Maximum speed of toggle of GPIO in STM32F0103 or STM32F746ZG

[Yshar.1]

i am having STM32F0103 discovery board and STM32F746ZG Nucleo. i want to check maximum speed on which i can toggle GPIO. When i select 48 MHz in STM32F0 i am getting maximum 1.25 uSec which is around 800 KHz Max.

in case of STM32F7 i am running at 216 MHz - then i am getting maximum .254 uSec, that is also very low as 4-5 MHz.

can any one sugget how get maximum speed of GPIO toggle. currently i am working on display panel.

Let me know if more clarity required. on this community few people asked same question but no body answered correctly.

[KnarfB]

How did you do your tests, register level using BSRR (Bit Set Reset Register) ?

[Yshar.1]

i have logic analyzer, i am toggling port using HAL_GPIO_TogglePin() API

[KnarfB]

while (1)
{
  GPIOB->BSRR = GPIO_BSRR_BS_3;
  GPIOB->BSRR = GPIO_BSRR_BR_3;
}

For LED on PB3 one loop takes about 166ns on my F042 @ 48Mhz at -O3 including the branch.

08000232:   movs    r2, #128        ; 0x80
08000234:   movs    r1, #8
08000236:   ldr     r3, [pc, #8]    ; (0x8000240 <main+32>)
08000238:   lsls    r2, r2, #12
0800023a:   str     r1, [r3, #24]
0800023c:   str     r2, [r3, #24]
0800023e:   b.n     0x800023a <main+26>

[Piranha · Accepted solution]

It's simple - using HAL and talking about maximum speed, minimum size or stability is just nonsense.

[Yshar.1]

thanks, i will check this and update.:D

[Yshar.1]

Thanks:smiling_face_with_smiling_eyes:

[waclawek.jan]

@KnarfB​ ,

where's the loop targer in that disasm? Why are there odd address labels there?

Sorry for the OT.

JW

[KnarfB]

Thanks for spotting that. Sometimes the disasm shows garbage, blame STM32CubeIDE for it. Corrected.