Peeking at Espruino Board Timers 2, 3, 4, and 5

Experiments with timers:
Experiment 1:
Setup A0 at 50hz, Duty cycle 20%
Setup A1 at 50hz, Duty cycle 40%
Setup A2 at 50hz, Duty cycle 60%
Setup A3 at 50hz, Duty cycle 80%
Using isTimerEnabled3.js modify lines 168..172

analogWrite(A0,0.2,{ freq : 50 }); 
analogWrite(A1,0.4,{ freq : 50 }); 
analogWrite(A2,0.6,{ freq : 50 }); 
analogWrite(A3,0.8,{ freq : 50 });
Results:
Timer 5 Enabled
CR1=81
CR2=0
SMCR=0
DIER=0
SR=f
EGR=0
CCMR1=6868
CCMR2=6868
CCER=1111
CNT=d9ba
PSC=15
ARR=ffae
CCR1=3322
CCR2=6645
CCR3=9968
CCR4=cc8b
DCR0
DMAR=81

Confirm with scope on pins A0, A1, A2, and A3.
All outputs are 50 Hz.
A0 duty cycle is 20%, A1 duty cycle is 40%, A2 duty cycle is 60%, A3 duty cycle is 80%
Modify the A3 line and change the frequency to 10 hz

analogWrite(A0,0.2,{ freq : 50 }); 
analogWrite(A1,0.4,{ freq : 50 }); 
analogWrite(A2,0.6,{ freq : 50 }); 
analogWrite(A3,0.8,{ freq : 10 });
Results:
Timer 5 Enabled
CR1=81
CR2=0
SMCR=0
DIER=0
SR=11
EGR=0
CCMR1=6868
CCMR2=6868
CCER=1111
CNT=28fd
PSC=6d
ARR=ffae
CCR1=3322
CCR2=6645
CCR3=9968
CCR4=cc8b
DCR0
DMAR=81

Use scope on pins A0, A1, A2, and A3 to check frequency and duty cycle.
All outputs are 10 Hz.
A0 duty cycle is 20%, A1 duty cycle is 40%, A2 duty cycle is 60%, A3 duty cycle is 80%
Timer 5 values differ in the PSC registers for each case.
PSC at 10Hz is x6d, PSC at 50Hz is 0x15, converting to decimal give 109 and 21.
109/21 ~= 5

Design consideration:
If you need PWM outputs with different frequencies, you will need to select pins that use different timers for different frequencies.