Datasheet

TMS320F28027, TMS320F28026, TMS320F28023, TMS320F28022
TMS320F28021, TMS320F28020, TMS320F280200
SPRS523J –NOVEMBER 2008–REVISED OCTOBER 2013 www.ti.com
3.2.14 Peripheral Clocking
The clocks to each individual peripheral can be enabled/disabled to reduce power consumption when a
peripheral is not in use. Additionally, the system clock to the serial ports (except I
2
C) can be scaled
relative to the CPU clock.
3.2.15 Low-power Modes
The devices are full static CMOS devices. Three low-power modes are provided:
IDLE: Place CPU in low-power mode. Peripheral clocks may be turned off selectively and
only those peripherals that need to function during IDLE are left operating. An
enabled interrupt from an active peripheral or the watchdog timer will wake the
processor from IDLE mode.
STANDBY: Turns off clock to CPU and peripherals. This mode leaves the oscillator and PLL
functional. An external interrupt event will wake the processor and the peripherals.
Execution begins on the next valid cycle after detection of the interrupt event
HALT: This mode basically shuts down the device and places it in the lowest possible power
consumption mode. If the internal zero-pin oscillators are used as the clock source,
the HALT mode turns them off, by default. To keep these oscillators from shutting
down, the INTOSCnHALTI bits in CLKCTL register may be used. The zero-pin
oscillators may thus be used to clock the CPU-watchdog in this mode. If the on-chip
crystal oscillator is used as the clock source, it is shut down in this mode. A reset or
an external signal (through a GPIO pin) or the CPU-watchdog can wake the device
from this mode.
The CPU clock (OSCCLK) and WDCLK should be from the same clock source before attempting to put
the device into HALT or STANDBY.
3.2.16 Peripheral Frames 0, 1, 2 (PFn)
The device segregates peripherals into three sections. The mapping of peripherals is as follows:
PF0: PIE: PIE Interrupt Enable and Control Registers Plus PIE Vector Table
Flash: Flash Waitstate Registers
Timers: CPU-Timers 0, 1, 2 Registers
CSM: Code Security Module KEY Registers
ADC: ADC Result Registers
PF1: GPIO: GPIO MUX Configuration and Control Registers
ePWM: Enhanced Pulse Width Modulator Module and Registers
eCAP: Enhanced Capture Module and Registers
Comparators: Comparator Modules
PF2: SYS: System Control Registers
SCI: Serial Communications Interface (SCI) Control and RX/TX Registers
SPI: Serial Port Interface (SPI) Control and RX/TX Registers
ADC: ADC Status, Control, and Configuration Registers
I
2
C: Inter-Integrated Circuit Module and Registers
XINT: External Interrupt Registers
28 Functional Overview Copyright © 2008–2013, Texas Instruments Incorporated
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TMS320F28020 TMS320F280200