Frequency Adjustment

1. Overview

CPU frequency=800MHz, Core Power 0.9V

CPU frequency=1GHz, Core Power 1.0V

Regardless of the CPU frequency software setting, Core Power = 1V is required.

Recommendation: Keep the DVFS circuit, start at 1V, and select the voltage according to the frequency configured by the software after the start.

If you need to fix Core Power, please confirm with SigmaStar first.

2. Software Fixed Frequency (1G)

Note:

  1. Fixed cpu frequency in kernel\arch\arm\boot\dts\pioneer3.dtsi, such as fixed to 1Ghz.

  2. After enabling CONFIG_SS_VOLTAGE_CTRL in kernel config, the software will control the core pin.

  3. In the IPL/UBOOT phase, the software does not control DVFS. After KERNEL runs, it will set Core Power=1.0V.

  4. The pin that dynamically adjusts the core voltage by the hardware is connected to the relevant circuit.

  5. Measure the actual value, whether it is maintained at 1.0V from power-on to IPL/UBOOT/KERNEL.

3. Fixed Frequency (800M)

Note：

  1. Fixed cpu frequency in kernel\arch\arm\boot\dts\pioneer3.dtsi, such as fixed to 800M.

  2. After enabling CONFIG_SS_VOLTAGE_CTRL in kernel config, the software will control the core pin.

  3. In the IPL/UBOOT phase, the software does not control DVFS. After KERNEL runs, it will set Core Power=0.9V.

  4. The pin that dynamically adjusts the core voltage by the hardware is connected to the relevant circuit.

  5. Measure the actual value, whether it is maintained at 1.0V from power-on to IPL/UBOOT/KERNEL, but switched to 0.9V after kernel is running (CPU 800MHz).

4. Dynamic Frequency(1G/800M)

Note:

  1. Fixed cpu frequency in kernel\arch\arm\boot\dts\pioneer3.dtsi, such as fixed to 800M.

  2. After enabling CONFIG_SS_VOLTAGE_CTRL in kernel config, the software will control the core pin.

  3. In the IPL/UBOOT phase, the software does not control DVFS. After KERNEL runs, it will set Core Power=0.9V.

  4. The pin that dynamically adjusts the core voltage by the hardware is connected to the relevant circuit.

  5. Measure the actual value, whether it is maintained at 1.0V from power-on to IPL/UBOOT, but switch Core Power according to the frequency selected by the software after kernel is running, CPU 800MHz -> 0.9V or CPU 1G -> 1.0V.

The current cpu frequency can be viewed by cat /sys/devices/system/cpu/cpufreq/policy0/cpuinfo_cur_freq.

cpu loading: