F28335 GPIO OUTPUT PLUS PROBLEM

user4287139

Other Parts Discussed in Thread: CONTROLSUITE

Hi~

Recently i used the pin GPIO33 of F28335 to send a plus, the program copied from controlSUITE gpio_setup.c and add simple line :

while(1){

GpioDataRegs.GPBSET.bit.GPIO33=1;

GpioDataRegs.GPBCLEAR.bit.GPIO33 =1;

}

I configed the clock of CPU had up to 150Mhz and the plus width should be 6.67ns*2 per cycle, while through my oscilloscope it's about 100ns per cycle, has somebody meet similar problem or just give me some suggestions?

Thanks！

over 11 years ago

0 Gautam Iyer over 11 years ago

Guru 192875 points

Hi,

GPIO toggling has timing limitations. Please check this link:

Regards,

Gautam

0 user4287139 over 11 years ago in reply to Gautam Iyer

Prodigy 30 points

Thanks a lot! It does work when use register defdine .all instead of .bit. But it's a pity that when i want to transfer some data between the toggle it still spend 200ns, any good idea to solve this problem?

0 Gautam Iyer over 11 years ago in reply to user4287139

Guru 192875 points

Can you describe in detail - what are you planning to achieve? I'm unable to understand with your above explanation.

0 user4287139 over 11 years ago in reply to Gautam Iyer

Prodigy 30 points

i need to reveive one byte data every time when the signal line RD# is low and then pull it up ,while the cycle of RD# line is the less the better(the largest is 160ns ), now "line high+transfer data+ line low" cost about 200ns. i had try to use epwm but it's hard to monitor , any good ideas? Thanks for your patience~

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F28335 GPIO OUTPUT PLUS PROBLEM