cl- Posted July 19, 2019 at 01:35 PM Share Posted July 19, 2019 at 01:35 PM First of all, I love the HAT Brick! Thanks! I have a general question related to its performance: Do you know whether there are technical limits on how much data I can get through the GPIO of the Raspberry Pi? I'm using the new Version 4 Raspberry Pi (2 GB RAM) and the HAT Brick. I tried to get the full rate of 25.6kHz out of an Accelerometer V2 bricklet, but it wasn't possible. It seems strange to me, as the Master Brick has no problems at all (at least when connecting only one Accelerometer V2 with continuous acceleration callback). I know about the technical limits for more than one Accelerometer V2 bricklet. When compared to the Master Brick, however, the data throughput with the HAT brick seems to be much lower. I was expecting it to be the other way around (as there isn't a USB connection anymore that limits the number of messages per second). Is there a technical reason why the HAT Brick doesn't get the (at least equal) amount of data through the system that is needed for the Accelerometer V2 bricklets? How does Debian (or Brick Daemon on the Pi) read the GPIO? I'm guessing it iterates over the SPI pins one by one? For comparison: I connected a Master Brick to the Raspberry Pi and it gave me the expected "Master Brick" like performance I was used to in the past. Thanks for your support! EDIT 1: I'm using your Rust API bindings. EDIT 2: Does it have to do with the maximal SPI clock of 1400000? // On RPi 3 make sure to set "core_freq=250" in /boot/config.txt. // The SPI clock is scaled with the variable core_freq otherwise // and the SPI clock is not stable... #define BRICKLET_STACK_SPI_CONFIG_MAX_SPEED_HZ 1400000 Quote Link to comment Share on other sites More sharing options...
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