Hi,
I'm exploring using UART idle interrupt on RX to signal to my application that data has arrived.
I currently push data into a tx queue then start transmission. I rely on uart tx ISRs to check if there is any more data to send, then load up a DMA transfer.
UART TE is enabled once when the UART is enabled. I then rely on DMA to do everything. This currently works very well.
Can anyone suggest how I could squeeze and idle frame in? Ideally an idle frame will be inserted after each call to uart_dma_send, eg once per item in the transmit queue. My aim would be to keep my current transmit setup, where I can keep shoveling data into the transmit queue. Im using STM32F745. Probably I've missed something in the datasheet..
TX currently looks like:
void interface_uart_send_stuff(if_uart_t* p, uint8_t* stuff, uint16_t length) {
tx_q_push(p, length, stuff);
if (tx_state_is_busy()) {
// TX already happening, just queue up more to send
return;
}
// Start tx
tx_q_dta_t tx = tx_q_popI(&p->tx_q);
uart_dma_send(p->uart_dev, tx.n, tx.d);
}
// TX end of dma interrupt. Pack more data if needed
void interface_uart_tx_end_isr(if_uart_t* p) {
if (tx_q_sizeI(&p->tx_q) > 0) {
tx_q_dta_t tx = tx_q_popI(&p->tx_q);
// Send by DMA data d, length n
uart_dma_send(p->uart_dev, tx.n, tx.d);
} else {
// We enable the TC interrupt here so that is only called on the last DMA transfer
// from the transmit queue
p->uart_dev->uart->CR1 |= USART_CR1_TCIE;
}
}
// End of physical transmission interrupt
void interface_uart_tx_eot_isr(if_uart_t* p) {
if (tx_q_sizeI(&p->tx_q) > 0) {
tx_q_dta_t tx = tx_q_popI(&p->tx_q);
uart_dma_send(p->uart_dev, tx.n, tx.d);
} else {
tx_next_state(p, tx_ready_s);
}
}
