-/*\r
- * WARNING: be careful changing this code, it is very timing dependent\r
- */\r
-\r
-#ifndef F_CPU\r
-#define F_CPU 16000000\r
-#endif\r
-\r
-#include <avr/io.h>\r
-#include <avr/interrupt.h>\r
-#include <util/delay.h>\r
-#include <stdbool.h>\r
-#include "serial.h"\r
-\r
-#ifdef USE_SERIAL\r
-\r
-// Serial pulse period in microseconds. Its probably a bad idea to lower this\r
-// value.\r
-#define SERIAL_DELAY 24\r
-\r
-uint8_t volatile serial_slave_buffer[SERIAL_SLAVE_BUFFER_LENGTH] = {0};\r
-uint8_t volatile serial_master_buffer[SERIAL_MASTER_BUFFER_LENGTH] = {0};\r
-\r
-#define SLAVE_DATA_CORRUPT (1<<0)\r
-volatile uint8_t status = 0;\r
-\r
-inline static\r
-void serial_delay(void) {\r
- _delay_us(SERIAL_DELAY);\r
-}\r
-\r
-inline static\r
-void serial_output(void) {\r
- SERIAL_PIN_DDR |= SERIAL_PIN_MASK;\r
-}\r
-\r
-// make the serial pin an input with pull-up resistor\r
-inline static\r
-void serial_input(void) {\r
- SERIAL_PIN_DDR &= ~SERIAL_PIN_MASK;\r
- SERIAL_PIN_PORT |= SERIAL_PIN_MASK;\r
-}\r
-\r
-inline static\r
-uint8_t serial_read_pin(void) {\r
- return !!(SERIAL_PIN_INPUT & SERIAL_PIN_MASK);\r
-}\r
-\r
-inline static\r
-void serial_low(void) {\r
- SERIAL_PIN_PORT &= ~SERIAL_PIN_MASK;\r
-}\r
-\r
-inline static\r
-void serial_high(void) {\r
- SERIAL_PIN_PORT |= SERIAL_PIN_MASK;\r
-}\r
-\r
-void serial_master_init(void) {\r
- serial_output();\r
- serial_high();\r
-}\r
-\r
-void serial_slave_init(void) {\r
- serial_input();\r
-\r
- // Enable INT0\r
- EIMSK |= _BV(INT0);\r
- // Trigger on falling edge of INT0\r
- EICRA &= ~(_BV(ISC00) | _BV(ISC01));\r
-}\r
-\r
-// Used by the master to synchronize timing with the slave.\r
-static\r
-void sync_recv(void) {\r
- serial_input();\r
- // This shouldn't hang if the slave disconnects because the\r
- // serial line will float to high if the slave does disconnect.\r
- while (!serial_read_pin());\r
- serial_delay();\r
-}\r
-\r
-// Used by the slave to send a synchronization signal to the master.\r
-static\r
-void sync_send(void) {\r
- serial_output();\r
-\r
- serial_low();\r
- serial_delay();\r
-\r
- serial_high();\r
-}\r
-\r
-// Reads a byte from the serial line\r
-static\r
-uint8_t serial_read_byte(void) {\r
- uint8_t byte = 0;\r
- serial_input();\r
- for ( uint8_t i = 0; i < 8; ++i) {\r
- byte = (byte << 1) | serial_read_pin();\r
- serial_delay();\r
- _delay_us(1);\r
- }\r
-\r
- return byte;\r
-}\r
-\r
-// Sends a byte with MSB ordering\r
-static\r
-void serial_write_byte(uint8_t data) {\r
- uint8_t b = 8;\r
- serial_output();\r
- while( b-- ) {\r
- if(data & (1 << b)) {\r
- serial_high();\r
- } else {\r
- serial_low();\r
- }\r
- serial_delay();\r
- }\r
-}\r
-\r
-// interrupt handle to be used by the slave device\r
-ISR(SERIAL_PIN_INTERRUPT) {\r
- sync_send();\r
-\r
- uint8_t checksum = 0;\r
- for (int i = 0; i < SERIAL_SLAVE_BUFFER_LENGTH; ++i) {\r
- serial_write_byte(serial_slave_buffer[i]);\r
- sync_send();\r
- checksum += serial_slave_buffer[i];\r
- }\r
- serial_write_byte(checksum);\r
- sync_send();\r
-\r
- // wait for the sync to finish sending\r
- serial_delay();\r
-\r
- // read the middle of pulses\r
- _delay_us(SERIAL_DELAY/2);\r
-\r
- uint8_t checksum_computed = 0;\r
- for (int i = 0; i < SERIAL_MASTER_BUFFER_LENGTH; ++i) {\r
- serial_master_buffer[i] = serial_read_byte();\r
- sync_send();\r
- checksum_computed += serial_master_buffer[i];\r
- }\r
- uint8_t checksum_received = serial_read_byte();\r
- sync_send();\r
-\r
- serial_input(); // end transaction\r
-\r
- if ( checksum_computed != checksum_received ) {\r
- status |= SLAVE_DATA_CORRUPT;\r
- } else {\r
- status &= ~SLAVE_DATA_CORRUPT;\r
- }\r
-}\r
-\r
-inline\r
-bool serial_slave_DATA_CORRUPT(void) {\r
- return status & SLAVE_DATA_CORRUPT;\r
-}\r
-\r
-// Copies the serial_slave_buffer to the master and sends the\r
-// serial_master_buffer to the slave.\r
-//\r
-// Returns:\r
-// 0 => no error\r
-// 1 => slave did not respond\r
-int serial_update_buffers(void) {\r
- // this code is very time dependent, so we need to disable interrupts\r
- cli();\r
-\r
- // signal to the slave that we want to start a transaction\r
- serial_output();\r
- serial_low();\r
- _delay_us(1);\r
-\r
- // wait for the slaves response\r
- serial_input();\r
- serial_high();\r
- _delay_us(SERIAL_DELAY);\r
-\r
- // check if the slave is present\r
- if (serial_read_pin()) {\r
- // slave failed to pull the line low, assume not present\r
- sei();\r
- return 1;\r
- }\r
-\r
- // if the slave is present syncronize with it\r
- sync_recv();\r
-\r
- uint8_t checksum_computed = 0;\r
- // receive data from the slave\r
- for (int i = 0; i < SERIAL_SLAVE_BUFFER_LENGTH; ++i) {\r
- serial_slave_buffer[i] = serial_read_byte();\r
- sync_recv();\r
- checksum_computed += serial_slave_buffer[i];\r
- }\r
- uint8_t checksum_received = serial_read_byte();\r
- sync_recv();\r
-\r
- if (checksum_computed != checksum_received) {\r
- sei();\r
- return 1;\r
- }\r
-\r
- uint8_t checksum = 0;\r
- // send data to the slave\r
- for (int i = 0; i < SERIAL_MASTER_BUFFER_LENGTH; ++i) {\r
- serial_write_byte(serial_master_buffer[i]);\r
- sync_recv();\r
- checksum += serial_master_buffer[i];\r
- }\r
- serial_write_byte(checksum);\r
- sync_recv();\r
-\r
- // always, release the line when not in use\r
- serial_output();\r
- serial_high();\r
-\r
- sei();\r
- return 0;\r
-}\r
-\r
-#endif\r
+/*
+ * 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
+
+// Serial pulse period in microseconds. Its probably a bad idea to lower this
+// value.
+#define SERIAL_DELAY 24
+
+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_output(void) {
+ SERIAL_PIN_DDR |= SERIAL_PIN_MASK;
+}
+
+// make the serial pin an input with pull-up resistor
+inline static
+void serial_input(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();
+
+ // Enable INT0
+ EIMSK |= _BV(INT0);
+ // Trigger on falling edge of INT0
+ EICRA &= ~(_BV(ISC00) | _BV(ISC01));
+}
+
+// Used by the master to synchronize timing with the slave.
+static
+void sync_recv(void) {
+ serial_input();
+ // 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();
+}
+
+// Used by the slave to send a synchronization signal to the master.
+static
+void sync_send(void) {
+ serial_output();
+
+ serial_low();
+ serial_delay();
+
+ serial_high();
+}
+
+// Reads a byte from the serial line
+static
+uint8_t serial_read_byte(void) {
+ uint8_t byte = 0;
+ serial_input();
+ for ( uint8_t i = 0; i < 8; ++i) {
+ byte = (byte << 1) | serial_read_pin();
+ serial_delay();
+ _delay_us(1);
+ }
+
+ 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)) {
+ serial_high();
+ } else {
+ serial_low();
+ }
+ serial_delay();
+ }
+}
+
+// interrupt handle to be used by the slave device
+ISR(SERIAL_PIN_INTERRUPT) {
+ sync_send();
+
+ uint8_t checksum = 0;
+ for (int i = 0; i < SERIAL_SLAVE_BUFFER_LENGTH; ++i) {
+ serial_write_byte(serial_slave_buffer[i]);
+ sync_send();
+ checksum += serial_slave_buffer[i];
+ }
+ serial_write_byte(checksum);
+ sync_send();
+
+ // wait for the sync to finish sending
+ serial_delay();
+
+ // read the middle of pulses
+ _delay_us(SERIAL_DELAY/2);
+
+ uint8_t checksum_computed = 0;
+ for (int i = 0; i < SERIAL_MASTER_BUFFER_LENGTH; ++i) {
+ serial_master_buffer[i] = serial_read_byte();
+ sync_send();
+ checksum_computed += serial_master_buffer[i];
+ }
+ 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;
+ }
+}
+
+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
+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(1);
+
+ // wait for the slaves response
+ serial_input();
+ serial_high();
+ _delay_us(SERIAL_DELAY);
+
+ // check if the slave is present
+ if (serial_read_pin()) {
+ // slave failed to pull the line low, assume not present
+ sei();
+ return 1;
+ }
+
+ // 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();
+ checksum_computed += serial_slave_buffer[i];
+ }
+ uint8_t checksum_received = serial_read_byte();
+ sync_recv();
+
+ if (checksum_computed != checksum_received) {
+ sei();
+ return 1;
+ }
+
+ uint8_t checksum = 0;
+ // send data to the slave
+ for (int i = 0; i < SERIAL_MASTER_BUFFER_LENGTH; ++i) {
+ serial_write_byte(serial_master_buffer[i]);
+ sync_recv();
+ checksum += serial_master_buffer[i];
+ }
+ serial_write_byte(checksum);
+ sync_recv();
+
+ // always, release the line when not in use
+ serial_output();
+ serial_high();
+
+ sei();
+ return 0;
+}
+
+#endif
projects / qmk_firmware.git / blobdiff