Custom USB Dongle with In-Field-Programming, USB-HID, DFU OTA

[bvrm]

We want to design our own custom USB Dongle for connecting our sensor board to a PC. Sensor board has a nRF51 chip using Gazell protocol to transmit sensor data and also softdevice S110 with bootloader for DFU OTA.

Custom Dongle could be a single chip design (nRF24LU1+) or dual chip design with nRF51 wireless connectivity chip and USB connectivity chip (like the segger).

Custom USB Dongle should support:

1. In-Field-Programming from PC for the wireless connectivity chip

2. USB-HID-Transfer of sensor data to PC

3. DFU OTA from PC for the sensor board nRF51 chip

Segger chip does not support #2. nRF24LU1+ does not support #3. FTDI USB chips do not support #1 and #3.

Any idea for a USB-Bridge Chip which supports all 3 requirements?

[Baruch]

I believe that the nRF24LU1+ is all you need, you can have a bootloader on it to be able to upgrade it in the field through USB. You'll also need a bootloader on the nRF51 to allow for OTA upgrade and the USB HID transfer will work for you too, you will need to write your own firmware for the nRF24LU1+ to do it but it shouldn't be too hard.

Though I have to admit I didn't try that myself yet.

[David Edwin]

I do agree that the nRF24LU1 seems to be the more appropriate solution as all 3 seem to be implementable on the nRF24LU1. The nRF24LU1 ships from the factory with a built-in bootloader, you can look at nAN-18 for wireless firmware update between the nRF24LE1 and nRF24LU1.