TM4C129ENCZAD: Telnet and GPIO Performance

JAOverstreet

I have a TM4C129ENCZAD microcontroller I am using to control GPIO through Telnet. I have modified the shell environment to control GPIO outputs through telnet via some simple commands.

A GPIO in is turned off with the following code,

static void open(char *str)
{
    if (str[1] == '0'){
        ROM_GPIOPinWrite(GPIO_PORTE_BASE, GPIO_PIN_6, 0);
        shell_output("<0>","");
    }
    if (str[1] == '1'){
        ROM_GPIOPinWrite(GPIO_PORTB_BASE, GPIO_PIN_5, 0);
        shell_output("<0>","");
    }
    if (str[1] == '2'){
        ROM_GPIOPinWrite(GPIO_PORTE_BASE, GPIO_PIN_4, 0);
        shell_output("<0>","");
    }
    if (str[1] == '3'){
        ROM_GPIOPinWrite(GPIO_PORTD_BASE, GPIO_PIN_4, 0);
        shell_output("<0>","");
    }
    if (str[1] == '4'){
        ROM_GPIOPinWrite(GPIO_PORTD_BASE, GPIO_PIN_6, 0);
        shell_output("<0>","");
    }
    if (str[1] == '5'){
        ROM_GPIOPinWrite(GPIO_PORTD_BASE, GPIO_PIN_1, 0);
        shell_output("<0>","");
    }
    if (str[1] == '6'){
        ROM_GPIOPinWrite(GPIO_PORTD_BASE, GPIO_PIN_3, 0);
        shell_output("<0>","");
    }
    if (str[1] == '7'){
        ROM_GPIOPinWrite(GPIO_PORTQ_BASE, GPIO_PIN_1, 0);
        shell_output("<0>","");
    }
    if (str[1] == '8'){
        ROM_GPIOPinWrite(GPIO_PORTB_BASE, GPIO_PIN_7, 0);
        shell_output("<0>","");
    }
    if (str[1] == '9'){
        ROM_GPIOPinWrite(GPIO_PORTE_BASE, GPIO_PIN_2, 0);
        shell_output("<0>","");
    }
    if (str[1] == 'A'){
        ROM_GPIOPinWrite(GPIO_PORTE_BASE, GPIO_PIN_1, 0);
        shell_output("<0>","");
    }
    if (str[1] == 'B'){
        ROM_GPIOPinWrite(GPIO_PORTK_BASE, GPIO_PIN_0, 0);
        shell_output("<0>","");
    }
    if (str[1] == 'C'){
        ROM_GPIOPinWrite(GPIO_PORTK_BASE, GPIO_PIN_2, 0);
        shell_output("<0>","");
    }
    if (str[1] == 'D'){
        ROM_GPIOPinWrite(GPIO_PORTC_BASE, GPIO_PIN_6, 0);
        shell_output("<0>","");
    }
    if (str[1] == 'E'){
        ROM_GPIOPinWrite(GPIO_PORTC_BASE, GPIO_PIN_5, 0);
        shell_output("<0>","");
    }
    if (str[1] == 'F'){
        ROM_GPIOPinWrite(GPIO_PORTJ_BASE, GPIO_PIN_6, 0);
        shell_output("<0>","");
    }
    if (str[1] == 'G'){
        ROM_GPIOPinWrite(GPIO_PORTR_BASE, GPIO_PIN_5, 0);
        shell_output("<0>","");
    }
    if (str[1] == 'H'){
        ROM_GPIOPinWrite(GPIO_PORTH_BASE, GPIO_PIN_2, 0);
        shell_output("<0>","");
    }
    if (str[1] == 'I'){
        ROM_GPIOPinWrite(GPIO_PORTH_BASE, GPIO_PIN_3, 0);
        shell_output("<0>","");
    }
    if (str[1] == 'J'){
        ROM_GPIOPinWrite(GPIO_PORTH_BASE, GPIO_PIN_6, 0);
        shell_output("<0>","");
    }
}

A GPIO pin is turned on with the following code,

static void close(char *str)
{
    if (str[1] == '0'){
        ROM_GPIOPinWrite(GPIO_PORTE_BASE, GPIO_PIN_6, GPIO_PIN_6);
        shell_output("<1>","");
    }
    if (str[1] == '1'){
        ROM_GPIOPinWrite(GPIO_PORTB_BASE, GPIO_PIN_5, GPIO_PIN_5);
        shell_output("<1>","");
    }
    if (str[1] == '2'){
        ROM_GPIOPinWrite(GPIO_PORTE_BASE, GPIO_PIN_4, GPIO_PIN_4);
        shell_output("<1>","");
    }
    if (str[1] == '3'){
        ROM_GPIOPinWrite(GPIO_PORTD_BASE, GPIO_PIN_4, GPIO_PIN_4);
        shell_output("<1>","");
    }
    if (str[1] == '4'){
        ROM_GPIOPinWrite(GPIO_PORTD_BASE, GPIO_PIN_6, GPIO_PIN_6);
        shell_output("<1>","");
    }
    if (str[1] == '5'){
        ROM_GPIOPinWrite(GPIO_PORTD_BASE, GPIO_PIN_1, GPIO_PIN_1);
        shell_output("<1>","");
    }
    if (str[1] == '6'){
        ROM_GPIOPinWrite(GPIO_PORTD_BASE, GPIO_PIN_3, GPIO_PIN_3);
        shell_output("<1>","");
    }
    if (str[1] == '7'){
        ROM_GPIOPinWrite(GPIO_PORTQ_BASE, GPIO_PIN_1, GPIO_PIN_1);
        shell_output("<1>","");
    }
    if (str[1] == '8'){
        ROM_GPIOPinWrite(GPIO_PORTB_BASE, GPIO_PIN_7, GPIO_PIN_7);
        shell_output("<1>","");
    }
    if (str[1] == '9'){
        ROM_GPIOPinWrite(GPIO_PORTE_BASE, GPIO_PIN_2, GPIO_PIN_2);
        shell_output("<1>","");
    }
    if (str[1] == 'A'){
        ROM_GPIOPinWrite(GPIO_PORTE_BASE, GPIO_PIN_1, GPIO_PIN_1);
        shell_output("<1>","");
    }
    if (str[1] == 'B'){
        ROM_GPIOPinWrite(GPIO_PORTK_BASE, GPIO_PIN_0, GPIO_PIN_0);
        shell_output("<1>","");
    }
    if (str[1] == 'C'){
        ROM_GPIOPinWrite(GPIO_PORTK_BASE, GPIO_PIN_2, GPIO_PIN_2);
        shell_output("<1>","");
    }
    if (str[1] == 'D'){
        ROM_GPIOPinWrite(GPIO_PORTC_BASE, GPIO_PIN_6, GPIO_PIN_6);
        shell_output("<1>","");
    }
    if (str[1] == 'E'){
        ROM_GPIOPinWrite(GPIO_PORTC_BASE, GPIO_PIN_5, GPIO_PIN_5);
        shell_output("<1>","");
    }
    if (str[1] == 'F'){
        ROM_GPIOPinWrite(GPIO_PORTJ_BASE, GPIO_PIN_6, GPIO_PIN_6);
        shell_output("<1>","");
    }
    if (str[1] == 'G'){
        ROM_GPIOPinWrite(GPIO_PORTR_BASE, GPIO_PIN_5, GPIO_PIN_5);
        shell_output("<1>","");
    }
    if (str[1] == 'H'){
        ROM_GPIOPinWrite(GPIO_PORTH_BASE, GPIO_PIN_2, GPIO_PIN_2);
        shell_output("<1>","");
    }
    if (str[1] == 'I'){
        ROM_GPIOPinWrite(GPIO_PORTH_BASE, GPIO_PIN_3, GPIO_PIN_3);
        shell_output("<1>","");
    }
    if (str[1] == 'J'){
        ROM_GPIOPinWrite(GPIO_PORTH_BASE, GPIO_PIN_6, GPIO_PIN_6);
        shell_output("<1>","");
    }
}

A GPIO pin is checked with the following code,

static void status(char *str)
{
    if (str[1] == '0')
    {
        if (ROM_GPIOPinRead(GPIO_PORTE_BASE, GPIO_PIN_6))
        {
            shell_output("<1>","");
        }
        else
        {
            shell_output("<0>","");
        }
    }
    if (str[1] == '1')
    {
        if (ROM_GPIOPinRead(GPIO_PORTB_BASE, GPIO_PIN_5))
        {
            shell_output("<1>","");
        }
        else
        {
            shell_output("<0>","");
        }
    }
    if (str[1] == '2')
    {
        if (ROM_GPIOPinRead(GPIO_PORTE_BASE, GPIO_PIN_4))
        {
            shell_output("<1>","");
        }
        else
        {
            shell_output("<0>","");
        }
    }
    if (str[1] == '3')
    {
        if (ROM_GPIOPinRead(GPIO_PORTD_BASE, GPIO_PIN_4))
        {
            shell_output("<1>","");
        }
        else
        {
            shell_output("<0>","");
        }
    }
    if (str[1] == '4')
    {
        if (ROM_GPIOPinRead(GPIO_PORTD_BASE, GPIO_PIN_6))
        {
            shell_output("<1>","");
        }
        else
        {
            shell_output("<0>","");
        }
    }
    if (str[1] == '5')
    {
        if (ROM_GPIOPinRead(GPIO_PORTD_BASE, GPIO_PIN_1))
        {
            shell_output("<1>","");
        }
        else
        {
            shell_output("<0>","");
        }
    }
    if (str[1] == '6')
    {
        if (ROM_GPIOPinRead(GPIO_PORTD_BASE, GPIO_PIN_3))
        {
            shell_output("<1>","");
        }
        else
        {
            shell_output("<0>","");
        }
    }
    if (str[1] == '7')
    {
        if (ROM_GPIOPinRead(GPIO_PORTQ_BASE, GPIO_PIN_1))
        {
            shell_output("<1>","");
        }
        else
        {
            shell_output("<0>","");
        }
    }
    if (str[1] == '8')
    {
        if (ROM_GPIOPinRead(GPIO_PORTB_BASE, GPIO_PIN_7))
        {
            shell_output("<1>","");
        }
        else
        {
            shell_output("<0>","");
        }
    }
    if (str[1] == '9')
    {
        if (ROM_GPIOPinRead(GPIO_PORTE_BASE, GPIO_PIN_2))
        {
            shell_output("<1>","");
        }
        else
        {
            shell_output("<0>","");
        }
    }
    if (str[1] == 'A')
    {
        if (ROM_GPIOPinRead(GPIO_PORTE_BASE, GPIO_PIN_1))
        {
            shell_output("<1>","");
        }
        else
        {
            shell_output("<0>","");
        }
    }
    if (str[1] == 'B')
    {
        if (ROM_GPIOPinRead(GPIO_PORTK_BASE, GPIO_PIN_0))
        {
            shell_output("<1>","");
        }
        else
        {
            shell_output("<0>","");
        }
    }
    if (str[1] == 'C')
    {
        if (ROM_GPIOPinRead(GPIO_PORTK_BASE, GPIO_PIN_2))
        {
            shell_output("<1>","");
        }
        else
        {
            shell_output("<0>","");
        }
    }
    if (str[1] == 'D')
    {
        if (ROM_GPIOPinRead(GPIO_PORTC_BASE, GPIO_PIN_6))
        {
            shell_output("<1>","");
        }
        else
        {
            shell_output("<0>","");
        }
    }
    if (str[1] == 'E')
    {
        if (ROM_GPIOPinRead(GPIO_PORTC_BASE, GPIO_PIN_5))
        {
            shell_output("<1>","");
        }
        else
        {
            shell_output("<0>","");
        }
    }
    if (str[1] == 'F')
    {
        if (ROM_GPIOPinRead(GPIO_PORTJ_BASE, GPIO_PIN_6))
        {
            shell_output("<1>","");
        }
        else
        {
            shell_output("<0>","");
        }
    }
    if (str[1] == 'G')
    {
        if (ROM_GPIOPinRead(GPIO_PORTR_BASE, GPIO_PIN_5))
        {
            shell_output("<1>","");
        }
        else
        {
            shell_output("<0>","");
        }
    }
    if (str[1] == 'H')
    {
        if (ROM_GPIOPinRead(GPIO_PORTH_BASE, GPIO_PIN_2))
        {
            shell_output("<1>","");
        }
        else
        {
            shell_output("<0>","");
        }
    }
    if (str[1] == 'I')
    {
        if (ROM_GPIOPinRead(GPIO_PORTH_BASE, GPIO_PIN_3))
        {
            shell_output("<1>","");
        }
        else
        {
            shell_output("<0>","");
        }
    }
    if (str[1] == 'J')
    {
        if (ROM_GPIOPinRead(GPIO_PORTH_BASE, GPIO_PIN_6))
        {
            shell_output("<1>","");
        }
        else
        {
            shell_output("<0>","");
        }
    }
}

I need to switch GPIO pins on/off as quickly as possible, but it takes about 750 milliseconds to switch.

In the computer I am sending the telnet commands to turn on and off gpio pins via a C# program.

Sending the open or close command without verifying the microcontroller switched correctly will prevent some GPIO pins from turning off/on correctly.

do
{
    string close_result1 = cdf_muxes[card].close(channel);
    string close_result2 = cdf_muxes[card + 1].close(channel);
    if (close_result1.Contains("1")) cr1 = true; else cr1 = false;
    if (close_result2.Contains("1")) cr2 = true; else cr2 = false;
} while (!(cr1 == true & cr2 == true));

bool or1 = false;
bool or2 = false;
do
{
    string open_result1 = cdf_muxes[card].open(channel);
    string open_result2 = cdf_muxes[card + 1].open(channel);
    if (open_result1.Contains("0")) or1 = true; else or1 = false;
    if (open_result2.Contains("0")) or2 = true; else or2 = false;

} while (!(or1 == true & or2 == true));

Does anyone have any suggestions on how to decrease the amount of time it takes to turn a GPIO pin on/off?

Thanks,

Allan

over 3 years ago

0 Ralph Jacobi over 3 years ago

TI__Guru*** 135355 points

Hello Allan,

750 milliseconds seems like a lot of time, I am not sure what the bottlenecks would be specifically with this kind of implementation as I am not familiar with Telnet. From an MCU code standpoint there shouldn't be that slow processing through I would say you'd be better off using a switch case statement rather than the ifs because from what I can tell each open/close it can only change 1 GPIO - so doing the list of ifs you have is a lot more checks than you need because you just need to go until you find the right GPIO and then exit out.

But that inefficiency wouldn't explain it taking close to a second so I suspect there is something going on with the way the Telnet protocol sends and receives that is delaying it further.

Best Regards,

0 Chester Gillon over 3 years ago

Guru 92251 points

JAOverstreet said:
I need to switch GPIO pins on/off as quickly as possible, but it takes about 750 milliseconds to switch.

In the computer I am sending the telnet commands to turn on and off gpio pins via a C# program.

In the computer has the C# program set the NoDelay Property on the socket?

If not, Nagle's algorithm might be the cause of the delays.

0 JAOverstreet over 3 years ago in reply to Chester Gillon

Intellectual 650 points

Chester,

The tcpSocket.NoDelay property has been set to true.

 public TelnetConnection(string Hostname, int Port, ref bool result)
        {
            try
            {
                tcpSocket = new TcpClient();
                tcpSocket.ReceiveTimeout = 1;
                tcpSocket.SendTimeout = 1;
                tcpSocket.NoDelay = true;

                tcpSocket.Connect(Hostname, Port);
                result = true;
            }
            catch (Exception ex)
            {
                Trace.WriteLine($"TelnetConnection Error: {ex.Message}");
                result = false;
            }
        }

Thanks,

Allan

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TM4C129ENCZAD: Telnet and GPIO Performance