CRC ERROR nrf5340

RE: CRC ERROR nrf5340

ketiljo — Tue, 22 Sep 2020 09:55:24 GMT

The crystal you have is a 8 pF crystal (CL value). So the load caps should be 12 pF.

Ccap = CL * 2 -Cpin, where Cpin = 4 pF.

Given that it works with a generator, your crystal is probably not loaded correctly. This will pull the frequency and affect the radio.

RE: CRC ERROR nrf5340

emag nioj — Sat, 19 Sep 2020 04:39:07 GMT

Hi Ketiljo, sorry to bother again. I reworked the custom board but i have always crc error troubles. Also other prototype boards are with same problem. Enabling the internal 8pF internal capacitors it seems a bit better but very random.

Connecting an external 32MHz signal from a generator one board started to work very well, but another one nope. The crystal is diigkey 1253-1586-1-ND

Please Let me know where i can put the schematic possibly in a private way.

Many thanks,
Emag

RE: CRC ERROR nrf5340

emag nioj — Thu, 17 Sep 2020 09:14:17 GMT

Thank you, i m trying to rework the prototype pcb connecting the E31 and preparing a new gerber..

Many thanks!

RE: CRC ERROR nrf5340

ketiljo — Thu, 17 Sep 2020 08:52:21 GMT

All the VDD pins are internally connected. But the connection on the die isn't strong enough to properly power the device completely. So the VDD supply are split into different pins. So one pin doesn't power a specific part of the device. You need to connect the PS to all VDD for proper operation.

Most likely, there are parts of the radio power supply that are operating out of spec when you are missing power on pin E31.

RE: CRC ERROR nrf5340

emag nioj — Wed, 16 Sep 2020 12:50:42 GMT

Hello, pin E31 VDD 1.8V is not connected there is a fault in the PCB. I m trying to rework.

on the PDK i have removed the track that connects E31 to the capacitor and the PDK started to have the same troubles.

if possible please confirm that a missing VDD on E31 can be the reason of CRC errors the other functionalities on the CPU are all ok.

if E31 is the power supply of the internal oscillator, can i replace the external xtal with a 32MHz oscillator? it's only a prototype but i need it for my customer.

Thank you!
Emag

RE: CRC ERROR nrf5340

ketiljo — Wed, 16 Sep 2020 11:17:58 GMT

Can you post a schematic and the 32 MHz crystal spec please?