This module contains low level functions for timer interaction. More...

Files
file	attiny13a_timer.h
	Header file for attiny13a timers.

Macros
#define	IC_PIN PIN4
	Pin used for input capture.

Enumerations

Functions
mcu_error	TIMER_setupCount (timer_main timerNumber, uint16_t frequency, void(*handler)(void))
	Initialize given timer for standard count with interrupt trigging the function handler on timeout. More...

mcu_error	TIMER_setupIC (timer_main timerNumber, timer_channel timerChannel)
	Initialize given timer for input capture. More...

mcu_error	TIMER_setupPWM (timer_main timerNumber, timer_channel timerChannel, uint16_t frequency, uint8_t duty)
	Initialize given timer for PWM mode. More...

mcu_error	TIMER_setupPulse (timer_main timerNumber, timer_channel timerChannel, uint16_t frequency, uint16_t pulse)
	Initialize given timer for Pulse mode. More...

mcu_error	TIMER_setPeriod (timer_main timerNumber, uint32_t period)
	Set the period for the timer. (in microseconds) More...

mcu_error	TIMER_setFrequency (timer_main timerNumber, uint16_t frequency)
	Set the frequency for the timer. (in hertz) More...

mcu_error	TIMER_setDuty (timer_main timerNumber, timer_channel channel, uint8_t duty)
	Set the duty cycle for the waveform (PWM only, 0 - 100%). More...

mcu_error	TIMER_setPulse (timer_main timerNumber, timer_channel channel, uint16_t pulse)
	Set the pulse width for the output. (in milliseconds) More...

uint8_t	TIMER_getCount (timer_main timerNumber)
	Get the current value of a running timer. More...

mcu_error	TIMER_setCount (timer_main timerNumber, uint8_t count)
	Set the current value of a running timer. More...

uint16_t	TIMER_getIC (timer_main timerNumber, timer_channel channel)
	Get the last input capture time from a channel of a timer. More...

mcu_error	TIMER_enableISR (timer_main timerNumber, void(*handler)(void))
	Set the ISR target for timeout. More...

mcu_error	TIMER_disableISR (timer_main timerNumber)
	Disable the timeout IRQ. More...

mcu_error	TIMER_pause (timer_main timerNumber)
	Pause an already running timer. More...

mcu_error	TIMER_resume (timer_main timerNumber)
	Resume a paused timer. More...

Detailed Description

This module contains low level functions for timer interaction.

The ATTINY13A has a single 8 bit timer with two output channels with output channels mapped to:

Timer 0
- Channel 1 - PORT B, PIN 0
- Channel 2 - PORT B, PIN 1

The low width of the timer means there are frequency and resolution restrictions. See the given function descriptions.

Note

Some features of this module are disabled by default to save space in flash ROM. The follow should be done to enable these features:

To use TIMER_setupCount(), TIMER_setPeriod(), TIMER_setFrequency(), TIMER_enableISR() or TIMER_disableISR() the TIMER_ISR flag needs to be uncommented in the Makefile.
To use TIMER_setupIC() or TIMER_getIC() TIMER_IC flag needs to be uncommented in the Makefile.

Many of the functions in the module have unused parameters. These parameters are kept in place for compatability with other MCUs.

Warning: Timer input capture and external interrupts (GPIO_ISREnable()) cannot both be used in the same application. Input caputre relies on external interrupt generation for triggers.

Author: Stuart Ianna

Version: 0.1

Date: October 2018

Copyright: GNU GPLv3

Bug:: None

Todo:

Compilers

avr-gcc V4.9.2

Working example

#include <stm32f103cb_core.h>
#include <coms128.h>
void up(void);
volatile uint8_t flag;
int main(void){
    //Clock setup
    CLOCK_setSpeed(CLOCK_EX_8_OUT_72);
    //Serial setup
    USART_setup(USART_2);
    USART_setBaud(USART_2,USART_BAUD_115200);
    COMS(USART_2);
    //Setup timer 3 to call function "up" at 10Hz
    TIMER_setupCount(TIMER_3,20,&up);               //Period = 50000 -> Resolution = 1us
    //Setup timer 1 for pulse width output at 1000Hz
    TIMER_setupPulse(TIMER_1,CHANNEL_1,1000,400);   //400us pulse
    TIMER_setupPulse(TIMER_1,CHANNEL_2,1000,50);    //50us pulse
    //Setup timer 2 for PWM at 10kHz
    TIMER_setupPWM(TIMER_2,CHANNEL_1,10000,50);     //50% duty cycle
    //Setup timer four for input capture
    TIMER_setupIC(TIMER_4,CHANNEL_1);
    TIMER_setupIC(TIMER_4,CHANNEL_2);
    TIMER_setupIC(TIMER_4,CHANNEL_3);
    TIMER_setupIC(TIMER_4,CHANNEL_4);
    //Change duty cycle and pulse output
    TIMER_setDuty(TIMER_1,CHANNEL_1,80);
    TIMER_setPulse(TIMER_1,CHANNEL_2,100);
    TIMER_setDuty(TIMER_1,CHANNEL_2,10);
    while (1){
        if(flag){
            flag = 0;
            //Time how long it takes to compete print function with TIMER_3
            TIMER_setCount(TIMER_3,0);
            //Print input capture values
            printt(TIMER_getIC(TIMER_4,CHANNEL_1));
            printt(TIMER_getIC(TIMER_4,CHANNEL_2));
            printt(TIMER_getIC(TIMER_4,CHANNEL_3));
            printt(TIMER_getIC(TIMER_4,CHANNEL_4));
            printl(TIMER_getCount(TIMER_3)); //Printing the time difference
        }
    }
    return 0;
}
//This is called by TIMER_3 on timeout
void up(void){
    flag = 1;
}

Enumeration Type Documentation

enum timer_channel

Timers channels available for each timer.

Enumerator
CHANNEL_1	Channel 1.
CHANNEL_2	Channel 2.

Definition at line 76 of file attiny13a_timer.h.

enum timer_main

Main timers available on the MCU.

Enumerator
TIMER_0	Timer 0.

Definition at line 68 of file attiny13a_timer.h.

Function Documentation

mcu_error TIMER_disableISR ( timer_main timerNumber )

Disable the timeout IRQ.

This disables any previous use of timeout interrupts.

Parameters

timerNumber The timer number to modify (not used)

Returns: Error number as defined in mcu_error, E_TIMER_NOERROR if no error.

mcu_error TIMER_enableISR	(	timer_main	timerNumber,
		void(*)(void)	handler
	)

Set the ISR target for timeout.

This feature can be used for Count, Pulse and PWM modes. Function is called on timeout event recursively until TIMER_disableISR() is used.

Parameters

timerNumber	The timer number to modify (not used)
handler	The function to call on timeout

Returns: Error number as defined in mcu_error, E_TIMER_NOERROR if no error.

uint8_t TIMER_getCount ( timer_main timerNumber )

Get the current value of a running timer.

The resolution of the value returned depends of the frequency of timer as setup.

Parameters

timerNumber The timer number to modify (not used)

Returns: The current value of the timer.

Definition at line 297 of file attiny13a_timer.c.

uint16_t TIMER_getIC	(	timer_main	timerNumber,
		timer_channel	channel
	)

Get the last input capture time from a channel of a timer.

The timer must be setup with TIMER_setupIC() for this function to work.

Parameters

timerNumber	The timer number to modify (not used)
channel	The timer channel to modify

Note: This function returns 0 if called twice when no reading has occured.

Returns: The last input capture time in microseconds

mcu_error TIMER_pause ( timer_main timerNumber )

Pause an already running timer.

The timer must have been already setup to use this.

Parameters

timerNumber The timer number to modify (not used)

Returns: Error number as defined in mcu_error, E_TIMER_NOERROR if no error, E_TIMER_PORT if port doesn't exist.

Definition at line 113 of file attiny13a_timer.c.

mcu_error TIMER_resume ( timer_main timerNumber )

Resume a paused timer.

Due to the internal register configuration of the ATTINY13A the timer needs to be restarted with one of the setup functions. E.g TIMER_setupCount()

Warning: This should not be used to restart a paused timer for the ATTINY13a.

Parameters

timerNumber The timer number to modify (not used)

Returns: Error number as defined in mcu_error, E_TIMER_NOERROR if no error.

Definition at line 122 of file attiny13a_timer.c.

mcu_error TIMER_setCount	(	timer_main	timerNumber,
		uint8_t	count
	)

Set the current value of a running timer.

Parameters

timerNumber	The timer number to modify (not used)
count	The timer value

Returns: The current value of the timer.

Definition at line 303 of file attiny13a_timer.c.

mcu_error TIMER_setDuty	(	timer_main	timerNumber,
		timer_channel	channel,
		uint8_t	duty
	)

Set the duty cycle for the waveform (PWM only, 0 - 100%).

Parameters

timerNumber	The timer number to modify (not used)
channel	The timer chanel to modify
duty	The desired duty cycle.

Returns: Error number as defined in mcu_error, E_TIMER_NOERROR if no error, E_TIMER_PORT if port doesn't exist

Definition at line 312 of file attiny13a_timer.c.

mcu_error TIMER_setFrequency	(	timer_main	timerNumber,
		uint16_t	frequency
	)

Set the frequency for the timer. (in hertz)

The minimum and maximum frequency value that can be represented are dependant on the frequency of the main clock as specified:

F_CPU	Minimum	Maximum
9.6MHz	40Hz	10kHz
4.8MHz	20Hz	5kHz
1.2MHz	5Hz	2.5kHz
0.6MHz	3Hz	1.25kHz

Parameters

timerNumber	The timer number to modify (not used)
frequency	The desired timeout frequency.

Returns: Error number as defined in mcu_error, E_TIMER_NOERROR if no error, E_TIMER_PORT if port doesn't exist E_TIMER_PERIOD if the period is too long

mcu_error TIMER_setPeriod	(	timer_main	timerNumber,
		uint32_t	period
	)

Set the period for the timer. (in microseconds)

The minimum and maximum periods that can be represented are dependant on the frequency of the main clock as specified:

F_CPU	Minimum	Maximum
9.6MHz	100us	25ms
4.8MHz	200us	50ms
1.2MHz	800us	200ms
0.6MHz	1.6ms	400ms

Parameters

timerNumber	The timer number to modify (not used)
period	The desired timeout period.

Returns: Error number as defined in mcu_error, E_TIMER_NOERROR if no error, E_TIMER_PORT if port doesn't exist E_TIMER_PERIOD if the period is too long

mcu_error TIMER_setPulse	(	timer_main	timerNumber,
		timer_channel	channel,
		uint16_t	pulse
	)

Set the pulse width for the output. (in milliseconds)

The resolution and period of the pulse widths are limited by the clock frequency as follows:

F_CPU	Period	Resolution
9.6MHz	6.8ms	26.6us
4.8MHz	13.6ms	53.3us
1.2MHz	13.5ms	53.3us
0.6MHz	27.9ms	106us

Parameters

timerNumber	The timer number to modify (not used)
channel	The timer channel to modify
pulse	The desired pulse width.

Returns: Error number as defined in mcu_error, E_TIMER_NOERROR if no error, E_TIMER_PORT if port doesn't exist E_TIMER_PULSE if the pulse is too long

Definition at line 326 of file attiny13a_timer.c.

mcu_error TIMER_setupCount	(	timer_main	timerNumber,
		uint16_t	frequency,
		void(*)(void)	handler
	)

Initialize given timer for standard count with interrupt trigging the function handler on timeout.

The minimum and maximum frequency value that can be represented are dependant on the frequency of the main clock as specified:

F_CPU	Minimum	Maximum
9.6MHz	40Hz	10kHz
4.8MHz	20Hz	5kHz
1.2MHz	5Hz	2.5kHz
0.6MHz	3Hz	1.25kHz

Parameters

timerNumber	The timer number to setup (not used)
handler	The function to call on timeout event.
frequency	The frequency of the timer count expiration.

Warning: TIMER_ISR needs to be uncommented in the makefile for this to work

Returns: Error number as defined in mcu_error, E_TIMER_NOERROR if no error, E_TIMER_PORT if port doesn't exist.

mcu_error TIMER_setupIC	(	timer_main	timerNumber,
		timer_channel	timerChannel
	)

Initialize given timer for input capture.

The input capture channel is fixed to PORTB, PIN4. This can be changed by adding the compiler flag -DIC_PIN=xxx, where xxx is the pin number defined by gpio_pin.

Warning: Input capture and external pin interrupts cannot be used at the same time, as input capture uses external interrupts.

Note: TIMER_IC needs to be uncommented in the makefile for this to work

The signal period and pulse resolution is dependant on the clock frequency of the device, as set in the Makefile.

F_CPU	Period	Resolution
9.6MHz	6.8ms	26.6us
4.8MHz	13.6ms	53.3us
1.2MHz	13.5ms	53.3us
0.6MHz	27.9ms	106us

Parameters

timerNumber	The timer number to setup (not used)
timerChannel	The channel of that timer to use. (not used)

Returns: Error number as defined in mcu_error, E_TIMER_NOERROR if no error, E_TIMER_PORT if port doesn't exist.

mcu_error TIMER_setupPulse	(	timer_main	timerNumber,
		timer_channel	timerChannel,
		uint16_t	frequency,
		uint16_t	pulse
	)

Initialize given timer for Pulse mode.

The given timer number timer_main is now locked to this pulse or PWM modes.

All channels of this timer can only be used for pulse of PWM. Each channel must also share the same frequency. However each channel can be turned on and off

The signal period and pulse resolution is dependant on the clock frequency of the device, as set in the Makefile.

F_CPU	Period	Resolution
9.6MHz	6.8ms	26.6us
4.8MHz	13.6ms	53.3us
1.2MHz	13.5ms	53.3us
0.6MHz	27.9ms	106us

Parameters

timerNumber	The timer number to setup (not used)
timerChannel	The channel of that timer to use.
frequency	The frequency of the total signal. (not used)
pulse	The initial pulse width of the signal.

Returns: Error number as defined in mcu_error, E_TIMER_NOERROR if no error, E_TIMER_PORT if port doesn't exist

Definition at line 251 of file attiny13a_timer.c.

mcu_error TIMER_setupPWM	(	timer_main	timerNumber,
		timer_channel	timerChannel,
		uint16_t	frequency,
		uint8_t	duty
	)

Initialize given timer for PWM mode.

The given timer number timer_main is now locked to this or pulse mode.

All channels of this timer can only be used for PWM of Pulse width output. Each channel must also share the same frequency. However each channel can be turned on and off

The frequency of the PWM waveform is determined by the clock frequency as follows:

F_CPU	Frequency
9.6MHz	37.5kHz
4.8MHz	18.75kHz
1.2MHz	4.69kHz
0.6MHz	2.3kHz

Parameters

timerNumber	The timer number to setup (not used)
timerChannel	The channel of that timer to use.
frequency	The frequency of the signal. (not used)
duty	The initial duty cycle.

Returns: Error number as defined in mcu_error, E_TIMER_NOERROR if no error, E_TIMER_PORT if port doesn't exist

Definition at line 220 of file attiny13a_timer.c.

Files

Macros

Enumerations

Functions

Detailed Description

Enumeration Type Documentation

Function Documentation