topic S32K I/O SPEED too slow in S32K

S32K I/O SPEED too slow

zhengjianfei — Fri, 10 Aug 2018 03:54:39 GMT

HELLO，Recently I discovered S32K's IO speed is not as fast as i wish。The CPU frq is 112Mhz，bus frq is 56Mhz。The IO speed is 130ns，that is 7.7MHZ。I was not use SDK but directly write the register PDOR.As usually, IO Speed can reach the half of Bus frq.That is when bus frq is 56MHZ,io speed can reach 26Mhz.But S32K's is just 7.7MHz.Can S32K's io speed faster?

Re: S32K I/O SPEED too slow

danielmartynek — Thu, 16 Aug 2018 10:53:33 GMT

Hello,

Could you please tell me the use case of such an implementation? If you want to generate a PWM signal or toggle GPIO for some timing purposes, you can use hardware peripherals.

There are many variables that influence the frequency. Number of instructions, prefetching, wait states on crossbar switch...

Regards,

Daniel

Re: S32K I/O SPEED too slow

zhengjianfei — Fri, 17 Aug 2018 01:31:51 GMT

I use GPIO to drive a 16bit LCD。So I need GPIO as fast as it can。

Re: S32K I/O SPEED too slow

danielmartynek — Fri, 17 Aug 2018 10:54:04 GMT

Hello,

I think you can get better results with LMEM Cache:

LMEM->PCCCR = 0x85000001;

Regards,

Daniel