struct ao_fifo ao_usart_rx_fifo;
struct ao_fifo ao_usart_tx_fifo;
-uint8_t ao_usart_tx_started;
+uint8_t ao_usart_tx_avail;
+uint8_t ao_usart_tx_avail_min;
+
+#define LPC_USART_TX_FIFO_SIZE 16
void
ao_debug_out(char c)
static void
_ao_serial_tx_start(void)
{
- if (!ao_fifo_empty(ao_usart_tx_fifo) & !ao_usart_tx_started)
- {
- ao_usart_tx_started = 1;
+ if (!ao_fifo_empty(ao_usart_tx_fifo) && ao_usart_tx_avail) {
+ ao_usart_tx_avail--;
+ if (ao_usart_tx_avail < ao_usart_tx_avail_min)
+ ao_usart_tx_avail_min = ao_usart_tx_avail;
ao_fifo_remove(ao_usart_tx_fifo, lpc_usart.rbr_thr);
}
}
ao_wakeup(&ao_stdin_ready);
}
if (lpc_usart.lsr & (1 << LPC_USART_LSR_THRE)) {
- ao_usart_tx_started = 0;
+ ao_usart_tx_avail = LPC_USART_TX_FIFO_SIZE;
_ao_serial_tx_start();
ao_wakeup(&ao_usart_tx_fifo);
}
(1 << LPC_USART_FCR_TXFIFORES) |
(LPC_USART_FCR_RXTL_1 << LPC_USART_FCR_RXTL));
+ ao_usart_tx_avail = LPC_USART_TX_FIFO_SIZE;
+ ao_usart_tx_avail_min = LPC_USART_TX_FIFO_SIZE;
+
/* 8 n 1 */
lpc_usart.lcr = ((LPC_USART_LCR_WLS_8 << LPC_USART_LCR_WLS) |
(LPC_USART_LCR_SBS_1 << LPC_USART_LCR_SBS) |