User Manual

Reference

C++ methods are shown in red.

C/C++ functions are shown in green.

static unsigned char OrangutanPulseIn::start(const unsigned char pulse_pins[], unsigned char

num_pins)

unsigned char pulse_in_start(const unsigned char pulse_pins[], unsigned char num_pins)

Configures the AVR’s pin-change interrupts to measure pulses on the specified pins. The num_pins

parameter should be the length of the pulse_pins array. A nonzero return value indicates that the needed

memory could not be allocated.

The pulse_pins parameter should be the RAM address of an array of AVR I/O pin numbers defined using

the IO_* keywords provided by the library (e.g. IO_D1 for a pulse input on pin PD1). This function does

not configure the pulse_pins as digital inputs, which makes it possible to measure pulses on pins being

used as outputs. AVR I/O pins default to digital inputs with the internal pull-up disabled after a reset or

power-up.

Example

// configure pins PD0 and PD1 as pulse input channels

pulse_in_start((unsigned char[]) {IO_D0, IO_D1}, 2);

// configure pins PD0 and PD1 as pulse input channels

OrangutanPulseIn::start((unsigned char[]) {IO_D0, IO_D1}, 2);

static void OrangutanPulseIn::stop()

void pulse_in_stop()

Disables all pin-change interrupts and frees up the memory that was dynamically allocated by the

pulse_in_start() function. This can be useful if you no longer want state changes of your pulse-measuring

channels to interrupt program execution.

static void OrangutanPulseIn::getPulseInfo(unsigned char channel, struct PulseInputStruct*

pulse_info)

void get_pulse_info(unsigned char channel, struct PulseInputStruct* pulse_info)

This function uses the pulse_info pointer to return a snapshot of the pulse state for the specified channel,

channel. After get_pulse_info() returns, pulse_info will point to a copy of the PulseInputStruct that is

automatically maintained by the the pin-change ISR for the specified channel. Additionally, after the

copy is made, this function clears the newPulse flags (both high pulse and low pulse) in the original,

ISR-maintained PulseInputStruct. Since pulse_info is a copy, the pin-change ISR will never change the

pulse_info data. Working with pulse_info is especially useful if you need to be sure that all of your puse

data for a single channel came from the same instant in time, since pin-change interrupts are disabled

while the ISR-maintained PulseInputStruct is being copied to pulse_info.

The argument channel should be a number from 0 to one less than the total number of channels used

(num_pins-1); the channel acts as an index to the pulse_pins array supplied to the pulse_in_start()

function.

See the “Pulse Information Variables” section at the top of this page for documentation of the members

of the PulseInputStruct pulse_info, and see the pulsein1 sample program for an example of how to use

get_pulse_info() as the basis of your pulse-reading code.

8. Orangutan Pulse/PWM Inputs Page 32 of 65