10 years, 5 months ago.

PwmOut, HighPWM, and FastPWM not working

I'm writing a fairly complex program (by my standards at least), and I need to use a PWM output to provide clocking to a device. The clock has to be 12MHz so I have to use the HighPWM or FastPWM libraries to get that kind of frequency. The issue I'm having is that the PWM works in a blank program, but doesn't work in mine.

Here are my subsystem delcarations:

DigitalOut led1(LED1);
HighPWM spi_clk(p26);

//Timer t;

SPI spi(p5, p6, p7);
DigitalOut cs(p8);
 
DigitalIn i_d(p15);
DigitalIn i_clk(p16);
//InterruptIn i_int_clk(p16);

DigitalOut o_d(p17); 
DigitalOut o_clk(p18);
//InterruptIn o_int_clk(p18);

USBKeyboard keyboard;

As you can see, I've tried enabling and disabling declarations, changing the order, so on and so forth, but that hasn't changed anything. Except, when I put the PWM declaration first, the pin goes low. If I put it in the middle or last, the PWM doesn't activate at all and the voltage stays around 2.3V.

In my main method, I have:

int main() {

    spi_clk.period_ticks(8);
    spi_clk.pulsewidth_ticks(4);
    
    while(1) {
    }
}

I'm at a loss here. If I just use the PWM in a blank program, it runs smoothly but it refuses to run in my code. I didn't put the entire code here because it's about 600 lines and nobody wants to read through all that. Is there a clash of subsystems somewhere that I don't know about? I thought that maybe the SPI clock was causing issues, but I tried all 6 PWM channels and got the exact same result. I also tried the other PWM libraries but all had the same result.

EDIT: I've found out that it's the USBKeyboard library that's causing the issue. I can't seem to find a way for them to hold hands and be friendly. Do you guys have any suggestions?