niconiconiMar 15
Optimizing IRQ latency on the STM32H743 @ 480 MHz, perhaps for NES ROM emulation... Best result so far: 100 nanoseconds input-to-output latency when the vector table and the IRQ handler are relocated to Tightly-Coupled Memory without making HAL calls. Not bad, but the GPIO controller (several buses away) looks like the real performance killer here. WARNING: buggy code, see correction https://mk.absturztau.be/notes/ajvb448y305b01i4. #electronics #STM32
Show threadRue Mohr
@niconiconi :]
I have a silly question. If you poll the emulation, can you get faster performance? Sometimes its faster to poll the low latency part and IRQ the rest.
Mar 15 at 11:51amWeb
Show threadniconiconiMar 15
@RueNahcMohr Yes, busy-polling is faster, limited only by the GPIO controller's clock and bus transaction latency.