例程讲解-02-cpufreq_scaling CPU频率缩放

# CPU频率缩放示例。
#
# 此示例显示如何使用cpufreq模块动态更改CPU频率。
import sensor, image, time, cpufreq

sensor.reset()                          # Reset and initialize the sensor.
sensor.set_pixformat(sensor.GRAYSCALE)  # Set pixel format to RGB565 (or GRAYSCALE)
sensor.set_framesize(sensor.QQVGA)      # Set frame size to QVGA (320x240)
sensor.skip_frames(time = 2000)         # Wait for settings take effect.
clock = time.clock()                    # Create a clock object to track the FPS.

def test_image_processing():
    for i in range(0, 50):
        clock.tick()                    # Update the FPS clock.
        img = sensor.snapshot()         # Take a picture and return the image.
        img.find_edges(image.EDGE_CANNY, threshold=(50, 80))

print("\nFrequency Scaling Test...")
for f in cpufreq.get_supported_frequencies():
    cpufreq.set_frequency(f)
    clock.reset()
    test_image_processing()
    freqs = cpufreq.get_current_frequencies()
    print("CPU Freq:%dMHz HCLK:%dMhz PCLK1:%dMhz PCLK2:%dMhz FPS:%.2f" %(freqs[0], freqs[1], freqs[2], freqs[3], clock.fps()))