FTDI based USB serial devices appear to have a latency of 16ms under the MacOS included FTDI driver. I have unsuccessfully tried to reduce this latency via the below steps. Please let me know if you have additional suggestions.
1. Removed the Apple FTDI driver (AppleUSBFTDI.kext) and verified that it is no longer running from kextstat (and the FTDI device has disappeared from /dev/)
2. Installed the most recent MacOS VCP driver from FTDI (https://www.ftdichip.com/Drivers/VCP.htm)
3. Modified the configuration file in the VCP driver as detailed here below. Specifically, I have identified the Pmod USBUART in the config file as an "FTDI R Chip" based on its Vendor and Product IDs and, added the "ConfigData" key to that device, with a "LatencyTimer" key with value of 2 (ms). https://www.ftdichip.com/Support/Documents/TechnicalNotes/TN_105%20Adding%20Support%20for%20New%20FTDI%20Devices%20to%20Mac%20Driver.pdf
4. Loaded and tested the new driver.
After this, I still see reads come in every 16ms with all of the data from the last 16ms, instead of updated every ~2ms as I would have hoped. Please let me know if you have suggestions for fixing this problem! Thanks!
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jot
FTDI based USB serial devices appear to have a latency of 16ms under the MacOS included FTDI driver. I have unsuccessfully tried to reduce this latency via the below steps. Please let me know if you have additional suggestions.
1. Removed the Apple FTDI driver (AppleUSBFTDI.kext) and verified that it is no longer running from kextstat (and the FTDI device has disappeared from /dev/)
2. Installed the most recent MacOS VCP driver from FTDI (https://www.ftdichip.com/Drivers/VCP.htm)
3. Modified the configuration file in the VCP driver as detailed here below. Specifically, I have identified the Pmod USBUART in the config file as an "FTDI R Chip" based on its Vendor and Product IDs and, added the "ConfigData" key to that device, with a "LatencyTimer" key with value of 2 (ms). https://www.ftdichip.com/Support/Documents/TechnicalNotes/TN_105%20Adding%20Support%20for%20New%20FTDI%20Devices%20to%20Mac%20Driver.pdf
4. Loaded and tested the new driver.
After this, I still see reads come in every 16ms with all of the data from the last 16ms, instead of updated every ~2ms as I would have hoped. Please let me know if you have suggestions for fixing this problem! Thanks!
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