topic Re: S32K144 Uart Receive Problem in S32K

S32K144 Uart Receive Problem

cabz — Mon, 26 Jun 2023 07:39:08 GMT

Hello Sirs,
I'm using the S32K144 sample cookbook for UART. The transmit function works fine however the receive doesn't work. I've debugged it a little and the program gets stuck in the line
while((LPUART1->STAT & LPUART_STAT_RDRF_MASK)>>LPUART_STAT_RDRF_SHIFT==0);

You can see in the attached photo, the character 'a' should've been echoed in the terminal, but its not.

The source code :
int main(void)
{
/*!
* Initialization:
* =======================
*/
WDOG_disable(); /* Disable WDOG */
SOSC_init_8MHz(); /* Initialize system oscilator for 8 MHz xtal */
SPLL_init_160MHz(); /* Initialize SPLL to 160 MHz with 8 MHz SOSC */
NormalRUNmode_80MHz(); /* Init clocks: 80 MHz sysclk & core, 40 MHz bus, 20 MHz flash */
PORT_init(); /* Configure ports */

LPUART1_init(); /* Initialize LPUART @ 9600*/
LPUART1_transmit_string("Running LPUART example\n\r"); /* Transmit char string */
LPUART1_transmit_string("Input character to echo...\n\r"); /* Transmit char string */

while(1)
{
LPUART1_transmit_char('>'); /* Transmit prompt character*/
LPUART1_receive_and_echo_char(); /* Wait for input char, receive & echo it*/
}
}

char LPUART1_receive_char(void) { /* Function to Receive single Char */
static char receive;
while((LPUART1->STAT & LPUART_STAT_RDRF_MASK)>>LPUART_STAT_RDRF_SHIFT==0);
/* Wait for received buffer to be full */
PTD->PCOR |= (1 << 0);
receive= LPUART1->DATA; /* Read received data*/
return receive;
}

void LPUART1_receive_and_echo_char(void) { /* Function to echo received char back */
char send = LPUART1_receive_char(); /* Receive Char */
LPUART1_transmit_char(send); /* Transmit same char back to the sender */
LPUART1_transmit_char('\n'); /* New line */
LPUART1_transmit_char('\r'); /* Return */
}

void LPUART1_init(void) /* Init. summary: 9600 baud, 1 stop bit, 8 bit format, no parity */
{
PCC->PCCn[PCC_LPUART1_INDEX] &= ~PCC_PCCn_CGC_MASK; /* Ensure clk disabled for config */
PCC->PCCn[PCC_LPUART1_INDEX] |= PCC_PCCn_PCS(2) /* Clock src=2 (SIRCDIV2_CLK) */
| PCC_PCCn_CGC_MASK; /* Enable clock for LPUART1 regs */

LPUART1->BAUD = LPUART_BAUD_SBR(0x34) | LPUART_BAUD_OSR(15);

LPUART1->CTRL = LPUART_CTRL_RE_MASK | LPUART_CTRL_TE_MASK;

}

Re: S32K144 Uart Receive Problem

Senlent — Mon, 26 Jun 2023 08:49:09 GMT

Hi@AllenGlen

You type the character 'a' and the device responds with ">a", isn't that normal?

Re: S32K144 Uart Receive Problem

cabz — Mon, 26 Jun 2023 09:02:57 GMT

no, the pink color signifies I sent it. The black color signifies I received it.

I should receive a black colored 'a' character.

Re: S32K144 Uart Receive Problem

Senlent — Mon, 26 Jun 2023 09:07:48 GMT

Hi@AllenGlen

Re: S32K144 Uart Receive Problem

cabz — Mon, 26 Jun 2023 09:21:43 GMT

do you think this is hardware problem sir?
I also see the CTS in your terminal is shining... what do you think it means

btw I'm using IAR, and this code is from its samples.

Re: S32K144 Uart Receive Problem

Senlent — Mon, 26 Jun 2023 09:22:41 GMT

Hi@AllenGlen

Very likely, I tested the "S32K144_Project_LPUART" routine, the result is normal

Re: S32K144 Uart Receive Problem

cabz — Mon, 26 Jun 2023 09:45:22 GMT

I've checked the 2 other boards, they also doesn't work...

Re: S32K144 Uart Receive Problem

Senlent — Mon, 26 Jun 2023 09:50:31 GMT

Hi@AllenGlen

Are you using S32K144EVB? The following is the code I tested, I don't see any difference.

/* * Copyright (c) 2014 - 2016, Freescale Semiconductor, Inc. * Copyright (c) 2016 - 2018, NXP. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * 1. Redistributions of source code must retain the above copyright notice, * this list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * * 3. Neither the name of the copyright holder nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY NXP "AS IS" AND ANY EXPRESSED OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL NXP OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF * THE POSSIBILITY OF SUCH DAMAGE. */ #include "device_registers.h" /* include peripheral declarations S32K144 */ #include "LPUART.h" void LPUART1_init(void) /* Init. summary: 9600 baud, 1 stop bit, 8 bit format, no parity */ { PCC->PCCn[PCC_LPUART1_INDEX] &= ~PCC_PCCn_CGC_MASK; /* Ensure clk disabled for config */ PCC->PCCn[PCC_LPUART1_INDEX] |= PCC_PCCn_PCS(0b010) /* Clock src=2 (SIRCDIV2_CLK) */ | PCC_PCCn_CGC_MASK; /* Enable clock for LPUART1 regs */ LPUART1->BAUD = LPUART_BAUD_SBR(0x34) /* Initialize for 9600 baud, 1 stop: */ |LPUART_BAUD_OSR(15); /* SBR=52 (0x34): baud divisor = 8M/9600/16 = ~52 */ /* OSR=15: Over sampling ratio = 15+1=16 */ /* SBNS=0: One stop bit */ /* BOTHEDGE=0: receiver samples only on rising edge */ /* M10=0: Rx and Tx use 7 to 9 bit data characters */ /* RESYNCDIS=0: Resync during rec'd data word supported */ /* LBKDIE, RXEDGIE=0: interrupts disable */ /* TDMAE, RDMAE, TDMAE=0: DMA requests disabled */ /* MAEN1, MAEN2, MATCFG=0: Match disabled */ LPUART1->CTRL = LPUART_CTRL_RE_MASK |LPUART_CTRL_TE_MASK; /* Enable transmitter & receiver, no parity, 8 bit char: */ /* RE=1: Receiver enabled */ /* TE=1: Transmitter enabled */ /* PE,PT=0: No hw parity generation or checking */ /* M7,M,R8T9,R9T8=0: 8-bit data characters*/ /* DOZEEN=0: LPUART enabled in Doze mode */ /* ORIE,NEIE,FEIE,PEIE,TIE,TCIE,RIE,ILIE,MA1IE,MA2IE=0: no IRQ*/ /* TxDIR=0: TxD pin is input if in single-wire mode */ /* TXINV=0: TRansmit data not inverted */ /* RWU,WAKE=0: normal operation; rcvr not in statndby */ /* IDLCFG=0: one idle character */ /* ILT=0: Idle char bit count starts after start bit */ /* SBK=0: Normal transmitter operation - no break char */ /* LOOPS,Rsrc=0: no loop back */ } void LPUART1_transmit_char(char send) { /* Function to Transmit single Char */ while((LPUART1->STAT & LPUART_STAT_TDRE_MASK)>>LPUART_STAT_TDRE_SHIFT==0); /* Wait for transmit buffer to be empty */ LPUART1->DATA=send; /* Send data */ } void LPUART1_transmit_string(char data_string[]) { /* Function to Transmit whole string */ uint32_t i=0; while(data_string[i] != '\0') { /* Send chars one at a time */ LPUART1_transmit_char(data_string[i]); i++; } } char LPUART1_receive_char(void) { /* Function to Receive single Char */ char receive; while((LPUART1->STAT & LPUART_STAT_RDRF_MASK)>>LPUART_STAT_RDRF_SHIFT==0); /* Wait for received buffer to be full */ receive= LPUART1->DATA; /* Read received data*/ return receive; } void LPUART1_receive_and_echo_char(void) { /* Function to echo received char back */ char send = LPUART1_receive_char(); /* Receive Char */ LPUART1_transmit_char(send); /* Transmit same char back to the sender */ LPUART1_transmit_char('\n'); /* New line */ LPUART1_transmit_char('\r'); /* Return */ }

Re: S32K144 Uart Receive Problem

cabz — Mon, 26 Jun 2023 09:55:08 GMT

yes sir,

I think my pin connections are also correct, PTC6, PTC7 and 3.3V and GND

Re: S32K144 Uart Receive Problem

Senlent — Tue, 27 Jun 2023 02:12:34 GMT

Hi@AllenGlen

ok, you don't need to connect like this, just use USB directly

Re: S32K144 Uart Receive Problem

cabz — Tue, 27 Jun 2023 10:08:18 GMT

It works now, the problem must've been the serial wire. Thank you ^3^