|
|
@ -14,9 +14,45 @@ |
|
|
|
|
|
|
|
#ifdef USE_SERIAL |
|
|
|
|
|
|
|
// Serial pulse period in microseconds. Its probably a bad idea to lower this |
|
|
|
// value. |
|
|
|
#define SERIAL_DELAY 30 |
|
|
|
#define _delay_sub_us(x) __builtin_avr_delay_cycles(x) |
|
|
|
|
|
|
|
// Serial pulse period in microseconds. |
|
|
|
#define SELECT_SERIAL_SPEED 1 |
|
|
|
#if SELECT_SERIAL_SPEED == 0 |
|
|
|
// Very High speed |
|
|
|
#define SERIAL_DELAY 4 // micro sec |
|
|
|
#define READ_WRITE_START_ADJUST 30 // cycles |
|
|
|
#define READ_WRITE_WIDTH_ADJUST 10 // cycles |
|
|
|
#elif SELECT_SERIAL_SPEED == 1 |
|
|
|
// High speed |
|
|
|
#define SERIAL_DELAY 6 // micro sec |
|
|
|
#define READ_WRITE_START_ADJUST 23 // cycles |
|
|
|
#define READ_WRITE_WIDTH_ADJUST 10 // cycles |
|
|
|
#elif SELECT_SERIAL_SPEED == 2 |
|
|
|
// Middle speed |
|
|
|
#define SERIAL_DELAY 12 // micro sec |
|
|
|
#define READ_WRITE_START_ADJUST 25 // cycles |
|
|
|
#define READ_WRITE_WIDTH_ADJUST 10 // cycles |
|
|
|
#elif SELECT_SERIAL_SPEED == 3 |
|
|
|
// Low speed |
|
|
|
#define SERIAL_DELAY 24 // micro sec |
|
|
|
#define READ_WRITE_START_ADJUST 25 // cycles |
|
|
|
#define READ_WRITE_WIDTH_ADJUST 10 // cycles |
|
|
|
#elif SELECT_SERIAL_SPEED == 4 |
|
|
|
// Very Low speed |
|
|
|
#define SERIAL_DELAY 50 // micro sec |
|
|
|
#define READ_WRITE_START_ADJUST 25 // cycles |
|
|
|
#define READ_WRITE_WIDTH_ADJUST 10 // cycles |
|
|
|
#else |
|
|
|
#error Illegal Serial Speed |
|
|
|
#endif |
|
|
|
|
|
|
|
|
|
|
|
#define SERIAL_DELAY_HALF1 (SERIAL_DELAY/2) |
|
|
|
#define SERIAL_DELAY_HALF2 (SERIAL_DELAY - SERIAL_DELAY/2) |
|
|
|
|
|
|
|
#define SLAVE_INT_WIDTH 1 |
|
|
|
#define SLAVE_INT_RESPONSE_TIME SERIAL_DELAY |
|
|
|
|
|
|
|
uint8_t volatile serial_slave_buffer[SERIAL_SLAVE_BUFFER_LENGTH] = {0}; |
|
|
|
uint8_t volatile serial_master_buffer[SERIAL_MASTER_BUFFER_LENGTH] = {0}; |
|
|
@ -28,9 +64,17 @@ inline static |
|
|
|
void serial_delay(void) { |
|
|
|
_delay_us(SERIAL_DELAY); |
|
|
|
} |
|
|
|
void serial_delay_short(void) { |
|
|
|
_delay_us(SERIAL_DELAY-1); |
|
|
|
|
|
|
|
inline static |
|
|
|
void serial_delay_half1(void) { |
|
|
|
_delay_us(SERIAL_DELAY_HALF1); |
|
|
|
} |
|
|
|
|
|
|
|
inline static |
|
|
|
void serial_delay_half2(void) { |
|
|
|
_delay_us(SERIAL_DELAY_HALF2); |
|
|
|
} |
|
|
|
|
|
|
|
inline static |
|
|
|
void serial_output(void) { |
|
|
|
SERIAL_PIN_DDR |= SERIAL_PIN_MASK; |
|
|
@ -38,7 +82,7 @@ void serial_output(void) { |
|
|
|
|
|
|
|
// make the serial pin an input with pull-up resistor |
|
|
|
inline static |
|
|
|
void serial_input(void) { |
|
|
|
void serial_input_with_pullup(void) { |
|
|
|
SERIAL_PIN_DDR &= ~SERIAL_PIN_MASK; |
|
|
|
SERIAL_PIN_PORT |= SERIAL_PIN_MASK; |
|
|
|
} |
|
|
@ -64,7 +108,7 @@ void serial_master_init(void) { |
|
|
|
} |
|
|
|
|
|
|
|
void serial_slave_init(void) { |
|
|
|
serial_input(); |
|
|
|
serial_input_with_pullup(); |
|
|
|
|
|
|
|
#ifndef USE_SERIAL_PD2 |
|
|
|
// Enable INT0 |
|
|
@ -79,25 +123,21 @@ void serial_slave_init(void) { |
|
|
|
#endif |
|
|
|
} |
|
|
|
|
|
|
|
// Used by the master to synchronize timing with the slave. |
|
|
|
// Used by the sender to synchronize timing with the reciver. |
|
|
|
static |
|
|
|
void sync_recv(void) { |
|
|
|
serial_input(); |
|
|
|
for (int i = 0; i < SERIAL_DELAY*5 && serial_read_pin(); i++ ) { |
|
|
|
} |
|
|
|
// This shouldn't hang if the slave disconnects because the |
|
|
|
// serial line will float to high if the slave does disconnect. |
|
|
|
while (!serial_read_pin()); |
|
|
|
//serial_delay(); |
|
|
|
_delay_us(SERIAL_DELAY-5); |
|
|
|
} |
|
|
|
|
|
|
|
// Used by the slave to send a synchronization signal to the master. |
|
|
|
// Used by the reciver to send a synchronization signal to the sender. |
|
|
|
static |
|
|
|
void sync_send(void) { |
|
|
|
serial_output(); |
|
|
|
|
|
|
|
serial_low(); |
|
|
|
serial_delay(); |
|
|
|
|
|
|
|
serial_high(); |
|
|
|
} |
|
|
|
|
|
|
@ -105,66 +145,70 @@ void sync_send(void) { |
|
|
|
static |
|
|
|
uint8_t serial_read_byte(void) { |
|
|
|
uint8_t byte = 0; |
|
|
|
serial_input(); |
|
|
|
_delay_sub_us(READ_WRITE_START_ADJUST); |
|
|
|
for ( uint8_t i = 0; i < 8; ++i) { |
|
|
|
serial_delay_half1(); // read the middle of pulses |
|
|
|
byte = (byte << 1) | serial_read_pin(); |
|
|
|
serial_delay(); |
|
|
|
_delay_us(1); |
|
|
|
_delay_sub_us(READ_WRITE_WIDTH_ADJUST); |
|
|
|
serial_delay_half2(); |
|
|
|
} |
|
|
|
|
|
|
|
return byte; |
|
|
|
} |
|
|
|
|
|
|
|
// Sends a byte with MSB ordering |
|
|
|
static |
|
|
|
void serial_write_byte(uint8_t data) { |
|
|
|
uint8_t b = 8; |
|
|
|
serial_output(); |
|
|
|
while( b-- ) { |
|
|
|
if(data & (1 << b)) { |
|
|
|
uint8_t b = 1<<7; |
|
|
|
while( b ) { |
|
|
|
if(data & b) { |
|
|
|
serial_high(); |
|
|
|
} else { |
|
|
|
serial_low(); |
|
|
|
} |
|
|
|
b >>= 1; |
|
|
|
serial_delay(); |
|
|
|
} |
|
|
|
serial_low(); // sync_send() / senc_recv() need raise edge |
|
|
|
} |
|
|
|
|
|
|
|
// interrupt handle to be used by the slave device |
|
|
|
ISR(SERIAL_PIN_INTERRUPT) { |
|
|
|
sync_send(); |
|
|
|
serial_output(); |
|
|
|
|
|
|
|
// slave send phase |
|
|
|
uint8_t checksum = 0; |
|
|
|
for (int i = 0; i < SERIAL_SLAVE_BUFFER_LENGTH; ++i) { |
|
|
|
serial_write_byte(serial_slave_buffer[i]); |
|
|
|
sync_send(); |
|
|
|
serial_write_byte(serial_slave_buffer[i]); |
|
|
|
checksum += serial_slave_buffer[i]; |
|
|
|
} |
|
|
|
serial_write_byte(checksum); |
|
|
|
sync_send(); |
|
|
|
serial_write_byte(checksum); |
|
|
|
|
|
|
|
// wait for the sync to finish sending |
|
|
|
serial_delay(); |
|
|
|
|
|
|
|
// read the middle of pulses |
|
|
|
_delay_us(SERIAL_DELAY/2); |
|
|
|
// slave switch to input |
|
|
|
sync_send(); //0 |
|
|
|
serial_delay_half1(); //1 |
|
|
|
serial_low(); //2 |
|
|
|
serial_input_with_pullup(); //2 |
|
|
|
serial_delay_half1(); //3 |
|
|
|
|
|
|
|
// slave recive phase |
|
|
|
uint8_t checksum_computed = 0; |
|
|
|
for (int i = 0; i < SERIAL_MASTER_BUFFER_LENGTH; ++i) { |
|
|
|
sync_recv(); |
|
|
|
serial_master_buffer[i] = serial_read_byte(); |
|
|
|
sync_send(); |
|
|
|
checksum_computed += serial_master_buffer[i]; |
|
|
|
} |
|
|
|
sync_recv(); |
|
|
|
uint8_t checksum_received = serial_read_byte(); |
|
|
|
sync_send(); |
|
|
|
|
|
|
|
serial_input(); // end transaction |
|
|
|
|
|
|
|
if ( checksum_computed != checksum_received ) { |
|
|
|
status |= SLAVE_DATA_CORRUPT; |
|
|
|
} else { |
|
|
|
status &= ~SLAVE_DATA_CORRUPT; |
|
|
|
} |
|
|
|
|
|
|
|
sync_recv(); //weit master output to high |
|
|
|
} |
|
|
|
|
|
|
|
inline |
|
|
@ -178,6 +222,7 @@ bool serial_slave_DATA_CORRUPT(void) { |
|
|
|
// Returns: |
|
|
|
// 0 => no error |
|
|
|
// 1 => slave did not respond |
|
|
|
// 2 => checksum error |
|
|
|
int serial_update_buffers(void) { |
|
|
|
// this code is very time dependent, so we need to disable interrupts |
|
|
|
cli(); |
|
|
@ -185,51 +230,61 @@ int serial_update_buffers(void) { |
|
|
|
// signal to the slave that we want to start a transaction |
|
|
|
serial_output(); |
|
|
|
serial_low(); |
|
|
|
_delay_us(1); |
|
|
|
_delay_us(SLAVE_INT_WIDTH); |
|
|
|
|
|
|
|
// wait for the slaves response |
|
|
|
serial_input(); |
|
|
|
serial_high(); |
|
|
|
_delay_us(SERIAL_DELAY); |
|
|
|
serial_input_with_pullup(); |
|
|
|
_delay_us(SLAVE_INT_RESPONSE_TIME); |
|
|
|
|
|
|
|
// check if the slave is present |
|
|
|
if (serial_read_pin()) { |
|
|
|
// slave failed to pull the line low, assume not present |
|
|
|
serial_output(); |
|
|
|
serial_high(); |
|
|
|
sei(); |
|
|
|
return 1; |
|
|
|
} |
|
|
|
|
|
|
|
// master recive phase |
|
|
|
// if the slave is present syncronize with it |
|
|
|
sync_recv(); |
|
|
|
|
|
|
|
uint8_t checksum_computed = 0; |
|
|
|
// receive data from the slave |
|
|
|
for (int i = 0; i < SERIAL_SLAVE_BUFFER_LENGTH; ++i) { |
|
|
|
serial_slave_buffer[i] = serial_read_byte(); |
|
|
|
sync_recv(); |
|
|
|
serial_slave_buffer[i] = serial_read_byte(); |
|
|
|
checksum_computed += serial_slave_buffer[i]; |
|
|
|
} |
|
|
|
uint8_t checksum_received = serial_read_byte(); |
|
|
|
sync_recv(); |
|
|
|
uint8_t checksum_received = serial_read_byte(); |
|
|
|
|
|
|
|
if (checksum_computed != checksum_received) { |
|
|
|
serial_output(); |
|
|
|
serial_high(); |
|
|
|
sei(); |
|
|
|
return 2; |
|
|
|
} |
|
|
|
|
|
|
|
// master switch to output |
|
|
|
sync_recv(); //0 |
|
|
|
serial_delay(); //1 |
|
|
|
serial_low(); //3 |
|
|
|
serial_output(); // 3 |
|
|
|
serial_delay_half1(); //4 |
|
|
|
|
|
|
|
// master send phase |
|
|
|
uint8_t checksum = 0; |
|
|
|
// send data to the slave |
|
|
|
|
|
|
|
for (int i = 0; i < SERIAL_MASTER_BUFFER_LENGTH; ++i) { |
|
|
|
sync_send(); |
|
|
|
serial_write_byte(serial_master_buffer[i]); |
|
|
|
sync_recv(); |
|
|
|
checksum += serial_master_buffer[i]; |
|
|
|
} |
|
|
|
sync_send(); |
|
|
|
serial_write_byte(checksum); |
|
|
|
sync_recv(); |
|
|
|
|
|
|
|
// always, release the line when not in use |
|
|
|
serial_output(); |
|
|
|
serial_high(); |
|
|
|
sync_send(); |
|
|
|
|
|
|
|
sei(); |
|
|
|
return 0; |
|
|
|