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EW: Microchip 8bit MCUs get up to 128kbyte flash

Microchip PIC18(L)F24-25K42

The firm has gone big on its ‘core independent peripherals’ (CIP) to allow functions to be implemented in hardware, saving code, validation time, core overhead, and power consumption, said Microchip.

Intended for automotive, industrial control, IoT, medical and white goods, they include peripherals for safety critical applications including cyclic redundancy check with memory scan, a windowed watchdog timer, a 24bit signal measurement timer and a hardware limit timer, as well as up to eight hardware PWMs, complementary waveform generation for power bridges, and multiple communications interfaces.

Analogue peripherals including a zero crossing detector, constant current I/O (see below), a comparator, and a 12bit ADC with computation – the latter for automating capacitive voltage division (for touch sensing), averaging, filtering, over-sampling, and threshold comparison.

Constant current I/O

The constant current I/O feature allows the sink and source current of a pin to be set to 1, 2, 5 or 10mA. This has to be used with caution because the pin circuitry cannot dissipate much static power, so an “external resistor must be inserted in series with the load to dissipate most of the power,” said Microchip.

It has an example, with a 5V rail and a load which needs 1mA and whose voltage drop can be between 1.0 and 1.5V. The external resistor and pin circuitry has to make up 3.5-4V difference, so the resistor  needs to be chosen to drop 3.5V at of 1 mA, said Microchip, then the pin can make up the 0-500mV variable difference.

A ‘memory access partition’ supports data protection and bootloading, and the ‘device information area’ is a dedicated memory space for factory programmed device ID and peripheral calibration values.

Building blocks

  • ADC with computation
  • zero crossing detector
  • 10bit PMW
  • complementary waveform generator
  • numerically controlled oscillator
  • data signal modulator
  • hardware limit timer
  • 24bit signal measurement timer
  • configurable logic cell
  • crc/scan module
  • windowed watchdog timer
  • peripheral pin select
  • direct memory access
  • temperature indicator
  • data signal modulator
  • 5bit DAC
  • UART, SPI, and I2C