack = (0<<TWEA);
}
break;

default:
ack = (0<<TWEA);
break;
else
{
ack = 0x00;
}
break;

case 2:
case 3:
addr <<= 8;
addr |= data;
bcnt++;
default:
ack = 0x00;
break;
}
break;

default:
switch (cmd)
case 2:
case 3:
addr <<= 8;
addr |= data;
break;

default:
switch (cmd)
{
case CMD_WRITE_FLASH:
buf[bcnt -4] = data;
if (bcnt >= sizeof(buf) +3)
{
case CMD_WRITE_FLASH:
buf[bcnt -4] = data;
if (bcnt < sizeof(buf) +3)
{
bcnt++;
}
else
{
write_flash_page();
ack = (0<<TWEA);
}
break;
write_flash_page();
ack = 0x00;
}
break;

#if (EEPROM_SUPPORT)
case CMD_WRITE_EEPROM:
write_eeprom_byte(data);
bcnt++;
break;
case CMD_WRITE_EEPROM:
write_eeprom_byte(data);
break;
#endif /* (EEPROM_SUPPORT) */

default:
ack = (0<<TWEA);
break;
}
default:
ack = 0x00;
break;
}
break;
}

if (ack == 0x00)
return ack;
} /* TWI_data_write */


/* *************************************************************************
* TWI_data_read
* ************************************************************************* */
static uint8_t TWI_data_read(uint8_t bcnt)
{
uint8_t data;

switch (cmd)
{
case CMD_READ_VERSION:
bcnt %= sizeof(info);
data = info[bcnt];
break;

case CMD_READ_CHIPINFO:
bcnt %= sizeof(chipinfo);
data = chipinfo[bcnt];
break;

case CMD_READ_FLASH:
data = pgm_read_byte_near(addr++);
break;

#if (EEPROM_SUPPORT)
case CMD_READ_EEPROM:
data = read_eeprom_byte();
break;
#endif /* (EEPROM_SUPPORT) */

default:
data = 0xFF;
break;
}

return data;
} /* TWI_data_read */


/* *************************************************************************
* TWI_vect
* ************************************************************************* */
ISR(TWI_vect)
{
static uint8_t bcnt;

switch (TWSR & 0xF8)
{
/* SLA+W received, ACK returned -> receive data and ACK */
case 0x60:
bcnt = 0;
LED_RT_ON();
TWCR |= (1<<TWINT) | (1<<TWEA);
break;

/* prev. SLA+W, data received, ACK returned -> receive data and ACK */
case 0x80:
if (TWI_data_write(bcnt++, TWDR))
{
TWCR |= (1<<TWINT) | (1<<TWEA);
}
else
{
TWCR |= (1<<TWINT);
bcnt = 0;
}

TWCR |= (1<<TWINT) | ack;
break;

/* SLA+R received, ACK returned -> send data */
@@ -348,34 +388,7 @@ ISR(TWI_vect)

/* prev. SLA+R, data sent, ACK returned -> send data */
case 0xB8:
switch (cmd)
{
case CMD_READ_VERSION:
data = info[bcnt++];
bcnt %= sizeof(info);
break;

case CMD_READ_CHIPINFO:
data = chipinfo[bcnt++];
bcnt %= sizeof(chipinfo);
break;

case CMD_READ_FLASH:
data = pgm_read_byte_near(addr++);
break;

#if (EEPROM_SUPPORT)
case CMD_READ_EEPROM:
data = read_eeprom_byte();
break;
#endif /* (EEPROM_SUPPORT) */

default:
data = 0xFF;
break;
}

TWDR = data;
TWDR = TWI_data_read(bcnt++);
TWCR |= (1<<TWINT) | (1<<TWEA);
break;


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