topic Re: I am using MKL17z microcontroller and trying to implement Data transmission uing UART (RS485),but the data register UART2_D is empty in Kinetis Microcontrollers

I am using MKL17z microcontroller and trying to implement Data transmission uing UART (RS485),but the data register UART2_D is empty

priyankavorugan — Thu, 22 Sep 2016 06:03:53 GMT

I have implemented the code as mentioned below.Please let me if i missed any initializations.

Note:

I have used the following code.
PTE22 is TX
PTE23 is RX

void uart2_init(void)
{
SIM_SCGC4 |= SIM_SCGC4_UART2_MASK;
GPIOE_PDDR |= 0x00400000; //Tx as output and x as input.
PORTD_PCR22 = PORT_PCR_MUX(0x3u); //chip specific
PORTD_PCR23 = PORT_PCR_MUX(0x3u);

UART2_C1 = 0x00; //8bit data,start bit and stop bit ,no parity

UART2_C2 = 0x00; Tx off Rx off

sbr = ((24*1000000) /(16 * 9600)); BUS clock is 24Mhz ,and baud rate is 9600
brfa = (((24*1000000*32)/(9600*16)) - ((sbr) * 32));

UART2_BDH |= 0x00;
UART2_BDL = ((U8)(sbr));
UART2_C4 |= ((U8)(brfa));

(void)UART2_S1; // to clear TX_DATA_REG_EMPTY_FLAG ,TRANSMIT_COMPLETE_FLAG
(void)UART2_D;

UART2_C2 = 0x0C; // TX RX On
}

void transmit_data(U8 Buffer_data)
{
while((UART2_S1 & UART_S1_TDRE_MASK)==0); // Wait for transmit buffer to be empty
(void)UART2_S1; // Read UART2_S1 register to clear TDRE
UART2_D=Buffer_data; // Send data
}

void main(void)
{
while(TRUE)
{
transmit_data(0x01);
}
}

Re: I am using MKL17z microcontroller and trying to implement Data transmission uing UART (RS485),but the data register UART2_D is empty

xiangjun_rong — Mon, 26 Sep 2016 03:09:42 GMT

Hi,

I suppose you should use the foolwoing code:

SIM_SCGC5|=0x2000; //set PORTE clock

PORTE_PCR22 = PORT_PCR_MUX(0x4u); //It is PORTE instead of PORTD and ALT4 instead of ALT3
PORTE_PCR23 = PORT_PCR_MUX(0x4u);

SIM_SCGC4 |= SIM_SCGC4_UART2_MASK;

Pls use the above setting and have a try.

XiangJun Rong

Re: I am using MKL17z microcontroller and trying to implement Data transmission uing UART (RS485),but the data register UART2_D is empty

priyankavorugan — Mon, 26 Sep 2016 03:58:47 GMT

Hi xiangjun.rong ,

After posting the issue i noticed that it should be ALT4 and not ALT3.So i changed that configurations and my UART is working properly.

Thankyou.