SPRUJ53B April 2024 – September 2024 TMS320F28P550SJ , TMS320F28P559SJ-Q1
HALT is a global low-power mode that gates almost all system clocks and allows for power-down of oscillators and analog blocks.
Unlike on other C2000™ devices, HALT mode does not automatically power down the XTAL upon HALT entry. Additionally, if the XTAL is not powered on, waking up from HALT mode does not automatically power on the XTAL. The XTALCR.OSCOFF bit has been added to power on and off the XTAL circuitry when not needed through application software.
For applications that require minimal power consumption during HALT mode, application software can power off the XTAL prior to entering HALT. If the OSCCLK source is configured to be XTAL, the application can first switch the OSSCLK source to INTOSC1 or INTOSC2 prior to setting XTALCR.OSCOFF.
Each GPIO can be configured to wake up the system from HALT. No other wake up option is available. However, the watchdog timer can still be clocked, and can be configured to produce a watchdog reset if a timeout mechanism is needed. On wake up, the CPU receives a WAKEINT interrupt.
To enter HALT mode:
If an interrupt or NMI is received while the IDLE instruction is in the pipeline, the system begins executing the WAKEINT ISR. After HALT wake up, ISR execution resumes where execution left off.
To wake up from HALT mode:
The device is now out of HALT mode and can resume normal execution.