RM42L432: HET setting

Hello Susan,

The maximum HCK for RM42Lx is 100MHz. 

1. Theoretically, the minimum loop period (LRP) is 10ns. HR clock = VCLK2/hr=80MHz if hr=1. LR clock = HR clock/lr = 100MHz if lr=1. Since the longest path through an NeHET program must be completed within the loop resolution clock (LRP). Otherwise, the program will execute unpredictably because some instructions will not executed each time through the loop.

     ts=hr*lr is the time slots (cycles) available for instruction execution per LRP. 

Generating a simple PWM uses 2~3 instruction, this means ts=4 is fine to execute 2 instructions (cnt, and ecmp). LRP=hr*lr*VCLK2 period = 4*VCLK2 period = 40ns

The maximum PWM frequency: 12.5MHz (period = 2*LRP=80ns).

2. As I said,  the longest path through an NeHET program must be completed within the loop resolution clock (LRP). Otherwise, the program will execute unpredictably because some instructions will not executed each time through the loop.

If LRP=160ns, ts=16. How many instructions in your code for PWM and capture? If your code takes more than 16 cycles, some code will not be executed.

thank you for your reply

But I can't  generat  any PWM when the  LR clock is 100MHz.、50MHz。Until  LR clock less than 25MHZ can  generat PWM。