As the title says, I am working on setting up the UART1 with a non-standard baud rate. Specifically, I am looking to use the baud rate used in MIDI communication, which is 31250.
I've looked through the forums, and most questions are related to high-speed baud rates, which is not the case here. Everytime I try to set the Baud Rate, I enter in to the Fault ISR. I've been reading the datasheet, specifically 14.3.2 and believe I may need to change the UARTFBRD register. However, I am unsure of what value to use as I'm not sure how to properly use the equations.
My code can be seen below. Thanks!
//***************************************************************************** // // uart_echo.c - Example for reading data from and writing data to the UART in // an interrupt driven fashion. // // Copyright (c) 2012-2014 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 2.1.0.12573 of the EK-TM4C123GXL Firmware Package. // //***************************************************************************** #include <stdint.h> #include <stdbool.h> #include "inc/hw_ints.h" #include "inc/hw_memmap.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, uint32_t ui32Line) { } #endif //***************************************************************************** // // The UART interrupt handler. // //***************************************************************************** void UARTIntHandler(void) { uint32_t ui32Status; // // Get the interrrupt status. // ui32Status = ROM_UARTIntStatus(UART0_BASE, true); // // Clear the asserted interrupts. // ROM_UARTIntClear(UART0_BASE, ui32Status); // // 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 uint8_t *pui8Buffer, uint32_t ui32Count) { // // Loop while there are more characters to send. // while(ui32Count--) { // // Write the next character to the UART. // ROM_UARTCharPutNonBlocking(UART0_BASE, *pui8Buffer++); } } //***************************************************************************** // // 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_UART1); ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOB); // // Enable processor interrupts. // ROM_IntMasterEnable(); // // Set GPIO A0 and A1 as UART pins. // AJR: Change to PB0/PB1 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. // AJR: Changed to 32500 ROM_UARTConfigSetExpClk(UART0_BASE, ROM_SysCtlClockGet(), 31250, (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((uint8_t *)"\033[2JEnter text: ", 16); // // Loop forever echoing data through the UART. // while(1) { } }