LPC1769 to LPC1769 UART COMMUNICATION

[lpcware]

Content originally posted in LPCWare by handthepig on Fri Jun 14 04:52:50 MST 2013
Hi all,

I'm trying to use a LPC1769 to communicate with another using UART.

I'm using UART2  (TXD2,RXD2)P0.10,P0.11 respectively. I just connected directly from the LPC1 (RXD2) to the LPC2 (TXD2) and LPC1(TXD2) to the LPC2 (RXD2).

I connected a push button to P2.12 of LPC1 and tried to send a data via UART to LPC2 to on a LED on P2.12. However it does not seem to work. Can someone help me? Sorry I'm new to LPC1769.

LPC 1 :

#include <stdio.h>
#include "lpc_types.h"
#include "lpc17xx_clkpwr.h"
#include "lpc17xx_gpio.h"
#include "lpc17xx_uart.h"
#include "lpc17xx_libcfg_default.h"
#include "lpc17xx_pinsel.h"
#include "lpc17xx_nvic.h"
#include<string.h>

void Init_GPIO(void)
{
        PINSEL_CFG_Type PinCfg2A;
        PinCfg2A.Funcnum = 0;
        PinCfg2A.OpenDrain=0;
        PinCfg2A.Pinmode=0;
        PinCfg2A.Portnum = 2;
        PinCfg2A.Pinnum = 12;
        PINSEL_ConfigPin (&PinCfg2A);   //pushbutton
}

/*------------------------------*/
/*---------Pinsel UART2---------*/
void pinsel_uart2(void)
{
        PINSEL_CFG_Type PinCfg;
        PinCfg.Funcnum = 1;
        PinCfg.OpenDrain=0;
        PinCfg.Portnum = 0;
        PinCfg.Pinnum = 10;
        PINSEL_ConfigPin (&PinCfg);   //transmitter
        PinCfg.Pinnum = 11;
        PINSEL_ConfigPin (&PinCfg);   //receiver
}
/*---------Pinsel UART2---------*/
/*------------------------------*/
/*------------------------------------------*/
/*---------Initialise UART---------*/
void Init_UART(void)
{
        UART_CFG_Type uartCfg;
        uartCfg.Baud_rate = 115200;
        uartCfg.Databits = UART_DATABIT_8;
        uartCfg.Parity = UART_PARITY_NONE;
        uartCfg.Stopbits = UART_STOPBIT_1;
        //Pin select for uart2
        pinsel_uart2();
        //Supply power & setup working par.s for uart2
        UART_Init(LPC_UART2, &uartCfg);
}
/*-----------------*/
/*------------------------------------------*/

int main(void)
{
SystemInit();
Init_GPIO();
Init_UART();//Initialise UART
int btn=1;
uint8_t Buffer[] = "1";
pinsel_uart2();
GPIO_SetDir(2, 1<<12, 0);//Configure Pin 2.12 as input pin
GPIO_SetDir(0, 1<<10, 1);//Output from UART P0.10
GPIO_SetDir(0, 1<<11, 0);//Input from UART P0.11
while(1)
{
btn = ((GPIO_ReadValue(2) >> 12) & 0x01);//btn to ground
if(btn==0)
{
UART_Send(LPC_UART2,(uint8_t *)Buffer,strlen(Buffer),NONE_BLOCKING );
}
}
}


LPC 2:



#include <stdio.h>
#include "lpc_types.h"
#include "lpc17xx_clkpwr.h"
#include "lpc17xx_gpio.h"
#include "lpc17xx_uart.h"
#include "lpc17xx_libcfg_default.h"
#include "lpc17xx_pinsel.h"
#include "lpc17xx_nvic.h"
#include<string.h>

void Init_GPIO(void)
{
        PINSEL_CFG_Type PinCfg2A;
        PinCfg2A.Funcnum = 0;
        PinCfg2A.OpenDrain=0;
        PinCfg2A.Pinmode=0;
        PinCfg2A.Portnum = 2;
        PinCfg2A.Pinnum = 12;
        PINSEL_ConfigPin (&PinCfg2A);   //pushbutton
}

/*------------------------------*/
/*---------Pinsel UART2---------*/
void pinsel_uart2(void)
{
        PINSEL_CFG_Type PinCfg;
        PinCfg.Funcnum = 1;
        PinCfg.OpenDrain=0;
        PinCfg.Portnum = 0;
        PinCfg.Pinnum = 10;
        PINSEL_ConfigPin (&PinCfg);   //transmitter
        PinCfg.Pinnum = 11;
        PINSEL_ConfigPin (&PinCfg);   //receiver
}
/*---------Pinsel UART2---------*/
/*------------------------------*/
/*------------------------------------------*/
/*---------Initialise UART---------*/
void Init_UART(void)
{
        UART_CFG_Type uartCfg;
        uartCfg.Baud_rate = 115200;
        uartCfg.Databits = UART_DATABIT_8;
        uartCfg.Parity = UART_PARITY_NONE;
        uartCfg.Stopbits = UART_STOPBIT_1;
        //Pin select for uart2
        pinsel_uart2();
        //Supply power & setup working par.s for uart2
        UART_Init(LPC_UART2, &uartCfg);
}
/*-----------------*/
/*------------------------------------------*/

int main(void)
{
SystemInit();
Init_GPIO();
Init_UART();//Initialise UART
uint8_t Buffer;
pinsel_uart2();
GPIO_SetDir(2, 1<<12, 0);//Configure Pin 2.12 as input pin
GPIO_SetDir(0, 1<<10, 1);//Output from UART P0.10
GPIO_SetDir(0, 1<<11, 0);//Input from UART P0.11
while(1)
{
GPIO_ClearValue(2, 1<<12);
UART_Receive(LPC_UART2, &Buffer, 1, NONE_BLOCKING);//Check first char
if (Buffer=='1')
{
GPIO_SetValue(2, 1<<12);
}
}
}



Can someone help me? I'm currently doing it for a project and i dont have much time left.

Thank you!!!

[lpcware]

Content originally posted in LPCWare by handthepig on Mon Jun 17 05:27:02 MST 2013
Hi,

using a RS232 to usb connection, i used tera terminal to test the transmission of data.And it did not seem to work. The connection for LPC to RS 232 i used is the RX,TXD and gnd (pins 2,3,5) pins, which is connected to the MAX233 and to the lpc.

[lpcware]

Content originally posted in LPCWare by vasanth on Sun Jun 16 10:46:40 MST 2013
Have you tested each LPC separately?
1) Take the first one and connect it to a standard serial port of a PC. You need a voltage level converter such as MAX3232 for that. Or a USB-UART bridge if you want to connect to a USB port.
2) Use a PC application such as hyperterminal (in windows) and check the data transmission and reception. Then repeat the test for the second LPC in a similar way.
3) If they do work like you expected, then it is time to connect both LPCs in the following manner.

LPC1-----               LPC2

  Tx       ---------      Rx
  Rx        ---------      Tx
Gnd     -------    Gnd

and it should work. :)

[lpcware]

Content originally posted in LPCWare by handthepig on Sat Jun 15 21:45:51 MST 2013

---

Quote: vasanth
Check your physical connection first. Ensure that the two microcontrollers have a common ground which means GND pin of LPC1 must be in connection with GND pin of LPC2.

---

i've checked the connections over and over again. everything seems to be fine. Is it the correct way to connect the LPC 1 RXD2 to TXD2 of LPC 2 and vice versa?

[lpcware]

Content originally posted in LPCWare by vasanth on Sat Jun 15 21:13:11 MST 2013
Check your physical connection first. Ensure that the two microcontrollers have a common ground which means GND pin of LPC1 must be in connection with GND pin of LPC2.

[lpcware]

Content originally posted in LPCWare by handthepig on Sat Jun 15 03:55:24 MST 2013
Hi, thanks for the quick reply. I'm still facing the same problem despite adding a delay. Below is my updated code:

LPC 1:
#include <stdio.h>
#include "lpc_types.h"
#include "lpc17xx_clkpwr.h"
#include "lpc17xx_gpio.h"
#include "lpc17xx_uart.h"
#include "lpc17xx_libcfg_default.h"
#include "lpc17xx_pinsel.h"
#include "lpc17xx_nvic.h"
#include<string.h>

void Init_GPIO(void)
{
        PINSEL_CFG_Type PinCfg2A;
        PinCfg2A.Funcnum = 0;
        PinCfg2A.OpenDrain=0;
        PinCfg2A.Pinmode=0;
        PinCfg2A.Portnum = 2;
        PinCfg2A.Pinnum = 12;
        PINSEL_ConfigPin (&PinCfg2A);   //pushbutton
}

/*------------------------------*/
/*---------Pinsel UART2---------*/
void pinsel_uart2(void)
{
        PINSEL_CFG_Type PinCfg;
        PinCfg.Funcnum = 1;
        PinCfg.OpenDrain=0;
        PinCfg.Portnum = 0;
        PinCfg.Pinnum = 10;
        PINSEL_ConfigPin (&PinCfg);   //transmitter
        PinCfg.Pinnum = 11;
        PINSEL_ConfigPin (&PinCfg);   //receiver
}
/*---------Pinsel UART2---------*/
/*------------------------------*/
/*------------------------------------------*/
/*---------Initialise UART---------*/
void Init_UART(void)
{
        UART_CFG_Type uartCfg;
        uartCfg.Baud_rate = 115200;
        uartCfg.Databits = UART_DATABIT_8;
        uartCfg.Parity = UART_PARITY_NONE;
        uartCfg.Stopbits = UART_STOPBIT_1;
        //Pin select for uart2
        pinsel_uart2();
        //Supply power & setup working par.s for uart2
        UART_Init(LPC_UART2, &uartCfg);
}
/*-----------------*/
/*------------------------------------------*/

int main(void)
{
SystemInit();
Init_GPIO();
Init_UART();//Initialise UART
int btn=1;
uint8_t Buffer[] = "1";
GPIO_SetDir(2, 1<<12, 0);//Configure Pin 2.12 as input pin
GPIO_SetDir(0, 1<<10, 1);//Output from UART P0.10
GPIO_SetDir(0, 1<<11, 0);//Input from UART P0.11
while(1)
{
//printf("%s\n\r",Buffer);
btn = ((GPIO_ReadValue(2) >> 12) & 0x01);//btn to ground
if(btn==0)
{
UART_Send(LPC_UART2,(uint8_t *)Buffer,strlen(Buffer),NONE_BLOCKING );
}
}
}



LPC 2:




#include <stdio.h>
#include "lpc_types.h"
#include "lpc17xx_clkpwr.h"
#include "lpc17xx_gpio.h"
#include "lpc17xx_uart.h"
#include "lpc17xx_libcfg_default.h"
#include "lpc17xx_pinsel.h"
#include "lpc17xx_nvic.h"
#include<string.h>

void Init_GPIO(void)
{
        PINSEL_CFG_Type PinCfg2A;
        PinCfg2A.Funcnum = 0;
        PinCfg2A.OpenDrain=0;
        PinCfg2A.Pinmode=0;
        PinCfg2A.Portnum = 2;
        PinCfg2A.Pinnum = 12;
        PINSEL_ConfigPin (&PinCfg2A);   //pushbutton
}

/*------------------------------*/
/*---------Pinsel UART2---------*/
void pinsel_uart2(void)
{
        PINSEL_CFG_Type PinCfg;
        PinCfg.Funcnum = 1;
        PinCfg.OpenDrain=0;
        PinCfg.Portnum = 0;
        PinCfg.Pinnum = 10;
        PINSEL_ConfigPin (&PinCfg);   //transmitter
        PinCfg.Pinnum = 11;
        PINSEL_ConfigPin (&PinCfg);   //receiver
}
/*---------Pinsel UART2---------*/
/*------------------------------*/
/*------------------------------------------*/
/*---------Initialise UART---------*/
void Init_UART(void)
{
        UART_CFG_Type uartCfg;
        uartCfg.Baud_rate = 115200;
        uartCfg.Databits = UART_DATABIT_8;
        uartCfg.Parity = UART_PARITY_NONE;
        uartCfg.Stopbits = UART_STOPBIT_1;
        //Pin select for uart2
        pinsel_uart2();
        //Supply power & setup working par.s for uart2
        UART_Init(LPC_UART2, &uartCfg);
}
/*-----------------*/
/*------------------------------------------*/

int main(void)
{
SystemInit();
Init_GPIO();
Init_UART();//Initialise UART
uint8_t Buffer;
GPIO_SetDir(2, 1<<12, 1);//Configure Pin 2.12 as output pin
GPIO_SetDir(0, 1<<10, 1);//Output from UART P0.10
GPIO_SetDir(0, 1<<11, 0);//Input from UART P0.11
while(1)
{
GPIO_ClearValue(2, 1<<12);
UART_Receive(LPC_UART2, &Buffer, 1, NONE_BLOCKING);//Check first char
if (Buffer=="1" )
{
GPIO_SetValue(2, 1<<12);
Timer0_Wait(1000);
}
}
}

[lpcware]

Content originally posted in LPCWare by vasanth on Fri Jun 14 23:30:42 MST 2013

    while(1)
    {
        GPIO_ClearValue(2, 1<<12);
        UART_Receive(LPC_UART2, &Buffer, 1, NONE_BLOCKING);    //Check first char
        if (Buffer=='1')
        {
             GPIO_SetValue(2, 1<<12);
             delay_1sec();   // add something like this
        }
    }

Provide some delay like above to make the LED light visible. Otherwise you might be clearing the LED immediately after setting it. Oops.:eek:

[lpcware]

Content originally posted in LPCWare by vasanth on Fri Jun 14 23:23:01 MST 2013

while(1)
{
        GPIO_ClearValue(2, 1<<12);
        UART_Receive(LPC_UART2, &Buffer, 1, NONE_BLOCKING);//Check first char
        if (Buffer=='1')
        {
             GPIO_SetValue(2, 1<<12);
             [COLOR = RED]
             delay_1sec();
             [/COLOR]
        }
}

Add some delay like above to make the LED light visible. Otherwise you might be clearing the LED immediately after setting it.

[lpcware]

Content originally posted in LPCWare by handthepig on Fri Jun 14 20:17:22 MST 2013
I've checked my UART_send and it seems that data is sent, i've tried printing Buffer to see the data to configure the UART_receive at LPC2.

[lpcware]

Content originally posted in LPCWare by handthepig on Fri Jun 14 19:12:34 MST 2013

---

Quote: vasanth
Why are you configuring LED as input pin? :mad:

---

whoops there was a typo, i've changed it but it still does not seem to work. Thanks for pointing it out :)

[lpcware]

Content originally posted in LPCWare by vasanth on Fri Jun 14 07:51:29 MST 2013

---

Quote:

GPIO_SetDir(2, 1<<12, 0);//Configure Pin 2.12 as input pin

---

Why are you configuring LED as input pin? :mad:

[lpcware]

Content originally posted in LPCWare by handthepig on Fri Jun 14 07:08:11 MST 2013
Someone please help?  :'(