* is still useful for negative logic signal like Sun protocol not supported by hardware USART.
*/
-#define WAIT_US (1000000/SERIAL_BAUD)
+#define WAIT_US (1000000L/SERIAL_BAUD)
+
+/* debug for signal timing, see debug pin with oscilloscope */
+#ifdef SERIAL_SOFT_DEBUG
+ #define SERIAL_SOFT_DEBUG_INIT() (DDRD |= 1<<7)
+ #define SERIAL_SOFT_DEBUG_TGL() (PORTD ^= 1<<7)
+#else
+ #define SERIAL_SOFT_DEBUG_INIT()
+ #define SERIAL_SOFT_DEBUG_TGL()
+#endif
+
void serial_init(void)
{
+ SERIAL_SOFT_DEBUG_INIT();
+
SERIAL_RXD_INIT();
+ SERIAL_TXD_INIT();
}
-// RX ring buffer
+/* RX ring buffer */
#define RBUF_SIZE 8
static uint8_t rbuf[RBUF_SIZE];
static uint8_t rbuf_head = 0;
static uint8_t rbuf_tail = 0;
+
uint8_t serial_recv(void)
{
uint8_t data = 0;
return data;
}
-//ISR(INT2_vect)
+int16_t serial_recv2(void)
+{
+ uint8_t data = 0;
+ if (rbuf_head == rbuf_tail) {
+ return -1;
+ }
+
+ data = rbuf[rbuf_tail];
+ rbuf_tail = (rbuf_tail + 1) % RBUF_SIZE;
+ return data;
+}
+
+void serial_send(uint8_t data)
+{
+ /* signal state: IDLE: ON, START: OFF, STOP: ON, DATA0: OFF, DATA1: ON */
+
+#ifdef SERIAL_BIT_ORDER_MSB
+ uint8_t mask = 0x80;
+#else
+ uint8_t mask = 0x01;
+#endif
+
+#ifdef SERIAL_PARITY_ODD
+ uint8_t parity = 1;
+#elif defined(SERIAL_PARITY_EVEN)
+ uint8_t parity = 0;
+#endif
+
+ /* start bit */
+ SERIAL_TXD_OFF();
+ _delay_us(WAIT_US-2);
+
+ while (mask) {
+ if (data&mask) {
+ SERIAL_TXD_ON();
+#if defined(SERIAL_PARITY_EVEN) || defined(SERIAL_PARITY_ODD)
+ parity ^= 1;
+#endif
+ } else {
+ SERIAL_TXD_OFF();
+ }
+ _delay_us(WAIT_US-2);
+
+#ifdef SERIAL_BIT_ORDER_MSB
+ mask >>= 1;
+#else
+ mask <<= 1;
+#endif
+ }
+
+#if defined(SERIAL_PARITY_EVEN) || defined(SERIAL_PARITY_ODD)
+ /* to center of parity bit */
+ if (parity) {
+ SERIAL_TXD_ON();
+ } else {
+ SERIAL_TXD_OFF();
+ }
+ _delay_us(WAIT_US-2);
+#endif
+
+ /* stop bit */
+ SERIAL_TXD_ON();
+ _delay_us(WAIT_US-2);
+}
+
+/* detect edge of start bit */
ISR(SERIAL_RXD_VECT)
{
+ SERIAL_SOFT_DEBUG_TGL()
SERIAL_RXD_INT_ENTER()
uint8_t data = 0;
+
#ifdef SERIAL_BIT_ORDER_MSB
- uint8_t pos = 0x80;
+ uint8_t mask = 0x80;
#else
- uint8_t pos = 0x01;
+ uint8_t mask = 0x01;
+#endif
+
+#ifdef SERIAL_PARITY_ODD
+ uint8_t parity = 0;
+#elif defined(SERIAL_PARITY_EVEN)
+ uint8_t parity = 1;
#endif
- // to center of start bit
+
+ /* to center of start bit */
_delay_us(WAIT_US/2);
+ SERIAL_SOFT_DEBUG_TGL()
do {
- // to center of next bit
+ /* to center of next bit */
_delay_us(WAIT_US);
- if (SERIAL_RXD_PIN&(1<<SERIAL_RXD_BIT)) {
- data |= pos;
+ SERIAL_SOFT_DEBUG_TGL()
+ if (SERIAL_RXD_READ()) {
+ data |= mask;
+#if defined(SERIAL_PARITY_EVEN) || defined(SERIAL_PARITY_ODD)
+ parity ^= 1;
+#endif
}
#ifdef SERIAL_BIT_ORDER_MSB
- pos >>= 1;
+ mask >>= 1;
#else
- pos <<= 1;
+ mask <<= 1;
#endif
- } while (pos);
- // to center of stop bit
- _delay_us(WAIT_US);
+ } while (mask);
-#ifdef SERIAL_NEGATIVE_LOGIC
- data = ~data;
+#if defined(SERIAL_PARITY_EVEN) || defined(SERIAL_PARITY_ODD)
+ /* to center of parity bit */
+ _delay_us(WAIT_US);
+ if (SERIAL_RXD_READ()) { parity ^= 1; }
+ SERIAL_SOFT_DEBUG_TGL()
#endif
+ /* to center of stop bit */
+ _delay_us(WAIT_US);
+
uint8_t next = (rbuf_head + 1) % RBUF_SIZE;
+#if defined(SERIAL_PARITY_EVEN) || defined(SERIAL_PARITY_ODD)
+ if (parity && next != rbuf_tail) {
+#else
if (next != rbuf_tail) {
+#endif
rbuf[rbuf_head] = data;
rbuf_head = next;
}
SERIAL_RXD_INT_EXIT();
+ SERIAL_SOFT_DEBUG_TGL()
}