MATLAB: How to configure a pin on the 28335 eZdsp board to be an interrupt signal source in Target Support Package TC2 3.1 (R2008b)

gpiointTarget Support Package TC2

I would like to have an external device trigger an event on the 28335 eZdsp board via XINT1.

The TI manual indicates that the default pin for XINT1 is GPIO0. I put in a Hardware Interrupt block in my model to generate a function call triggered by XINT1. I expected to get an interrupt whenever I toggle GPIO0, but this does not happen.

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The Hardware Interrupt block allows you to generate a function call triggered by XINT1 (CPU number = 1, PIE number = 4). However, you would still need to select a pin (for example, GPIO0) to be the interrupt signal source of XINT1.

To do this, you can add a "System Initialize" block (from the Real-Time Workshop -> Custom Code library) to your model and add some custom code that selects GPIO0 as the interrupt source. The attached model includes a System Initialize block, which does this.

Related Solutions

MATLAB: How to configure a GPIO pin as an external interrupt in a Target Support Package

The attached model configures GPIO0 as external interrupt to trigger the blinking of LED. The custom code in the System Initialize block assigns GPIO0 as an input to trigger the XINT1 interrupt:

EALLOW;                                        
GpioCtrlRegs.GPAMUX1.bit.GPIO0 = 0;            
GpioIntRegs.GPIOXINT1SEL.bit.GPIOSEL = 0;      
EDIS;                                          
XIntruptRegs.XINT1CR.bit.ENABLE = 1;           
XIntruptRegs.XINT1CR.bit.POLARITY = 1;

The ISR toggles the LED based on a rising edge of GPIO00. Connect GPIO to 3V and GND in order to blink the LED.

MATLAB: Does the code reset when I set the function to be run using EPWM4_TZINT interrupt with the F2808 eZdsp board in Target Support Package TC2 3.1 (R2008b)

The system resets in Target Support Package TC2 3.1 (R2008b) because the Simulink scheduler timer ISR does not block and also clear pending same group interrupts (here the same scheduler ISR) until it finishes itself. So the higher priority EPWM TZ5 interrupt could preempt the base rate scheduler ISR before it ends, thus when this preemption ends, the pending base rate ISR could cause the scheduler to overrun and reset.

In Target Support Package TC2 3.2 (R2009a) this behavior does not occur since the GPIO 24 toggles forever when the EPWM4_TZINT interrupt is triggered.

For the R2008b release, use the following workaround to avoid the reset by manually editing the code as follows:

1. In the generated code MW_c28xx_csl.c, change the function TINT0_isr() to be the following:

interrupt void TINT0_isr(void)
{
volatile unsigned int PIEIER1_stack_save = PieCtrlRegs.PIEIER1.all;
PieCtrlRegs.PIEIER1.all &= ~64;      //disable group1 lower/equal priority interrupts
asm(" RPT #5 || NOP");               //wait 5 cycles
IFR &= ~1;                           //eventually disable lower/equal priority pending interrupts
PieCtrlRegs.PIEACK.all = 1;          //ACK to block other interrupts from the same group to fire
IER |= 1;
EINT;                                //global interrupt enable
rt_OneStep();
DINT;                                // disable global interrupts during context switch, CPU will enable global interrupts after exiting ISR
PieCtrlRegs.PIEIER1.all = PIEIER1_stack_save;//restore PIEIER register that was modified
}

2. In the xxx_main.c file, change rt_OneStep() to be as below:

Add following lines before the TZinterupt_EZDSP_step();

asm(" SETC INTM");
PieCtrlRegs.PIEIER1.all |= (1 << 6);
asm(" CLRC INTM");

Add the following lines after the TZinterupt_EZDSP_step();

asm(" SETC INTM");
PieCtrlRegs.PIEIER1.all &= ~(1 << 6); //disable group1 lower/equal priority interrupts
asm(" RPT #5 || NOP");
IFR &= 0xFFFE;
PieCtrlRegs.PIEACK.all = 0x1;  //ACK to block other interrupts from the same group to fire
asm(" CLRC INTM");

Build and run the code in the Code Composer Studio.

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Related Solutions

MATLAB: How to configure a GPIO pin as an external interrupt in a Target Support Package

MATLAB: Does the code reset when I set the function to be run using EPWM4_TZINT interrupt with the F2808 eZdsp board in Target Support Package TC2 3.1 (R2008b)

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