Scrolling LED Display using Tiva C series

Hi,

In the absence of some electrical diagrams to understand your project, several "urgent" observations:

a) the variables alpha_cnt and char_cnt are tested against some weird values, i.e. 156 and 14000 - 

b) the variable count is initialised with 1 so the for loop executes only once and the programs exit main, going into landscape. Not sure about SPI use, may be wrong, since you double use the SSIFSS pins: you configure them as SSIFSS (automatically managed by the micro) and then manage manually.

Petrei

Hi Petrei,

                   Unfortunately I had posted the wrong source code, here I am attaching the code that I had already checked. About the values 156 and 14000 are used for alphabet counting and speed adjustment. If the value 14000 is increased, the speed of scrolling will reduces

#include <stdint.h>
#include <stdbool.h>
#include "inc/hw_memmap.h"
#include "inc/hw_ssi.h"
#include "inc/hw_types.h"
#include "driverlib/ssi.h"
#include "driverlib/gpio.h"
#include "driverlib/uart.h"
#include "driverlib/pin_map.h"
#include "driverlib/sysctl.h"
#include "utils/uartstdio.h"
#define NUM_SSI_DATA 256
char ALPHABETS[NUM_SSI_DATA] =
                            { 0x7F, 0x88, 0x88, 0x88, 0x7F, 0x00,   0x00, 0x00,
                                0xFF, 0x91, 0x91, 0x91, 0x6E, 0x00, 0x00, 0x00,
                                0x7E, 0x81, 0x81, 0x81, 0x42, 0x00, 0x00, 0x00,
                                0xFF, 0x81, 0x81, 0x42, 0x3C, 0x00, 0x00, 0x00,
                                0xFF, 0x91, 0x91, 0x91, 0x81, 0x00, 0x00, 0x00,
                                0xFF, 0x90, 0x90, 0x90, 0x80, 0x00, 0x00, 0x00,
                                0x7E, 0x81, 0x89, 0x89, 0x4E, 0x00, 0x00, 0x00,
                                0xFF, 0x10, 0x10, 0x10, 0xFF, 0x00, 0x00, 0x00,
                                0x81, 0x81, 0xFF, 0x81, 0x81, 0x00, 0x00, 0x00,
                                0x06, 0x01, 0x01, 0x01, 0xFE, 0x00, 0x00, 0x00,
                                0xFF, 0x18, 0x24, 0x42, 0x81, 0x00, 0x00, 0x00,
                                0xFF, 0x01, 0x01, 0x01, 0x01, 0x00, 0x00, 0x00,
                                0xFF, 0x40, 0x30, 0x40, 0xFF, 0x00, 0x00, 0x00,
                                0xFF, 0x40, 0x30, 0x08, 0xFF, 0x00, 0x00, 0x00,
                                0x7E, 0x81, 0x81, 0x81, 0x7E, 0x00, 0x00, 0x00,
                                0xFF, 0x88, 0x88, 0x88, 0x70, 0x00, 0x00, 0x00,
                                0x7E, 0x81, 0x85, 0x82, 0x7D, 0x00, 0x00, 0x00,
                                0xFF, 0x88, 0x8C, 0x8A, 0x71, 0x00, 0x00, 0x00,
                                0x61, 0x91, 0x91, 0x91, 0x8E, 0x00, 0x00, 0x00,
                                0x80, 0x80, 0xFF, 0x80, 0x80, 0x00, 0x00, 0x00,
                                0xFE, 0x01, 0x01, 0x01, 0xFE, 0x00, 0x00, 0x00,
                                0xF0, 0x0C, 0x03, 0x0C, 0xF0, 0x00, 0x00, 0x00,
                                0xFF, 0x02, 0x0C, 0x02, 0xFF, 0x00, 0x00, 0x00,
                                0xC3, 0x24, 0x18, 0x24, 0xC3, 0x00, 0x00, 0x00,
                                0xE0, 0x10, 0x0F, 0x10, 0xE0, 0x00, 0x00, 0x00,
                                0x83, 0x85, 0x99, 0xA1, 0xC1, 0x00, 0x00, 0x00};
                                
const char col_arr1[] = {0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80};  
//*****************************************************************************
//
// Configure the UART and its pins.  This must be called before UARTprintf().
//
//*****************************************************************************
/*void
ConfigureUART(void)
{
    //
    // Enable the GPIO Peripheral used by the UART.
    //
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);
    //
    // Enable UART0
    //
    SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0);
    //
    // Configure GPIO Pins for UART mode.
    //
    GPIOPinConfigure(GPIO_PA0_U0RX);
    GPIOPinConfigure(GPIO_PA1_U0TX);
    GPIOPinTypeUART(GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_1);
    //
    // Use the internal 16MHz oscillator as the UART clock source.
    //
    UARTClockSourceSet(UART0_BASE, UART_CLOCK_PIOSC);
    //
    // Initialize the UART for console I/O.
    //
    UARTStdioConfig(0, 9600, 16000000);
}
*/
    
    uint8_t ui32tx_cnt;
    uint8_t nxt_alpha = 0;
    uint32_t ui32tx_data;
    uint32_t alpha_cnt, char_cnt;
    uint8_t column;
    uint8_t bit_cnt = 0;
    uint32_t count = 1;
    uint32_t col_cnt = 0;
    //uint8_t col_inc   =   0;
int main(void)
{
    //bool col_inc  =   0;
    
    
    SysCtlClockSet(SYSCTL_SYSDIV_1 | SYSCTL_USE_PLL | SYSCTL_OSC_MAIN | SYSCTL_XTAL_16MHZ);
    SysCtlPeripheralEnable(SYSCTL_PERIPH_SSI0);
    SysCtlPeripheralEnable(SYSCTL_PERIPH_SSI2);
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOB);
    GPIOPinConfigure(GPIO_PA2_SSI0CLK);
    GPIOPinConfigure(GPIO_PA3_SSI0FSS);
    GPIOPinConfigure(GPIO_PA5_SSI0TX);
    GPIOPinConfigure(GPIO_PB4_SSI2CLK);
    GPIOPinConfigure(GPIO_PB5_SSI2FSS);
    GPIOPinConfigure(GPIO_PB7_SSI2TX);
    
    GPIOPinTypeSSI(GPIO_PORTA_BASE,GPIO_PIN_5|GPIO_PIN_3|GPIO_PIN_2);
    GPIOPinTypeSSI(GPIO_PORTB_BASE,GPIO_PIN_4|GPIO_PIN_5|GPIO_PIN_7);
   //ConfigureUART();
    //UARTprintf("*********8X8 LED DOT MATRIX*********\n");
    SysCtlDelay(10000);
    
    SSIConfigSetExpClk(SSI0_BASE, SysCtlClockGet(), SSI_FRF_MOTO_MODE_0, SSI_MODE_MASTER, 100000, 8);
    SSIConfigSetExpClk(SSI2_BASE, SysCtlClockGet(), SSI_FRF_MOTO_MODE_0, SSI_MODE_MASTER, 100000, 8);
    SSIEnable(SSI0_BASE);
    SSIEnable(SSI2_BASE);
    //while(1){
//////////////////////////////////////////////////////////////////////////////////////////
////          Just printing some english alphabets as in the ALPHABETS array     ////////
////////////////////////////////////////////////////////////////////////////////////////
    
for(alpha_cnt = 0;alpha_cnt < 156;alpha_cnt++){
///////////////////////////////////////////////////////////////////////////////////////
/////  Char_cnt determines the speed of the scrolling            /////////////////////
/////////////////////////////////////////////////////////////////////////////////////
 
        for(char_cnt = 0;char_cnt < 14000;char_cnt++){
////////////////////////////////////////////////////////////////////////////////////
///////  ui32tx_cnt determines the scrolling and displaying ///////////////////////
//////////////////////////////////////////////////////////////////////////////////
 
            for(ui32tx_cnt = 0;ui32tx_cnt < count;ui32tx_cnt++)
            {
            ALPHABETS[ui32tx_cnt] = ALPHABETS[ui32tx_cnt + nxt_alpha];
            ui32tx_data = ALPHABETS[ui32tx_cnt];
            GPIOPinWrite(GPIO_PORTA_BASE, GPIO_PIN_3, 0);
            GPIOPinWrite(GPIO_PORTB_BASE, GPIO_PIN_5, 0);
            SSIDataPutNonBlocking(SSI2_BASE, (~ui32tx_data));
            column = col_arr1[ui32tx_cnt];
            SSIDataPutNonBlocking(SSI0_BASE, column);
                
            GPIOPinWrite(GPIO_PORTA_BASE, GPIO_PIN_3, GPIO_PIN_3); 
            GPIOPinWrite(GPIO_PORTB_BASE, GPIO_PIN_5, GPIO_PIN_5);
            //UARTprintf("%x\t",ui32tx_data);
            //UARTCharPut(UART0_BASE, column); 
            }                                                                              
            //UARTprintf("\n");
    }                                                                              
        //col_cnt++;
    if(count == 8){
        count = 1;}
        else{
        count++;
        }
        bit_cnt++;
        if(bit_cnt > 7){
        nxt_alpha++;
        }
    }                                                                                  
        //column = 0;
        //col_inc = 0;
    //}
}

Regards

Nithin

Hi,

I think is still the old code, no changes. Please check braces matching in main function. I cannot see a while(1) block, so your code will exit to landscape (out of main), suppose it crashes. Am I right?

Petrei