Trying to understand the cycle count on my STM32G431 code Hi,
I have some code running on an STM32G431 that does a loop in which it reads on a pin on port GPIOB, shifts the value and writes the result on GPIOC.
I have trouble really understanding the timing I see on the oscilloscope.
The code is:
ldr r1, =0x48000410
ldr r2, =0x48000814
1:
ldr r3, [r1]
lsl r4, r3, #3
str r4, [r2]
b 1b
the delay between the signal going changing on B1 and the signal changing on C4 is between 40 and 80ns depending on when the change occurs during the loop. If I made no mistake, both the SYSCLK and HCLK run at 170MHz:
let mut d: embassy_stm32::Config = Default::default();
d.rcc.hsi = false;
d.rcc.hse = Some(Hse { freq: Hertz::mhz(8), mode: HseMode::Oscillator });
d.rcc.pll = Some(
Pll {
source: PllSource::HSE, // 8MHz
prediv: PllPreDiv::DIV2, // 4MHz (min: 2.065MHz, max: 16MHz)
mul: PllMul::MUL85, // 340MHz (max allowed: 344MHz)
divp: None,
divq: None,
divr: Some(PllRDiv::DIV2), // 170MHz (max allowed: 170MHz)
}
);
d.rcc
