LPC MicrocontrollersのトピックRe: Sending a byte using UART

Sending a byte using UART

emimad — Sun, 19 Sep 2021 18:51:05 GMT

Hi all!

I'm trying to send some bytes through UART but I'm having some problems, probably because my old programming memories.

uint8_t array[]={0x80, 0x30, 0x31, 0x50};

for(i=0;i<4;i++){

Chip_UART_SendByte(LPC_USART, array[i]);

}

I'm sure it's an stupid question... but after check many examples I can't send my array byte by byte

Thanks in advance!

Re: Sending a byte using UART

diego_charles — Mon, 20 Sep 2021 21:33:50 GMT

Hi @emimad

I hope you are doing well!

Could you let me know which LPC board/MCU and LPC drivers are you using?

Are you able to see any part of your transmitted data array in the TX pin? Or fails completely?

As a quick comment, I would better call that function as below :

/* Transmit a byte array through the UART peripheral (non-blocking) */ int Chip_UART_Send(LPC_USART_T *pUART, const void *data, int numBytes) { int sent = 0; uint8_t *p8 = (uint8_t *) data; /* Send until the transmit FIFO is full or out of bytes */ while ((sent < numBytes) && ((Chip_UART_ReadLineStatus(pUART) & UART_LSR_THRE) != 0)) { Chip_UART_SendByte(pUART, *p8); p8++; sent++; } return sent; }

This is done in the LPC4347 LPCopen drivers.

And make sure that the RX pins and the UART are properly clocked and configured as the UM mentions.

All the best ,

Diego.

Re: Sending a byte using UART

emimad — Tue, 21 Sep 2021 13:48:21 GMT

Thank you Diego!

I'm using a LPCXpresso LPC1347 board with MCUXpresso IDE v11.4.0 and LPCOpen v2.05.

I tried your function:

uint8_t array[]={0x80, 0x30, 0x31, 0x50};

Chip_UART_Send(LPC_USART, "UART_Send!\n\r", 12);
Chip_UART_Send(LPC_USART, (const uint8_t *) &array[i], 10);
Chip_UART_Send(LPC_USART, (const uint8_t *) array[i], 10);

Chip_UART_SendBlocking(LPC_USART, "\n\rUART_SendBlocking\n\r", 21);
Chip_UART_SendBlocking(LPC_USART, (const uint8_t *) &array[i], 10);
Chip_UART_SendBlocking(LPC_USART, (const uint8_t *) array[i], 10);

/* Transmit a byte array through the UART peripheral (non-blocking) */
int Chip_UART_Send(LPC_USART_T *pUART, const void *data, int numBytes)
{
int sent = 0;
uint8_t *p8 = (uint8_t *) data;

/* Send until the transmit FIFO is full or out of bytes */
while ((sent < numBytes) && ((Chip_UART_ReadLineStatus(pUART) & UART_LSR_THRE) != 0))
{
Chip_UART_SendByte(pUART, *p8);
p8++;
sent++;
}

return sent;
}

/* Transmit a byte array through the UART peripheral (blocking) */
int Chip_UART_SendBlocking(LPC_USART_T *pUART, const void *data, int numBytes)
{
int pass, sent = 0;
uint8_t *p8 = (uint8_t *) data;

while (numBytes > 0) {
pass = Chip_UART_Send(pUART, p8, numBytes);
numBytes -= pass;
sent += pass;
p8 += pass;
}

return sent;
}

And this is the output:

Chip_UART_Send only sends the first character but not the first byte of my array