Pico4Drive Library

Introduction

This library has functions to handle the peripherals on the Pico4Drive development board. These include:

• motor drivers
• analog multiplexer
• power monitoring and control

To use the library, just download pico4drive.cc and pico4drive.h and add them to your project. Adjust the F_CPU constant in pico4drive.h, if needed.

Reference

void pico4drive_init(void)

Initialize the library. This sets up the PWM timers, configure the ADC and GPIO's to appropriate states.

void pico4drive_set_motor_pwm(int driver, float value)

Set the motor PWM level for one driver.

Parameter	Description
driver	one of the DRV_1, ..., DRV_4 constants
value	pmw level from -1.0 to 1.0. Positive values will make the A output (positive) voltage higher than the B output

uint16_t pico4drive_read_adc(int channel)

Read the analog value from one ofthe analog multiplexer input. Returns the ADC value in the range 0 .. 4095

Parameter	Description
channel	channel number 0..7

void pico4drive_poweroff(void)

Turns the board off. This can be used, for instance, to implement auto power off after a period of inactivity.

void pico4drive_update(void)

Update battery voltage and button state. The board updates this at roughly 50Hz, but this function can be called at a different rate. Calling it once every 600ms is enough to not lose events (using the press count variable), but it can be called at higher rates, e.g. 100Hz

The global variables updated after calling this function are:

Variable	Description
int battery_mV	board input voltage in mV
int on_button_state	current button state (1:pressed, 0:released)
uint32_t on_button_press_count	number of times the button has been pressed. If the update function is called unfrequently, looking at on_button_state may miss button press events, but this variable is always updated anyway