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Diffstat (limited to 'keyboards/mint60/serial.c')
-rw-r--r-- | keyboards/mint60/serial.c | 295 |
1 files changed, 0 insertions, 295 deletions
diff --git a/keyboards/mint60/serial.c b/keyboards/mint60/serial.c deleted file mode 100644 index 5919415877..0000000000 --- a/keyboards/mint60/serial.c +++ /dev/null @@ -1,295 +0,0 @@ -/* - * WARNING: be careful changing this code, it is very timing dependent - */ - -#ifndef F_CPU -#define F_CPU 16000000 -#endif - -#include <avr/io.h> -#include <avr/interrupt.h> -#include <util/delay.h> -#include <stdbool.h> -#include "serial.h" - -#ifdef USE_SERIAL - -#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}; - -#define SLAVE_DATA_CORRUPT (1<<0) -volatile uint8_t status = 0; - -inline static -void serial_delay(void) { - _delay_us(SERIAL_DELAY); -} - -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; -} - -// make the serial pin an input with pull-up resistor -inline static -void serial_input_with_pullup(void) { - SERIAL_PIN_DDR &= ~SERIAL_PIN_MASK; - SERIAL_PIN_PORT |= SERIAL_PIN_MASK; -} - -inline static -uint8_t serial_read_pin(void) { - return !!(SERIAL_PIN_INPUT & SERIAL_PIN_MASK); -} - -inline static -void serial_low(void) { - SERIAL_PIN_PORT &= ~SERIAL_PIN_MASK; -} - -inline static -void serial_high(void) { - SERIAL_PIN_PORT |= SERIAL_PIN_MASK; -} - -void serial_master_init(void) { - serial_output(); - serial_high(); -} - -void serial_slave_init(void) { - serial_input_with_pullup(); - -#if SERIAL_PIN_MASK == _BV(PD0) - // Enable INT0 - EIMSK |= _BV(INT0); - // Trigger on falling edge of INT0 - EICRA &= ~(_BV(ISC00) | _BV(ISC01)); -#elif SERIAL_PIN_MASK == _BV(PD2) - // Enable INT2 - EIMSK |= _BV(INT2); - // Trigger on falling edge of INT2 - EICRA &= ~(_BV(ISC20) | _BV(ISC21)); -#else - #error unknown SERIAL_PIN_MASK value -#endif -} - -// Used by the sender to synchronize timing with the reciver. -static -void sync_recv(void) { - 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()); -} - -// Used by the reciver to send a synchronization signal to the sender. -static -void sync_send(void) { - serial_low(); - serial_delay(); - serial_high(); -} - -// Reads a byte from the serial line -static -uint8_t serial_read_byte(void) { - uint8_t byte = 0; - _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(); - _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 = 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) { - serial_output(); - - // slave send phase - uint8_t checksum = 0; - for (int i = 0; i < SERIAL_SLAVE_BUFFER_LENGTH; ++i) { - sync_send(); - serial_write_byte(serial_slave_buffer[i]); - checksum += serial_slave_buffer[i]; - } - sync_send(); - serial_write_byte(checksum); - - // 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(); - checksum_computed += serial_master_buffer[i]; - } - sync_recv(); - uint8_t checksum_received = serial_read_byte(); - - if ( checksum_computed != checksum_received ) { - status |= SLAVE_DATA_CORRUPT; - } else { - status &= ~SLAVE_DATA_CORRUPT; - } - - sync_recv(); //weit master output to high -} - -inline -bool serial_slave_DATA_CORRUPT(void) { - return status & SLAVE_DATA_CORRUPT; -} - -// Copies the serial_slave_buffer to the master and sends the -// serial_master_buffer to the slave. -// -// 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(); - - // signal to the slave that we want to start a transaction - serial_output(); - serial_low(); - _delay_us(SLAVE_INT_WIDTH); - - // wait for the slaves response - 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 - - uint8_t checksum_computed = 0; - // receive data from the slave - for (int i = 0; i < SERIAL_SLAVE_BUFFER_LENGTH; ++i) { - sync_recv(); - serial_slave_buffer[i] = serial_read_byte(); - checksum_computed += serial_slave_buffer[i]; - } - 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; - - for (int i = 0; i < SERIAL_MASTER_BUFFER_LENGTH; ++i) { - sync_send(); - serial_write_byte(serial_master_buffer[i]); - checksum += serial_master_buffer[i]; - } - sync_send(); - serial_write_byte(checksum); - - // always, release the line when not in use - sync_send(); - - sei(); - return 0; -} - -#endif |