Stellaris - LM4F120H5QR - Changing/Using Different UART Modules - code based on stellarisware sample uart_echo.c

Erdem Varer

Other Parts Discussed in Thread: EK-TM4C123GXL

Hi; i have seen many post about this subject but none of them seems to help so i want to ask you all one more time.

i have stellaris laucnhpad and LM4F120H5QR . i used and succesfully ran the sample uart_echo.c . As you know it uses uart0. but i changed the code to use another uart modules such as uart1 or uart2, none of them working. I connect these ports to my computer via ftdi basic (3.3v) . here is the sample code that uses uart0 :

#include "inc/hw_ints.h"
#include "inc/hw_memmap.h"
#include "inc/hw_types.h"
#include "driverlib/debug.h"
#include "driverlib/fpu.h"
#include "driverlib/gpio.h"
#include "driverlib/interrupt.h"
#include "driverlib/pin_map.h"
#include "driverlib/rom.h"
#include "driverlib/sysctl.h"
#include "driverlib/uart.h"

//*****************************************************************************
//
//! \addtogroup example_list
//! <h1>UART Echo (uart_echo)</h1>
//!
//! This example application utilizes the UART to echo text. The first UART
//! (connected to the USB debug virtual serial port on the evaluation board)
//! will be configured in 115,200 baud, 8-n-1 mode. All characters received on
//! the UART are transmitted back to the UART.
//
//*****************************************************************************

//*****************************************************************************
//
// The error routine that is called if the driver library encounters an error.
//
//*****************************************************************************
#ifdef DEBUG
void
__error__(char *pcFilename, unsigned long ulLine)
{
}
#endif

//*****************************************************************************
//
// The UART interrupt handler.
//
//*****************************************************************************
void
UARTIntHandler(void)
{
unsigned long ulStatus;

//
// Get the interrrupt status.
//
ulStatus = ROM_UARTIntStatus(UART0_BASE, true);

//
// Clear the asserted interrupts.
//
ROM_UARTIntClear(UART0_BASE, ulStatus);

//
// Loop while there are characters in the receive FIFO.
//
while(ROM_UARTCharsAvail(UART0_BASE))
{
//
// Read the next character from the UART and write it back to the UART.
//
ROM_UARTCharPutNonBlocking(UART0_BASE,
ROM_UARTCharGetNonBlocking(UART0_BASE));

//
// Blink the LED to show a character transfer is occuring.
//
GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_2, GPIO_PIN_2);

//
// Delay for 1 millisecond. Each SysCtlDelay is about 3 clocks.
//
SysCtlDelay(SysCtlClockGet() / (1000 * 3));

//
// Turn off the LED
//
GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_2, 0);

}
}

//*****************************************************************************
//
// Send a string to the UART.
//
//*****************************************************************************
void
UARTSend(const unsigned char *pucBuffer, unsigned long ulCount)
{
//
// Loop while there are more characters to send.
//
while(ulCount--)
{
//
// Write the next character to the UART.
//
ROM_UARTCharPutNonBlocking(UART0_BASE, *pucBuffer++);
}
}

//*****************************************************************************
//
// This example demonstrates how to send a string of data to the UART.
//
//*****************************************************************************
int
main(void)
{
//
// Enable lazy stacking for interrupt handlers. This allows floating-point
// instructions to be used within interrupt handlers, but at the expense of
// extra stack usage.
//
ROM_FPUEnable();
ROM_FPULazyStackingEnable();

//
// Set the clocking to run directly from the crystal.
//
ROM_SysCtlClockSet(SYSCTL_SYSDIV_1 | SYSCTL_USE_OSC | SYSCTL_OSC_MAIN |
SYSCTL_XTAL_16MHZ);

//
// Enable the GPIO port that is used for the on-board LED.
//
ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOF);

//
// Enable the GPIO pins for the LED (PF2).
//
ROM_GPIOPinTypeGPIOOutput(GPIO_PORTF_BASE, GPIO_PIN_2);

//
// Enable the peripherals used by this example.
//
ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0);
ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);

//
// Enable processor interrupts.
//
ROM_IntMasterEnable();

//
// Set GPIO A0 and A1 as UART pins.
//
GPIOPinConfigure(GPIO_PA0_U0RX);
GPIOPinConfigure(GPIO_PA1_U0TX);
ROM_GPIOPinTypeUART(GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_1);

//
// Configure the UART for 115,200, 8-N-1 operation.
//
ROM_UARTConfigSetExpClk(UART0_BASE, ROM_SysCtlClockGet(), 115200,
(UART_CONFIG_WLEN_8 | UART_CONFIG_STOP_ONE |
UART_CONFIG_PAR_NONE));

//
// Enable the UART interrupt.
//
ROM_IntEnable(INT_UART0);
ROM_UARTIntEnable(UART0_BASE, UART_INT_RX | UART_INT_RT);

//
// Prompt for text to be entered.
//
UARTSend((unsigned char *)"\033[2JEnter text: ", 16);

//
// Loop forever echoing data through the UART.
//
while(1)
{
}
}

and here is my changed code to use uart1 :

//*****************************************************************************
//
// uart_echo.c - Example for reading data from and writing data to the UART in
// an interrupt driven fashion.
//
// Copyright (c) 2012 Texas Instruments Incorporated. All rights reserved.
// Software License Agreement
//
// Texas Instruments (TI) is supplying this software for use solely and
// exclusively on TI's microcontroller products. The software is owned by
// TI and/or its suppliers, and is protected under applicable copyright
// laws. You may not combine this software with "viral" open-source
// software in order to form a larger program.
//
// THIS SOFTWARE IS PROVIDED "AS IS" AND WITH ALL FAULTS.
// NO WARRANTIES, WHETHER EXPRESS, IMPLIED OR STATUTORY, INCLUDING, BUT
// NOT LIMITED TO, IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE APPLY TO THIS SOFTWARE. TI SHALL NOT, UNDER ANY
// CIRCUMSTANCES, BE LIABLE FOR SPECIAL, INCIDENTAL, OR CONSEQUENTIAL
// DAMAGES, FOR ANY REASON WHATSOEVER.
//
// This is part of revision 9453 of the EK-LM4F120XL Firmware Package.
//
//*****************************************************************************

//
// Get the interrrupt status.
//
ulStatus = ROM_UARTIntStatus(UART1_BASE, true);

//
// Clear the asserted interrupts.
//
ROM_UARTIntClear(UART1_BASE, ulStatus);

//
// Loop while there are characters in the receive FIFO.
//
while(ROM_UARTCharsAvail(UART1_BASE))
{
//
// Read the next character from the UART and write it back to the UART.
//
ROM_UARTCharPutNonBlocking(UART1_BASE,
ROM_UARTCharGetNonBlocking(UART1_BASE));

//
// Blink the LED to show a character transfer is occuring.
//
GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_2, GPIO_PIN_2);

//
// Delay for 1 millisecond. Each SysCtlDelay is about 3 clocks.
//
SysCtlDelay(SysCtlClockGet() / (1000 * 3));

//
// Turn off the LED
//
GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_2, 0);

}
}

//
// Set the clocking to run directly from the crystal.
//
ROM_SysCtlClockSet(SYSCTL_SYSDIV_1 | SYSCTL_USE_OSC | SYSCTL_OSC_MAIN |
SYSCTL_XTAL_16MHZ);

//
// Enable the GPIO port that is used for the on-board LED.
//
ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOF);

//
// Enable the GPIO pins for the LED (PF2).
//
ROM_GPIOPinTypeGPIOOutput(GPIO_PORTF_BASE, GPIO_PIN_2);

//
// Enable the peripherals used by this example.
//
ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_UART1);
ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOB);

//
// Enable processor interrupts.
//
ROM_IntMasterEnable();

//
// Set GPIO A0 and A1 as UART pins.
//
GPIOPinConfigure(GPIO_PB0_U1RX);
GPIOPinConfigure(GPIO_PB1_U1TX);
ROM_GPIOPinTypeUART(GPIO_PORTB_BASE, GPIO_PIN_0 | GPIO_PIN_1);

//
// Configure the UART for 115,200, 8-N-1 operation.
//
ROM_UARTConfigSetExpClk(UART1_BASE, ROM_SysCtlClockGet(), 115200,
(UART_CONFIG_WLEN_8 | UART_CONFIG_STOP_ONE |
UART_CONFIG_PAR_NONE));

//
// Enable the UART interrupt.
//
ROM_IntEnable(INT_UART1);
ROM_UARTIntEnable(UART1_BASE, UART_INT_RX | UART_INT_RT);

//
// Prompt for text to be entered.
//
UARTSend((unsigned char *)"\033[2JEnter text: ", 16);

//
// Loop forever echoing data through the UART.
//

while(1)
{

}
}

what am i missing?? Thanks for answers.

Erdem

over 11 years ago

0 Markel Robregado over 11 years ago

Guru 86235 points

Hi Erdem,

I don't see anything wrong with your uart_echo code using UART1. Did you setup UARTIntHandler() at your startup file?

PD7/U2TX is NMI. If you want to setup uart_echo using UART2, you need to add code that configures PD7 as UART. See related posts below.

http://e2e.ti.com/support/microcontrollers/stellaris_arm/f/471/p/63836/944394.aspx#944394

-kel

0 cb1_mobile over 11 years ago in reply to Markel Robregado

Guru 117855 points

If we accept friend Kel's read/verify of your code - might one of those Port_B pins be "cross-connected" to other GPIO - that board? Schematic will reveal. (if true - dispatch of 0-ohm smt R suggested...)

0 Chester Gillon over 11 years ago

Guru 92251 points

Erdem Varer said:
and here is my changed code to use uart1

I can see in uart_echo.c all the references to UART0 appear to have been changed to UART1. However, in the TivaWare_C_Series-1.0\examples\boards\ek-tm4c123gxl\uart_echo project there is also the startup_ccs.c source file which defines the interrupt handlers for each interrupt source.

In the startup_ccs.c in the TivaWare example the g_pfnVectors array only sets the interrupt handler for UART0, where UART1 is left with IntDefaultHandler (which just goes into an infinite loop). In the startup_ccs.c you also need to change from the following:

UARTIntHandler, // UART0 Rx and Tx
IntDefaultHandler, // UART1 Rx and Tx

To:

IntDefaultHandler, // UART0 Rx and Tx
UARTIntHandler, // UART1 Rx and Tx

Failure to do this means that when a UART1 interrupt occurs then the processor will get stuck in a while loop rather than handling the interrupt.

0 Erdem Varer over 11 years ago in reply to Chester Gillon

Prodigy 90 points

Thank you all for quick replies. i figured out the Chester Gillon's solution after finally certain about source of the problem which is interrupts. found startup_ccs.c file by chance and and changed as the way Chester said. now it works like a charm.

Hope this topic helps anyone who stuck with this.

Erdem

0 cb1_mobile over 11 years ago in reply to Markel Robregado

Guru 117855 points

Markel Robregado said:
Did you setup UARTIntHandler() at your startup file?

Appears that Kel earlier suggested that solution...

Arm-based microcontrollers

Arm-based microcontrollers forum

Stellaris - LM4F120H5QR - Changing/Using Different UART Modules - code based on stellarisware sample uart_echo.c