Forum Discussion
ContributorIncrease frequency of HPSGPIO
Hi snehal_p,
I try to check further regarding the gpio limitation on arm cortex a9 for the HPS.
It shows that:
"The PL061 PrimeCell General Purpose Input/Output (GPIO) is an AMBA compliant SoC peripheral that is developed, tested, and licensed by ARM Limited. Use the GPIO to generate or detect low frequency signals (less than 1MHz)."
It seems that the frequency you are capable of generating also meet around that range due to the limitation of the GPIO regardless of the instruction cycles which involves in the gpio toggling operation.
Thanks.
Regards,
Aik Eu
Regular ContributorHi snehal_p,
If I am correct for the below:
It seems that each time you write the 8 bit data to the shift register, you will trigger a clock signal(DISP_HMI_CLK) to let the shift register for acknowlege a single bit of data at the data line of the shift register.
The clock is generated based on how the code is written in instruction sequence considering the time taken for the function to perform the shift operation.
May I know is the shift operation eventually able to display the logo image from the code without issue?
If no issue what is the problem that you are observing from the operation to have image display on the LCD?
May I know how you get to measure the clock signal in the first place?
I suggest to tap the clock signal of the shift register wher you can observe the time take for 8 bit data transfer to the shift register
I cant tell how fast is the clock signal from the code itself. If the current clock frequency is too high, higher than the expected 900khz which you prefer to have, then you can put delay in the between instruction to fine tune it.
Thanks.
Regards,
Aik Eu
ContributorHello Aik Eu,
Yes we are able to get images on display.
We have a requirement of higher frequency so it will provide higher fps.
We measured the clock frequency by probing the DISP_HMI_CLK on oscilloscope.
900khz is one cycle of 1bit data on disp-hmi-clk, we need to increase it to 10MHz.
PFA hps clock setting.
Thanks,
snehal_p
