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What is alternate function in GPIO?
GPIO alternate functions are used to support two sets of Arduino shield expansion peripherals. The 52-pin expansion port (EXP port) is driven from GPIO0-3. For each pin, the relevant bit of ALTFUNC must be set to use the alternate function. If this bit is not set to use the alternate function, the pin is used for GPIO.
What is alternate function STM32?
In addition to acting as General Purpose I/Os, many of the pins on the STM32 microcontrollers have one or more alternate functions. These alternate functions are tied to subsystems inside the MCU, such as one or more SPI, I2C, USART, Timer, DMA or other peripherals.
What is alternate function mode?
In the alternate function mode, as the name indicates, the pin will be assigned for alternate functionality. The alternate functionality can be anything like UART-TX, UART-RX, timers input channel or ADC’s input channel, etc…
Which port is used as multi function port?
Port 3 is multifunction part it can be used as a simple input/output port.
What is the difference between push pull and open drain?
While a push-pull sensor has two MOSFETs that alternately conduct to provide high or low output signals, an open drain sensor has only one MOSFET. When a magnetic field turns the open-drain sensor on, the MOSFET conducts, allowing current to sink through the pull-up resistor to ground.
What are the alternate functions of port 3?
Port 3 is multifunction part it can be used as a simple input/output port. Port 3 as simple input port: When port 3 is used as an input port ‘1’ must be written to the corresponding port 3 latch bit this cause the FET to turn off pin & input to pin buffer are pulled to logic high by internal pull up load.
What’s the alternate pin function on a GPIO?
This is called Peripheral Pin Select, and basically means you can select which pin your peripheral is using. You could, for example, do RS232 over RA1 and RA2 or over RB1 and RB2.
Are there any alternate functions on the Raspberry Pi?
The blank ones are simply not implemented. For the full gory tale, the BCM2835 ARM Peripherals document is where you want to look, but here’s a quick look at some of the functions: ALT 0: Where most of the interesting and useful alternate functions are as far as the Raspberry Pi is concerned.
How are alternate functions selected in a processor?
functions, which are called alternate functions. The alternate function is selected by programming the AFSEL[3:0] bits defined in the Alternate Function Low or High Register. Alternate functions allow embedded system designers to better tailor the processor chip to the application’s need. AFSEL0[3:0]
What’s the alternate pin function on a microcontroller?
Some microcontrollers have the option to switch their internal peripherals between several sets of IO lines. This way, you can avoid issues if you want to use internal modules (SPI, I2C, etc…) that have their functions mapped to the same set of pins.