Is 400kbps(51200 bytes/seconds) the high speed of i2c on nrf52832?

RE: Is 400kbps(51200 bytes/seconds) the high speed of i2c on nrf52832?

Turbo J — Sat, 25 Jan 2020 12:35:13 GMT

Back to the drawing board.. for new component selection.

Choose a parallel DAC and either FPGA or high power µC (think 600MHz i.MX here for example). Only those can supply the DAC with data fast enough - via DMA to GPIO pins.

NRF chips do not have a DMA-to-GPIO mode AFAIK. You can still use the NRF chip for BT LE or other 2.4GHz radio stuff.

RE: Is 400kbps(51200 bytes/seconds) the high speed of i2c on nrf52832?

min_yuan — Sat, 25 Jan 2020 02:29:33 GMT

I'm new to embedded development, no idea which way can post a high speed DAC output, e.g 9 times/us, thanks!

RE: Is 400kbps(51200 bytes/seconds) the high speed of i2c on nrf52832?

min_yuan — Sat, 25 Jan 2020 02:21:34 GMT

Hi Turbo,

Thanks for you quick reply! The other end of the bus is MCP4725, every voltage output need 3 bytes, so in the max speed(400 kbps), only can change the voltage of the DAC about 17066 times/second. I want to post voltage change call 9 times/us

RE: Is 400kbps(51200 bytes/seconds) the high speed of i2c on nrf52832?

Turbo J — Fri, 24 Jan 2020 19:12:40 GMT

What hardware is on the other end of the bus?

I2C requires much more complex fast mode plus tranceivers for >400kHz - I've seen these mostly on NXP chips. Basically the pullup resistors cannot pull the bus fast enough from 0 to 1.

Faster SPI is available on the NRF52840 - but be sure to check the errata.