MSP-EXP432P401R: Display_Handle access second UART Display

Hi Aaron,

Actually, the same Display_open() function can be used to open both displays, but it's not done using the second function parameter. I found the "display_MSP_EXP432P401R_tirtos_ccs" code example in TI Resource Explorer. In the 'display.c', you can see where two displays are opened: LCD and UART. They use the same function and parameters but are set equal to different structures, hLcd and hSerial.

/* Open both an available LCD display and an UART display.
 * Whether the open call is successful depends on what is present in the
 * Display_config[] array of the driver configuration file.
 */
Display_Handle hLcd = Display_open(Display_Type_LCD, &params);
Display_Handle hSerial = Display_open(Display_Type_UART, &params);

You could change this code to something like this.

Display_Handle hLcd1 = Display_open(Display_Type_LCD, &params);
Display_Handle hLcd2 = Display_open(Display_Type_LCD, &params);

For your code, you will also need to configure the displays (e.g. type, baud rate, etc.) by modifying the .syscfg file in SysConfig.

Hi James,
thank you very much for your answer. Maybe I should specify. I tried the proposed solution of yours beforehand:

Display_Params paramsDP;
Display_Params_init(&paramsDP);
paramsDP.lineClearMode = DISPLAY_CLEAR_BOTH;

Display_Handle hUARTXDS = Display_open(Display_Type_UART, &paramsDP);
Display_Handle hUARTXP = Display_open(Display_Type_UART, &paramsDP);

However "&params" doesn't work. When adding the second Display_Open function, even the first display doesn't work anymore.

So I imagine the problem is with the second parameter in the "Display_open" function.

All the best and thanks for trying to help me.

I think this might be also a problem:

 /*
 * @note        Only one display is opened. If the type matches more than one,
 *              only the first one found in the Display_config array is opened.
 */

As stated in display.h

Due to debugging I found out that the problem seems to be with the Display_print - function. The program is running proberly until this function is reached.

This are the Variables BEFORE the Display_print - function is called:

The program stays in an endless loop, after calling the funtion. Even a line after that isn't reached.

This would be the code in ti_drivers_config.c

/*
 *  ============================= Display =============================
 */

#include <ti/display/Display.h>
#include <ti/display/DisplayUart.h>

#define Display_UARTBUFFERSIZE 1024
static char displayUARTBuffer[Display_UARTBUFFERSIZE];

DisplayUart_Object displayUartObject;

const DisplayUart_HWAttrs displayUartHWAttrs = {
    .uartIdx      = XDS110_UART,
    .baudRate     = 115200,
    .mutexTimeout = (unsigned int)(-1),
    .strBuf       = displayUARTBuffer,
    .strBufLen    = Display_UARTBUFFERSIZE
};

const Display_Config Display_config[] = {
    /* XPort_Display */
    {
        .fxnTablePtr = &DisplayUartMin_fxnTable,
        .object      = &displayUartObject,
        .hwAttrs     = &displayUartHWAttrs
    },
    /* XDS110_Display */
    {
        .fxnTablePtr = &DisplayUartMin_fxnTable,
        .object      = &displayUartObject,
        .hwAttrs     = &displayUartHWAttrs
    },
};

const uint_least8_t Display_count = 2;

I'm kind of wondering why there is no statement for the displays in the header file, is there an explanation for that?

Thanks for sharing the detailed updates. I'm starting to suspect that the latest issue may be caused by the XDS110_UART hardware selection. For both Display instances in SysConfig, can you try changing "Use Hardware" to "none"? Otherwise, both displays may be trying to use the same backchannel UART. You'll still need to call Display_open() for each display.

Thanks for helping, again. I created a new syscfg - file, since I want to port it later on to a board with a little different pin layout. Because of that I don't have the possibility to choose between "Use Hardware" and "none", I haven't implemented "Hardware" in the Sys Config.

This is my current config:

Thank you so much for helping! :)

For now, you may want to use the default config file, just in case there's an issue with the custom version. I think what's important is making sure the UART port/pin isn't the same between the two display instances.