What is the maximum number of PWM channels for nRF51-DK with SoftDevice running?

[Mahesh Venkitachalam]

Since the SoftDevice uses Timer0, am I correct in assuming that the maximum number of PWM channels for nRF51-DK with SoftDevice running is 4? (Two each on Timer1 and Timer2.)

Thanks

[Nick]

TIMER1 and TIMER2 each have 4 capture/compare channels that can be wired up to output pins using the GPIOTE/PPI blocks. That gives a total of 8 potential PWM outputs on the TIMER modules.

[Mahesh Venkitachalam]

The docs for PWM library say "Up to three independent PWM instances. Two PWM output channels per instance." - so if Timer0 is reserved, how can I set up 8 PWM outputs using app_pwm_init()? Call I call APP_PWM_DEFAULT_CONFIG_2CH twice each for PWM1 and PWM2? Thanks

[Øyvind Karlsen]

Hi,

You can have a maximum of 4 PWM channels, this is because we have 4 GPIOTE channels.

Nick is correct that in theory we could have 8 due to the timers having 4 compare events, however you typically will need one of those compare events to do a reset, so we end up with a theoretical max of 6.

Best regards,

Øyvind