RS485

Hello, The code as follows. Sorry for the inconvenience.
void uart_rs485(void)
{ SCU_PinConfigure(2,3, SCU_CFG_MODE_FUNC2);// p2_3 for U3_TXD
SCU_PinConfigure(2,4, SCU_CFG_MODE_FUNC2);// p2_4 for U3_RXD GPIO_SetDir(4,11,GPIO_DIR_OUTPUT);// Set GIO_B1_RS485_DIR as output

LPC_USART3->LCR = 0x83;// Line Control Register
LPC_USART3->FCR =0x07;//FIFO buffer
LPC_USART3->FDR =0;// Fractional Divide
LPC_USART3->DLM =0;//Divide Latch MSB
LPC_USART3->DLL =98;//Divide Latch LSB
LPC_USART3->LCR =0x03;//Disable DLAB

}
void uart_rs485_transmit(void)
{ GPIO_PinWrite(4,11,1);//Making Transmit Enable high
if(LPC_USART3->LSR & 0x20)
{ LPC_USART3->THR = 83;
} }

void uart_rs485_receive(void)
{ GPIO_PinWrite(4,11,0);//Receive Enable
a = LPC_USART3->RBR;
}

Hello, The code as follows. Sorry for the inconvenience.
void uart_rs485(void)
{ SCU_PinConfigure(2,3, SCU_CFG_MODE_FUNC2);// p2_3 for U3_TXD
SCU_PinConfigure(2,4, SCU_CFG_MODE_FUNC2);// p2_4 for U3_RXD GPIO_SetDir(4,11,GPIO_DIR_OUTPUT);// Set GIO_B1_RS485_DIR as output

LPC_USART3->LCR = 0x83;// Line Control Register
LPC_USART3->FCR =0x07;//FIFO buffer
LPC_USART3->FDR =0;// Fractional Divide
LPC_USART3->DLM =0;//Divide Latch MSB
LPC_USART3->DLL =98;//Divide Latch LSB
LPC_USART3->LCR =0x03;//Disable DLAB

}
void uart_rs485_transmit(void)
{ GPIO_PinWrite(4,11,1);//Making Transmit Enable high
if(LPC_USART3->LSR & 0x20)
{ LPC_USART3->THR = 83;
} }

void uart_rs485_receive(void)
{ GPIO_PinWrite(4,11,0);//Receive Enable
a = LPC_USART3->RBR;
}

Hi Rajesh,
I have a request to you. Please read the each and every line of the answers you get here. If it is not understandable in first read then read it again and again until it is completely making sense to you. yes sometimes it is difficult for us because of the too much english they use in the answers ;).

So from the first response your questions Andy,

Whoever trying to help you here did not find your post as well presented as they like every professionals do. Again too much expectations on us right..
Your code look like you have a map on scribbles. So he is trying to help you to improve in that area. It is not technically solving your URGENT problem. But believe me you will be needing that anytime soon in your career.

Next, from the second answer you got from B Carutt,
He asking you to uncomment an important line which seems to directly linked to your problem statement. But he also asking you to check the criticality of all other commented lines because he thinks those commented lines seem to be more than just comments.

Next, From the third answer you got from Westonsupermare Pier,
I do not understand the meaning of the sarcasm. If it same to you then just ignore that answer.

Next, from your response,
you did some clean up in your copy pasted code. And added some proper(I assume) register settings. But you failed to mention many information here. They do not know what is the result after you modified the code such as 1.Even after your code change still not able to load the FCR reg? and many more may be (i.e micro, hardware info, details of testing method etc).

And a final note from me, in this forum you do not get the right answers always but always learn something if you're willing. I was once in your shoes.

The chip I am using is LPC1857

void uart_rs485(void)
{ SCU_PinConfigure(2,3, SCU_CFG_MODE_FUNC2);
SCU_PinConfigure(2,4, SCU_CFG_MODE_FUNC2);
GPIO_SetDir(4,11,GPIO_DIR_OUTPUT);
LPC_USART3->LCR = 0x83;
LPC_USART3->FCR =0x07;
LPC_USART3->FDR =0;
LPC_USART3->DLM =0;
LPC_USART3->DLL =98;
LPC_USART3->LCR =0x03;

}
void uart_rs485_transmit(void)
{ GPIO_PinWrite(4,11,1);//Making Transmit Enable high
if(LPC_USART3->LSR & 0x20)
{ LPC_USART3->THR = 83;
} }

void uart_rs485_receive(void)
{ GPIO_PinWrite(4,11,0);//Receive Enable
a = LPC_USART3->RBR;
}

So you really don't believe in indentation for 'C' source code?

Sorry Neil, What you meant by this identation

K. I am following the above told identation.

Hello, Let me know about the PCLK value that should be given for UART communication. How to assign PCLK in mdk5

Hi Dharmaraj, Thanks a lot.I will check that link you have shared.

Hi Dharmaraj, I have gone through all the sample codes given. But I didnt get any match codes for UART communication. USB and I2C coomunications are similar to RS485?

Hi all, While dealing with UART1 of LPC1857 to be used as RS232 I have coded as below.
For providing clock:

void SCI_PortClock (uint32_t clock) {
  if (clock) {
    LPC_CCU1->CLK_M3_UART1_CFG |= 3;
    while (!(LPC_CCU1->CLK_M3_UART1_STAT & 1));
  }
  else {
    LPC_CCU1->CLK_M3_UART1_CFG   &= ~(3);
    while (LPC_CCU1->CLK_M3_UART1_STAT & 1);
  }
}

Pin configuration and UART configuration:

RS232 PINS
U1_TXD = P3_4
U1_RXD = P3_5
*/
const PIN_ID RS232_PIN[] = {
  { RTE_UART1_RX_PORT, RTE_UART1_RX_BIT, (RTE_UART1_RX_FUNC | SCU_SFS_EZI)},
  { RTE_UART1_TX_PORT, RTE_UART1_TX_BIT, (RTE_UART1_TX_FUNC)}
};


void uart_sci(void)
{
        const PIN_ID *pin;
        SCI_PortClock (1);
        for (pin = RS232_PIN; pin != &RS232_PIN[sizeof(RS232_PIN)/sizeof(PIN_ID)]; pin++) {
    if (pin->port == 0x10) {
      SCU_CLK_PinConfigure (pin->num, pin->config_val);
      continue;
    }
    SCU_PinConfigure(pin->port, pin->num, pin->config_val);
  }

        LPC_UART1->LCR = 0x83;     //Line Control Register
        LPC_UART1->FDR = 0;        //Fractional Divide
        LPC_UART1->DLM = 0;        //Divide Latch MSB
        LPC_UART1->DLL = 98;       //Divide Latch LSB
        LPC_UART1->LCR = 0x03;     //Disable DLAB
        LPC_UART1->FCR = 0x07;     //FIFO buffer
}
void uart_sci_transmit(void)
{

        if(LPC_UART1->LSR & 0x20)
        {
                LPC_UART1->THR = 83;
        }
}

void uart_sci_receive(void)
{

        a = LPC_UART1->RBR;
}

While debugging, I came to know that FCR, DLL, DLM are not configured as I have given.
Transmission and reception is unsuccessful. LCR is loaded properly. Inviting your valuable suggestions. I am using Keil MDK5.