What this 8-bit PIC brings to a 64 MHz design
The Microchip PIC18F56Q43-E/PT is an 8-bit PIC MCU from the PIC® XLP™ 18F family, built for applications that need a 64 MHz core clock without moving to a 16- or 32-bit architecture.
At 64 MHz, this part executes most single-cycle instructions in about 15.6 ns. That is fast enough to bit-bang a software UART at 1 Mbps, run a PID loop with 10 kHz update rate, or drive a PWM carrier at 32 kHz with 10-bit resolution — all without a dedicated peripheral. Flash wait states matter at this speed: the first instruction fetch after a branch may stall one cycle, so interrupt latency budgets should account for that.
Memory map and non-volatile storage
The 64 KB Flash is organized as 64K x 8, giving 65,536 byte-addressable locations — enough for a modest bootloader plus application code. The 4 KB RAM (4K x 8) handles typical data buffers and stack; if your application needs larger frame buffers or double-buffered DMA, the 4 KB ceiling is a hard limit to size early. The 1 KB EEPROM (1K x 8) is useful for calibration constants, configuration parameters, or fault logs that must survive a power cycle without wearing the Flash. EEPROM endurance is typically 100k erase/write cycles per byte, which outlasts most product lifetimes for infrequent writes.
Analog integration: 12-bit ADC and 8-bit DAC
With 43 analog inputs multiplexed into a 12-bit ADC, this MCU can monitor a dozen thermistors, several voltage rails, and a current-sense resistor without an external mux. The 12-bit resolution gives 1.22 mV per LSB at a 5 V reference — adequate for 0.1°C temperature sensing with a standard NTC. The single 8-bit DAC provides a 0-to-Vref analog output for set-point generation or simple waveform synthesis. Both converters share the same voltage reference, so the DAC output can directly drive the ADC input for self-test loops.
On-chip peripherals include brown-out detect, low-voltage detect, power-on reset, PWM, and watchdog timer — the usual safety and housekeeping blocks that reduce external supervisor ICs.
The part is ROHS3 compliant. If you are planning a multi-year production run, the active status and wide temperature grade make this a low-obsolescence-risk choice, but always check for PCN notifications if the design is long-lived.