diff options
Diffstat (limited to 'keyboards/redox/serial.c')
| -rw-r--r-- | keyboards/redox/serial.c | 228 |
1 files changed, 0 insertions, 228 deletions
diff --git a/keyboards/redox/serial.c b/keyboards/redox/serial.c deleted file mode 100644 index 6faed09ce..000000000 --- a/keyboards/redox/serial.c +++ /dev/null | |||
| @@ -1,228 +0,0 @@ | |||
| 1 | /* | ||
| 2 | * WARNING: be careful changing this code, it is very timing dependent | ||
| 3 | */ | ||
| 4 | |||
| 5 | #ifndef F_CPU | ||
| 6 | #define F_CPU 16000000 | ||
| 7 | #endif | ||
| 8 | |||
| 9 | #include <avr/io.h> | ||
| 10 | #include <avr/interrupt.h> | ||
| 11 | #include <util/delay.h> | ||
| 12 | #include <stdbool.h> | ||
| 13 | #include "serial.h" | ||
| 14 | |||
| 15 | #ifdef USE_SERIAL | ||
| 16 | |||
| 17 | // Serial pulse period in microseconds. Its probably a bad idea to lower this | ||
| 18 | // value. | ||
| 19 | #define SERIAL_DELAY 24 | ||
| 20 | |||
| 21 | uint8_t volatile serial_slave_buffer[SERIAL_SLAVE_BUFFER_LENGTH] = {0}; | ||
| 22 | uint8_t volatile serial_master_buffer[SERIAL_MASTER_BUFFER_LENGTH] = {0}; | ||
| 23 | |||
| 24 | #define SLAVE_DATA_CORRUPT (1<<0) | ||
| 25 | volatile uint8_t status = 0; | ||
| 26 | |||
| 27 | inline static | ||
| 28 | void serial_delay(void) { | ||
| 29 | _delay_us(SERIAL_DELAY); | ||
| 30 | } | ||
| 31 | |||
| 32 | inline static | ||
| 33 | void serial_output(void) { | ||
| 34 | SERIAL_PIN_DDR |= SERIAL_PIN_MASK; | ||
| 35 | } | ||
| 36 | |||
| 37 | // make the serial pin an input with pull-up resistor | ||
| 38 | inline static | ||
| 39 | void serial_input(void) { | ||
| 40 | SERIAL_PIN_DDR &= ~SERIAL_PIN_MASK; | ||
| 41 | SERIAL_PIN_PORT |= SERIAL_PIN_MASK; | ||
| 42 | } | ||
| 43 | |||
| 44 | inline static | ||
| 45 | uint8_t serial_read_pin(void) { | ||
| 46 | return !!(SERIAL_PIN_INPUT & SERIAL_PIN_MASK); | ||
| 47 | } | ||
| 48 | |||
| 49 | inline static | ||
| 50 | void serial_low(void) { | ||
| 51 | SERIAL_PIN_PORT &= ~SERIAL_PIN_MASK; | ||
| 52 | } | ||
| 53 | |||
| 54 | inline static | ||
| 55 | void serial_high(void) { | ||
| 56 | SERIAL_PIN_PORT |= SERIAL_PIN_MASK; | ||
| 57 | } | ||
| 58 | |||
| 59 | void serial_master_init(void) { | ||
| 60 | serial_output(); | ||
| 61 | serial_high(); | ||
| 62 | } | ||
| 63 | |||
| 64 | void serial_slave_init(void) { | ||
| 65 | serial_input(); | ||
| 66 | |||
| 67 | // Enable INT0 | ||
| 68 | EIMSK |= _BV(INT0); | ||
| 69 | // Trigger on falling edge of INT0 | ||
| 70 | EICRA &= ~(_BV(ISC00) | _BV(ISC01)); | ||
| 71 | } | ||
| 72 | |||
| 73 | // Used by the master to synchronize timing with the slave. | ||
| 74 | static | ||
| 75 | void sync_recv(void) { | ||
| 76 | serial_input(); | ||
| 77 | // This shouldn't hang if the slave disconnects because the | ||
| 78 | // serial line will float to high if the slave does disconnect. | ||
| 79 | while (!serial_read_pin()); | ||
| 80 | serial_delay(); | ||
| 81 | } | ||
| 82 | |||
| 83 | // Used by the slave to send a synchronization signal to the master. | ||
| 84 | static | ||
| 85 | void sync_send(void) { | ||
| 86 | serial_output(); | ||
| 87 | |||
| 88 | serial_low(); | ||
| 89 | serial_delay(); | ||
| 90 | |||
| 91 | serial_high(); | ||
| 92 | } | ||
| 93 | |||
| 94 | // Reads a byte from the serial line | ||
| 95 | static | ||
| 96 | uint8_t serial_read_byte(void) { | ||
| 97 | uint8_t byte = 0; | ||
| 98 | serial_input(); | ||
| 99 | for ( uint8_t i = 0; i < 8; ++i) { | ||
| 100 | byte = (byte << 1) | serial_read_pin(); | ||
| 101 | serial_delay(); | ||
| 102 | _delay_us(1); | ||
| 103 | } | ||
| 104 | |||
| 105 | return byte; | ||
| 106 | } | ||
| 107 | |||
| 108 | // Sends a byte with MSB ordering | ||
| 109 | static | ||
| 110 | void serial_write_byte(uint8_t data) { | ||
| 111 | uint8_t b = 8; | ||
| 112 | serial_output(); | ||
| 113 | while( b-- ) { | ||
| 114 | if(data & (1 << b)) { | ||
| 115 | serial_high(); | ||
| 116 | } else { | ||
| 117 | serial_low(); | ||
| 118 | } | ||
| 119 | serial_delay(); | ||
| 120 | } | ||
| 121 | } | ||
| 122 | |||
| 123 | // interrupt handle to be used by the slave device | ||
| 124 | ISR(SERIAL_PIN_INTERRUPT) { | ||
| 125 | sync_send(); | ||
| 126 | |||
| 127 | uint8_t checksum = 0; | ||
| 128 | for (int i = 0; i < SERIAL_SLAVE_BUFFER_LENGTH; ++i) { | ||
| 129 | serial_write_byte(serial_slave_buffer[i]); | ||
| 130 | sync_send(); | ||
| 131 | checksum += serial_slave_buffer[i]; | ||
| 132 | } | ||
| 133 | serial_write_byte(checksum); | ||
| 134 | sync_send(); | ||
| 135 | |||
| 136 | // wait for the sync to finish sending | ||
| 137 | serial_delay(); | ||
| 138 | |||
| 139 | // read the middle of pulses | ||
| 140 | _delay_us(SERIAL_DELAY/2); | ||
| 141 | |||
| 142 | uint8_t checksum_computed = 0; | ||
| 143 | for (int i = 0; i < SERIAL_MASTER_BUFFER_LENGTH; ++i) { | ||
| 144 | serial_master_buffer[i] = serial_read_byte(); | ||
| 145 | sync_send(); | ||
| 146 | checksum_computed += serial_master_buffer[i]; | ||
| 147 | } | ||
| 148 | uint8_t checksum_received = serial_read_byte(); | ||
| 149 | sync_send(); | ||
| 150 | |||
| 151 | serial_input(); // end transaction | ||
| 152 | |||
| 153 | if ( checksum_computed != checksum_received ) { | ||
| 154 | status |= SLAVE_DATA_CORRUPT; | ||
| 155 | } else { | ||
| 156 | status &= ~SLAVE_DATA_CORRUPT; | ||
| 157 | } | ||
| 158 | } | ||
| 159 | |||
| 160 | inline | ||
| 161 | bool serial_slave_DATA_CORRUPT(void) { | ||
| 162 | return status & SLAVE_DATA_CORRUPT; | ||
| 163 | } | ||
| 164 | |||
| 165 | // Copies the serial_slave_buffer to the master and sends the | ||
| 166 | // serial_master_buffer to the slave. | ||
| 167 | // | ||
| 168 | // Returns: | ||
| 169 | // 0 => no error | ||
| 170 | // 1 => slave did not respond | ||
| 171 | int serial_update_buffers(void) { | ||
| 172 | // this code is very time dependent, so we need to disable interrupts | ||
| 173 | cli(); | ||
| 174 | |||
| 175 | // signal to the slave that we want to start a transaction | ||
| 176 | serial_output(); | ||
| 177 | serial_low(); | ||
| 178 | _delay_us(1); | ||
| 179 | |||
| 180 | // wait for the slaves response | ||
| 181 | serial_input(); | ||
| 182 | serial_high(); | ||
| 183 | _delay_us(SERIAL_DELAY); | ||
| 184 | |||
| 185 | // check if the slave is present | ||
| 186 | if (serial_read_pin()) { | ||
| 187 | // slave failed to pull the line low, assume not present | ||
| 188 | sei(); | ||
| 189 | return 1; | ||
| 190 | } | ||
| 191 | |||
| 192 | // if the slave is present syncronize with it | ||
| 193 | sync_recv(); | ||
| 194 | |||
| 195 | uint8_t checksum_computed = 0; | ||
| 196 | // receive data from the slave | ||
| 197 | for (int i = 0; i < SERIAL_SLAVE_BUFFER_LENGTH; ++i) { | ||
| 198 | serial_slave_buffer[i] = serial_read_byte(); | ||
| 199 | sync_recv(); | ||
| 200 | checksum_computed += serial_slave_buffer[i]; | ||
| 201 | } | ||
| 202 | uint8_t checksum_received = serial_read_byte(); | ||
| 203 | sync_recv(); | ||
| 204 | |||
| 205 | if (checksum_computed != checksum_received) { | ||
| 206 | sei(); | ||
| 207 | return 1; | ||
| 208 | } | ||
| 209 | |||
| 210 | uint8_t checksum = 0; | ||
| 211 | // send data to the slave | ||
| 212 | for (int i = 0; i < SERIAL_MASTER_BUFFER_LENGTH; ++i) { | ||
| 213 | serial_write_byte(serial_master_buffer[i]); | ||
| 214 | sync_recv(); | ||
| 215 | checksum += serial_master_buffer[i]; | ||
| 216 | } | ||
| 217 | serial_write_byte(checksum); | ||
| 218 | sync_recv(); | ||
| 219 | |||
| 220 | // always, release the line when not in use | ||
| 221 | serial_output(); | ||
| 222 | serial_high(); | ||
| 223 | |||
| 224 | sei(); | ||
| 225 | return 0; | ||
| 226 | } | ||
| 227 | |||
| 228 | #endif | ||
