Peripheral Pin Select on PIC24 MCUs



the first devices to contain the peripheral pin select will be the pick 24 FG a 64 G a 0 0 4 family this family of devices is part of our pick 24 F series of microcontrollers at 16 bits per formance the pick 24 F devices are meant to be the 16-bit entry point for our 8-bit customers and need additional performance flash or SRAM the pick 24 FJ 64 family is specifically targeted at opening our 16-bit product line the customers requiring smaller packages lower pin counts and more SRAM as I mentioned the pick 24 F is meant to be a cost-effective first step into our 16-bit products microchip offers four 16-bit cores that share common core architecture instruction set development tools peripherals and pin outs a designer using microchip 16-bit products can balance their controller selection based on cost performance peripherals and even DSP capability all for the 16-bit families use the same tool set which allows a smooth transition without the need to learn or purchase new tools the pic 24 FJ 64 GA 0:04 family is the latest addition to the pic 24 f-series it adds 28 and 44 pin packages with flash memory densities of 16 32 48 and 64 K bytes SRAM on the 16 K flash device is 4k the other devices in the family have 8k of SRAM the device is designed to bring microchips 16-bit products to low pen count applications it also provides a performance and SRAM upgrade path to 8-bit users if you're familiar with our pic 24 FG a 128 family you will note that the peripheral set is very similar in fact with the exception of a few ADC channels the peripheral set is the same as our hundred pin device features include a 10 bit A to D converter to comparators 5 16-bit timers v input capture and v output compared pwms the device is also very rich in serial peripherals with two independent channels of you are I squared C and spy device also includes our real-time clock calendar our cyclic redundancy check and parallel master port the final feature of this device is the peripheral pin selector PPS as you will see it is the peripheral pin select that makes it effective to integrate a large peripheral set on a 28 pin device as I reviewed the peripheral set on the pic 24 FJ 64 I mentioned that the peripheral set was the same as the hunter pen picked 24 FJ 128 device to fully utilize the peripheral set included on this device over 80 functions are available for pin out the 80 functions do not include standard IO power or oscillator pins on a hundred pin device it may be realistic to utilize a large peripheral set on a smaller pin count device it is impossible to fully utilize a large feature set so the peripheral sets are typically smaller this makes it difficult for a designer who's developing a system that requires a feature-rich device for example an application that requires numerous serial channels if a typical microcontroller was designed with multiple you arts spies and I squared sees their use would be limited by the way the pins are typically multiplex in most microcontrollers the functional inputs and outputs of a peripheral are typically multiplexed on fixed pins and often conflict with each other this creates a situation where by selecting one peripheral you lose the ability to use another if a microcontroller manufacturer included all the needed peripherals on an IC it wouldn't be possible to access the peripherals needed peripheral pin select addresses the issue of how to access the peripherals needed with as few pins as possible on devices with peripheral pin select there are a number of pins designated remappable peripherals or RPN pins the RPN can be used to access any of the remappable peripherals avoiding the pin multiplexing issues found out many microcontrollers in short you can access the exact peripherals you need for your application

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