PIC32MX Oscillator - System Clock (SYSCLK)

System Clock (SYSCLK) Generation


The System Clock provides the time base for the CPU, peripheral clock, DMA, interrupts and flash. SYSCLK is determined from one of the input clocks shown in the diagram: System PLL output (POSC or FRC with PLL), POSC, FRC, FRCDIV16, FRCDIV, LPRC, or SOSC.

Note: The PIC32MZ uses the Peripheral Bus Clock #7 (PBCLK7) to drive the core as SYSCLK.

The default configuration for SYSCLK is programmable and can also be changed at run-time. See the code examples below.

// default system clock = FRCDIV
#pragma config FNOSC = FRCDIV
// default system clock = Primary OSC (XT, HS, EC) with PLL
#pragma config FNOSC = PRIPLL
// run-time config SYSCLK = FRCDIV
// run-time config SYSCLK = POSC with PLL

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