To extend this core's functionality a bit further, I've added a few missing Wiring functions. As many of you know Arduino is based on Wiring, but that doesn't mean the Wiring development isnt active. These functions are used as "regular" Arduino functions, and there's no need to include an external library.
- portMode()
- portRead()
- portWrite()
- sleepMode()
- sleep()
- noSleep()
- enablePower()
- disablePower()
The portMode() method sets a specified digital I/O port as INPUT or OUTPUT. A digital I/O port is a group of 8 pins. By writing 0 to a port it will individually set each of the 8 pins to 0 (LOW). Possible values range from 0 to 255. It possible to read or write a value of a digital I/O port by using the portRead() and portWrite() methods.
portMode(portNumber, value)portNumber - byte/uint8_t
value - byte/uint8_t
| PortNumber | Physical port |
|---|---|
| 0 | PORTA |
| 1 | PORTB |
| 2 | PORTC |
| 3 | PORTD |
| 4 | PORTE * |
* ATmega324PB only
none
byte portNumber = 1; // Use port B
byte val = 0;
void setup() {
portMode(portNumber, OUTPUT);
}
void loop() {
portWrite(portNumber, val);
val = val + 1;
if (val > 255)
val = 0;
}The portRead() method reads the value of the digital input port specified.
portRead(portNumber)portNumber - byte/uint8_t
| PortNumber | Physical port |
|---|---|
| 0 | PORTA |
| 1 | PORTB |
| 2 | PORTC |
| 3 | PORTD |
| 4 | PORTE * |
* ATmega324PB only
byte/uint8_t
byte portNumber = 1; // Use port B
byte val = 0;
void setup() {
portMode(portNumber, INPUT);
Serial.begin(9600);
}
void loop() {
val = portRead(portNumber);
Serial.print(val);
}The portWrite() method writes a value to the digital output port specified.
portWrite(portNumber, value)portNumber - byte/uint8_t
value - byte/uint8_t
| PortNumber | Physical port |
|---|---|
| 0 | PORTA |
| 1 | PORTB |
| 2 | PORTC |
| 3 | PORTD |
| 4 | PORTE * |
* ATmega324PB only
none
byte portNumber = 1; // Use port B
byte val = 0;
void setup() {
portMode(portNumber, OUTPUT);
}
void loop() {
portWrite(portNumber, val);
val = val + 1;
if (val > 255)
val = 0;
}Sleep mode enables the application to shut down unused modules in the microcontroller, thereby saving power. The default mode is SLEEP_IDLE. Different AVR devices provide various sleep modes allowing the user to tailor the power consumption to the application's requirements. There are six sleep modes set by the sleepMode() command.
SLEEP_IDLE:
Makes the MCU enter Idle mode, stopping the CPU but allowing the SPI, Serial, Analog Comparator, ADC, Wire, Timer/Counters and the interrupt system to continue operating. This mode enables the microcontroller to wake up from external triggered interrupts as well as internal ones like the Timer Overflow and Serial Transmit Complete interrupts.
SLEEP_ADC:
Makes the microcontroller enter ADC Noise Reduction mode, stopping the CPU but allowing the ADC, the external interrupts, Wire Serial Interface address match and Timer/Counter2. This improves the noise environment for the ADC, enabling higher resolution measurements. If the ADC is enabled, a conversion starts automatically when this mode is entered. Only an External Reset, a Wire serial interface interrupt, a Timer/Counter2 interrupt, an SPM/EEPROM ready interrupt, an external level interrupt on INT7:4 or a pin change interrupt can wakeup the microcontroller from ADC Noise Reduction mode.
SLEEP_POWER_DOWN:
In this mode, the external Oscillator is stopped, while the external interrupts, and the Wire Serial Interface continue operating. Only an External Reset, Wire Serial Interface address match, an external level interrupt on INT7:4, an external interrupt on INT3:0, or a pin change interrupt can wake up the microcontroller. This sleep mode basically halts all generated clocks, allowing operation of asynchronous modules only.
SLEEP_POWER_SAVE:
This mode is identical to SLEEP_POWER_DOWN, with one exception: If Timer/Counter2 is enabled, it will keep running during sleep. The device can wake up from either Timer Overflow or Output Compare event from Timer/Counter2 if the corresponding Timer/Counter2 interrupt enable bits are set, and the Global Interrupts are enable. If Timer/Counter2 is not running, SLEEP_POWER_DOWN mode is recommended instead of SLEEP_POWER_SAVE mode. The Timer/Counter2 can be clocked both synchronously and asynchronously in SLEEP_POWER_SAVE mode. If the Timer/Counter2 is not using the asynchronous clock, the Timer/Counter Oscillator is stopped during sleep. If the Timer/Counter2 is not using the synchronous clock, the clock source is stopped during sleep. Note that even if the synchronous clock is running in SLEEP_POWER_SAVE, this clock is only available for the Timer/Counter2.
SLEEP_STANDBY:
This mode is identical to SLEEP_POWER_SAVE mode with the exception that the Oscillator is kept running.
SLEEP_EXTENDED_STANDBY:
This mode is identical to SLEEP_POWER_SAVE mode with the exception that the Oscillator is kept running. From SLEEP_EXTENDED_STANDBY mode, the device wakes up in six clock cycles.
sleepMode(mode)mode - byte/uint8_t
| Mode |
|---|
| SLEEP_IDLE |
| SLEEP_ADC |
| SLEEP_POWER_DOWN |
| SLEEP_POWER_SAVE |
| SLEEP_STANDBY |
| SLEEP_EXTENDED_STANDBY |
none
// ...
// Set the sleep mode to SLEEP_IDLE
sleepMode(SLEEP_IDLE);
sleep(); // Go to sleep
if(some_condition)
noSleep(); // Wakes up
// ...The sleep() command can allow an application to reduce its power consumption considerably. Sleep mode enables the application to shut down unused modules in the microcontroller, thereby saving power. The default mode is SLEEP_IDLE. Different AVR devices provide various sleep modes allowing the user to tailor the power consumption to the application's requirements. There are six sleep modes set by the sleepMode() command.
sleep()none
// ...
// Set the sleep mode to SLEEP_IDLE
sleepMode(SLEEP_IDLE);
sleep(); // Go to sleep
if(some_condition)
noSleep(); // Wakes up
// ...The noSleep() command wakes up the microcontroller from a previous sleep(). Sleep mode enables the application to shut down unused modules in the microcontroller, thereby saving power. The default mode is SLEEP_IDLE. Different AVR devices provide various sleep modes allowing the user to tailor the power consumption to the application's requirements. There are six sleep modes set by the sleepMode() command.
noSleep()none
// ...
// Set the sleep mode to SLEEP_IDLE
sleepMode(SLEEP_IDLE);
sleep(); // Go to sleep
if(some_condition)
noSleep(); // Wakes up
// ...The enablePower() and disablePower() methods enable and disable power to specific devices or sections of the Wiring hardware. By default power is enabled in all sections on the Wiring board. Note that the Wiring functionality regarding a specific section will stop by disabling power. These methods are useful for efficient power management in conditions where power is very limited or has to be very efficient. The methods are provided for advanced users who know exactly what they are doing. Sections / features are encapsulated by constants as follow: POWER_ADC (analog input), POWER_SPI (SPI), POWER_WIRE (Wire), POWER_TIMER0 (Timer0, disabling this will stop all Wiring activity), POWER_TIMER1 (Timer1), POWER_TIMER2 (Timer2), POWER_TIMER3 (Timer3), POWER_SERIAL0 (Serial), POWER_SERIAL1 (Serial1) and POWER_ALL (all the above). The power management functions provide a method to stop the clock to individual peripherals to reduce power consumption. Note: calling enablePower() or disablePower() commands might have no effect on ATmega32, ATmega16 and ATmega8535.
enablePower(section)section - byte/uint8_t
| Section |
|---|
| POWER_ADC |
| POWER_SPI |
| POWER_WIRE |
| POWER_TIMER0 |
| POWER_TIMER1 |
| POWER_TIMER2 |
| POWER_TIMER3 |
| POWER_SERIAL0 |
| POWER_SERIAL1 |
| POWER_ALL |
none
// ...
// enable Analog Input section have power
enablePower(POWER_ADC);
// ...
// enable power in all sections/features
// of the microcontroller
enablePower(POWER_ALL);
// ...The enablePower() and disablePower() methods enable and disable power to specific devices or sections of the Wiring hardware. By default power is enabled in all sections on the Wiring board. Note that the Wiring functionality regarding a specific section will stop by disabling power. These methods are useful for efficient power management in conditions where power is very limited or has to be very efficient. The methods are provided for advanced users who know exactly what they are doing. Sections / features are encapsulated by constants as follow: POWER_ADC (analog input), POWER_SPI (SPI), POWER_WIRE (Wire), POWER_TIMER0 (Timer0, disabling this will stop all Wiring activity), POWER_TIMER1 (Timer1), POWER_TIMER2 (Timer2), POWER_TIMER3 (Timer3), POWER_SERIAL0 (Serial), POWER_SERIAL1 (Serial1) and POWER_ALL (all the above). The power management functions provide a method to stop the clock to individual peripherals to reduce power consumption. Note: calling enablePower() or disablePower() commands might have no effect on ATmega32, ATmega16 and ATmega8535.
disablePower(section)section - byte/uint8_t
| Section |
|---|
| POWER_ADC |
| POWER_SPI |
| POWER_WIRE |
| POWER_TIMER0 |
| POWER_TIMER1 |
| POWER_TIMER2 |
| POWER_TIMER3 |
| POWER_SERIAL0 |
| POWER_SERIAL1 |
| POWER_ALL |
none
// ...
// disable power on Analog Input section
disablePower(POWER_ADC);
// ...
// disable power on Serial0
disablePower(POWER_SERIAL0);
// ...