Keith Mitchell

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9 years, 2 months ago.

"Siren Lights" when initializing I2C

I'm trying to use the PTB1-PTB0 I2C bus on the Hexiwear to read from the heart-rate sensor and the ambient light sensor.

However, when I try to initialize I2C with the correct pins, I get the blinking red siren light. If I try to initialize it with the I2C bus on PTC11-PTC10 I don't get the siren light.

Here is the code I'm trying to use:

Test code

#include "mbed.h"

#define maxim_sda PTB1
#define maxim_scl PTB0

DigitalOut led_green(PTD0);

I2C i2c(maxim_sda, maxim_scl);

int main() {
    while (1) {
        led_green =! led_green;
        wait(200);
    }
}

If I comment out the I2C line, or change it to the other available I2C bus the program works as expected.

Any ideas on whats wrong?

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