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@@ -51,9 +51,10 @@ POSSIBILITY OF SUCH DAMAGE.
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void serial_init(void)
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{
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SERIAL_RXD_INIT();
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+ SERIAL_TXD_INIT();
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}
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-// RX ring buffer
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+/* RX ring buffer */
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#define RBUF_SIZE 8
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static uint8_t rbuf[RBUF_SIZE];
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static uint8_t rbuf_head = 0;
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@@ -71,39 +72,63 @@ uint8_t serial_recv(void)
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return data;
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}
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-//ISR(INT2_vect)
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+void serial_send(uint8_t data)
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+{
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+ /* signal state: IDLE: ON, START: OFF, STOP: ON, DATA0: OFF, DATA1: ON */
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+ /* start bit */
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+ SERIAL_TXD_OFF();
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+ _delay_us(WAIT_US);
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+
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+#ifdef SERIAL_BIT_ORDER_MSB
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+ uint8_t mask = 0x80;
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+#else
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+ uint8_t mask = 0x01;
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+#endif
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+ while (mask) {
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+ if (data&mask) { SERIAL_TXD_ON(); } else { SERIAL_TXD_OFF(); }
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+ _delay_us(WAIT_US);
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+
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+#ifdef SERIAL_BIT_ORDER_MSB
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+ mask >>= 1;
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+#else
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+ mask <<= 1;
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+#endif
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+ }
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+
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+ /* stop bit */
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+ SERIAL_TXD_ON();
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+ _delay_us(WAIT_US);
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+}
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+
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+/* detect edge of start bit */
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ISR(SERIAL_RXD_VECT)
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{
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SERIAL_RXD_INT_ENTER()
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uint8_t data = 0;
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#ifdef SERIAL_BIT_ORDER_MSB
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- uint8_t pos = 0x80;
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+ uint8_t mask = 0x80;
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#else
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- uint8_t pos = 0x01;
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+ uint8_t mask = 0x01;
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#endif
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- // to center of start bit
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+ /* to center of start bit */
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_delay_us(WAIT_US/2);
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do {
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- // to center of next bit
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+ /* to center of next bit */
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_delay_us(WAIT_US);
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- if (SERIAL_RXD_PIN&(1<<SERIAL_RXD_BIT)) {
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- data |= pos;
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+ if (SERIAL_RXD_READ()) {
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+ data |= mask;
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}
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#ifdef SERIAL_BIT_ORDER_MSB
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- pos >>= 1;
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+ mask >>= 1;
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#else
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- pos <<= 1;
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+ mask <<= 1;
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#endif
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- } while (pos);
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- // to center of stop bit
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+ } while (mask);
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+ /* to center of stop bit */
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_delay_us(WAIT_US);
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-#ifdef SERIAL_NEGATIVE_LOGIC
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- data = ~data;
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-#endif
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-
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uint8_t next = (rbuf_head + 1) % RBUF_SIZE;
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if (next != rbuf_tail) {
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rbuf[rbuf_head] = data;
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