reserve the interface for interrupt & DMA

[Happiness-in-Danger]

I want to run auto-signal like DShot. I will write C program and debug in firmware. In micro python I can import it and use my program .
but I can't use interrupt & DMA ,because there are some errors. So I wish there are some interfaces I can use for my program. Thanks

[Josverl]

Why use a separate C module at all ?
AFAIKT it is hardly needed for speed of the CRC calculation. That could be just as well done in MicroPython, viper or native for the common Baud rates

import micropython
def dshot_crc_py(packet12):
    # packet12 = 12-bit payload
    return (packet12 ^ (packet12 >> 4) ^ (packet12 >> 8)) & 0x0F

# or faster versions :
@micropython.native
def dshot_crc_native(packet12):
    return (packet12 ^ (packet12 >> 4) ^ (packet12 >> 8)) & 0x0F

@micropython.viper
def dshot_crc_viper(packet12: int) -> int:
    return (packet12 ^ (packet12 >> 4) ^ (packet12 >> 8)) & 0x0F

dshot_crc = dshot_crc_viper  # choose the fastest version for your platform

def make_dshot_frame(throttle, telemetry=0):
    payload = (throttle << 1) | telemetry
    crc = dshot_crc(payload)
    return (payload << 4) | crc

for t in range(0, 2048, 27):
    frame = make_dshot_frame(t)
    print(f"throttle={frame >> 5:b012} telemetry={(frame >> 4) & 1} crc={frame & 0x0F}")

Not sure if I have used the correct CRC4 calculation, please verify
Then you could send it using the standard RMT, SPI or rp2.PIO depending on the rest of your architecture, most of which support DMA to offload

[Happiness-in-Danger]

Not for CRC, it's for how to auto-send and cpu can't join in this process.Because on micro python level ,I need to collect date from sensors control motor and read datas from motor.All of these new carried out simultaneously

[Josverl]

So based on the very limited information you have provided

it's for how to auto-send and cpu can't join in this process.

You will need to look into DMA and either a MCU standard SPI or a custom rp2.PIO to send that data.
for the integration options of MicroPython and C, I suggest the two most relevant options are:

• Dynamic loadable Native Modules
• Static linked external C modules

Each have their pros and cons

To assist you further it would be helpful if you can provide:

• the MCU platform are you using,
• the high level architecture / split of what you want to to in MicroPython / C
• at least basic information on "some interfaces I can use"
• the number of of motors to control (simultaneously - 4-ish ?)
• how you plan to generate / make the speed controls available

[Happiness-in-Danger]

Sorry, work is very busy.

1. the MCU platform are you using,
   --STM32H series
2. the high level architecture / split of what you want to to in MicroPython / C
   --if the function can be implemented in Micropython I will use it. However some function have latency requirements, it must use C
3. at least basic information on "some interfaces I can use"
   --sorry my mistake it's IRQ Handler. I find all time IRQHandlers have registered. I can't use IRQHandlers like TIM2_IRQHandlers in my C model. So I wish there are somethings like API let me call it or IRQHandlers manager allow me register it.
4. the number of of motors to control (simultaneously - 4-ish ?)
   --yes , I find there are 4 channel in one time.
5. how you plan to generate / make the speed controls available
   --sorry I don't know what the speed is for. if it's motor. the DShot is standard ,I don't care it . but I just control time interval of the signal

[Josverl]

Apologies,

I do not understand what you are trying to do, and therefore cannot help you further.