I am currently using several GPIOs, two SSI channels and two I2C channels in my project. Everything was going well until I added PB5 as a GPIO output for controlling an ADC CS pin. I have a scope on the pin at the booster pack J1-2, and the output is always high. Below is a snippet of the code that sets up the GPIOs. I have triple checked for pin assignment conflicts and can find none in the software. If I step through the while look at the bottom, the pin output never toggles. it just remains high. Any ideas? I feel like I'm missing something obvious, but I just can't get it working and I've spent way more time on it than I had hoped.
Thanks!
void GpioInit(void) {
// Enable the following GPIO pins:
// PE1 - Used for timer testing of the 4kHz loop. No tactical function.
// PD6 - Use for controlling the *CS line on the AZ ADC.
// PC7 - Use for controlling the *CS line on the EL ADC.
ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA); // Enable GPIO A
ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOB); // Enable GPIO B
ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOC); // Enable GPIO C
ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOD); // Enable GPIO D
ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOE); // Enable GPIO E
SysCtlDelay(500);
ROM_GPIOPinTypeGPIOOutput(GPIO_PORTA_BASE, GPIO_PIN_3 ); // Configure PA3 as a GPIO output.
ROM_GPIOPinTypeGPIOOutput(GPIO_PORTB_BASE, GPIO_PIN_5); // Configure PB5 as a GPIO output.
ROM_GPIOPinTypeGPIOOutput(GPIO_PORTC_BASE, GPIO_PIN_7 ); // Configure PC7 as a GPIO output.
ROM_GPIOPinTypeGPIOOutput(GPIO_PORTD_BASE, GPIO_PIN_6 ); // Configure PD6 as a GPIO output.
ROM_GPIOPinTypeGPIOOutput(GPIO_PORTE_BASE, GPIO_PIN_1 | GPIO_PIN_4 | GPIO_PIN_5); // Configure PE1/PE4/PE5 as a GPIO output.
ROM_GPIOPinTypeGPIOInput(GPIO_PORTD_BASE, GPIO_PIN_1);
ROM_GPIOPinTypeGPIOInput(GPIO_PORTD_BASE, GPIO_PIN_2);
ROM_SysCtlDelay(500); // Delay for a few clock ticks to allow the changes to apply before changing the state.
// Initialize the ADC *CS pins HIGH output. The *CS is active low.
// Use direct register writes (DMA) for GPIO control to minimize latency.
GPIO_PORTA_DATA_R |= GPIO_PIN_3;
GPIO_PORTB_DATA_R |= GPIO_PIN_5;
GPIO_PORTC_DATA_R |= GPIO_PIN_7;
GPIO_PORTD_DATA_R |= GPIO_PIN_6;
GPIO_PORTE_DATA_R |= GPIO_PIN_4;
GPIO_PORTE_DATA_R |= GPIO_PIN_5;
GPIO_PORTE_DATA_R &= ~GPIO_PIN_1;
while (1) {
GPIO_PORTB_DATA_R &= ~GPIO_PIN_5;
GPIO_PORTB_DATA_R |= GPIO_PIN_5;
}
}
