| Main index | Section 4 | Options |
The PWM hardware is controlled via the sysctl(8) interface:
dev.pwm.0.mode: 1 dev.pwm.0.mode2: 1 dev.pwm.0.freq: 125000000 dev.pwm.0.ratio: 2500 dev.pwm.0.ratio2: 2500 dev.pwm.0.period: 10000 dev.pwm.0.period2: 10000 dev.pwm.0.pwm_freq: 12500 dev.pwm.0.pwm_freq2: 12500
| dev.pwm.0.mode, dev.pwm.0.mode2 | |
|
PWM Mode for channels 1 and 2.
Three modes exist, 0=off, 1=PWM, 2=N/M.
The N/M mode is a first order delta-sigma mode, which makes a quite
handy DAC output with a trivial RC lowpass filter.
| |
| dev.pwm.0.freq | |
| The input frequency to the PWM hardware in Hz. Applies to both channels 1 and 2. Minimum frequency is 123 kHz, maximum frequency is 125 MHz. | |
| dev.pwm.0.period, dev.pwm.0.period2 | |
| The period length in cycles. In PWM mode, the output frequencies will be ( dev.pwm.0.freq / dev.pwm.period ) and ( dev.pwm.0.freq2 / dev.pwm.0.period2 ). In N/M mode this is the 'M'. | |
| dev.pwm.0.ratio, dev.pwm.0.ratio2 | |
| The "on" period in cycles for PWM channels 1 and 2. In PWM mode, to get a 25% dutycycle, set this to 25% of dev.pwm.0.period or dev.pwm.0.period2, as appropriate. In N/M mode this is the 'N'. | |
| dev.pwm.0.pwm_freq, dev.pwm.0.pwm_freq2 | |
| The calculated PWM output frequencies in PWM mode, for channels 1 and 2. | |
| BCM283X_PWM (4) | September 10, 2018 |
| Main index | Section 4 | Options |
Please direct any comments about this manual page service to Ben Bullock. Privacy policy.
