Notecard I2C throughput


The Notecard documentation mentions the following regarding I2C data rate …

The Notecard operates the serial-over-I2C protocol at roughly 100kHz, in chunks of no more than 255 bytes, with a minimum 1ms delay between transactions.

Is there a maximum upper limit (in bytes) the Notecard will accept a continuous stream of data (in 255 byte chunks) as long as the 1ms delay is enforced?

regards, Rich …

Hey @richf,

You might find this section of the documentation helpful: Notecard Interfaces - Blues Developers.

If NOT using a Notecard firmware library, you may unintentionally send requests to the Notecard so fast that you overflow the 1500 byte buffer used to receive data (whether it be I2C, Serial, or UART). The solution is to pause 250 ms after every 250 bytes sent and ensure the total size of each NDJSON object sent is no more than 8KB.

Let me know if that helps. I’m going to do a little more digging into the limits of the Notecard this week and looking at how we can improve our existing documentation.