Clock Control
132
SPRUH22I – April 2012 – Revised November 2019
Copyright © 2012–2019, Texas Instruments Incorporated
System Control and Interrupts
1.8.4.2
C28x Idle Mode
In idle mode, the C28x processor stops executing instructions and the C28CPUCLK is turned off. The
C28SYSCLK continues to run. Exit from idle mode is accomplished by any enabled interrupt or the
C28NMIINT (C28x non-maskable interrupt). Upon exit from idle mode, the C28CPUCLK is restored. If
LPMWAKE interrupt is enabled, the LPMWAKE ISR is executed. Next, the C28x processor starts fetching
instructions from a location immediately following the IDLE instruction that originally triggered the idle
mode.
1.8.4.3
C28x Standby Mode
In standby mode, the C28x processor stops executing instructions and the C28CLKIN, C28CPUCLK, and
C28SYSCLK are turned off. Exit from Standby Mode is accomplished by one of 64 GPIOs from the
GPIO_MUX block, or MTOCIPCINT2 (interrupt from the MTOC IPC peripheral). The wakeup GPIO
selected inside the GPIO_MUX block enters the Qualification Block as the LPMWAKE signal. Inside the
Qualification Block, the LPMWAKE signal is qualified per the QUALSTDBY bits (bits [7:2] of the
CLPMCR0 register) before propagating into the wake request logic. Upon exit from STANDBY Mode, the
C28CLKIN, C28SYSCLK, and C28CPUCLK are restored. If the LPMWAKE interrupt is enabled, the
LPMWAKE ISR is executed. Next, the C28x processor starts fetching instructions from a location
immediately following the IDLE instruction that originally triggered the Standby Mode.
1.8.4.4
Control Peripherals Clocking
The clocking control for the C28 subsystem is done with the PCLKCR0, PCLKCR1, PCLKCR2, and
PCLKCR3 registers. These registers are accessible only by the C28 CPU and are similar to earlier C2000
family of devices.
shows various clock domain on the control subsystem.