* 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();
}
void serial_send(uint8_t data)
{
/* signal state: IDLE: ON, START: OFF, STOP: ON, DATA0: OFF, DATA1: ON */
- /* start bit */
- SERIAL_TXD_OFF();
- _delay_us(WAIT_US);
#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(); } else { SERIAL_TXD_OFF(); }
- _delay_us(WAIT_US);
+ 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;
#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);
+ _delay_us(WAIT_US-2);
}
/* detect edge of start bit */
ISR(SERIAL_RXD_VECT)
{
-PORTD ^= 1<<7;
+ SERIAL_SOFT_DEBUG_TGL()
SERIAL_RXD_INT_ENTER()
uint8_t data = 0;
#ifdef SERIAL_PARITY_ODD
uint8_t parity = 0;
-#else
+#elif defined(SERIAL_PARITY_EVEN)
uint8_t parity = 1;
#endif
/* to center of start bit */
_delay_us(WAIT_US/2);
-PORTD ^= 1<<7;
+ SERIAL_SOFT_DEBUG_TGL()
do {
/* to center of next bit */
_delay_us(WAIT_US);
-PORTD ^= 1<<7;
+ 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
mask >>= 1;
#endif
} while (mask);
+#if defined(SERIAL_PARITY_EVEN) || defined(SERIAL_PARITY_ODD)
/* to center of parity bit */
_delay_us(WAIT_US);
if (SERIAL_RXD_READ()) { parity ^= 1; }
-PORTD ^= 1<<7;
+ 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();
-PORTD ^= 1<<7;
+ SERIAL_SOFT_DEBUG_TGL()
}