Using BLE with three & four pin PA/LNA frontend?

RE: Using BLE with three & four pin PA/LNA frontend?

Andreas — Tue, 24 Nov 2020 07:33:16 GMT

Hi,

OK, I see. With this control specification, if you are not able to fork the TXEN/RXEN PPI channels to a GPIOTE you could look into using Radio Notification signals and set the necessary pins ahead of the radio activity. The Softdevice processing may happen at any time, I would be more confident in using this than firing an interrupt off PPI, hopefully the extra few µA for some µs is acceptable given that you run a PA in the first place.

Best regards,
Andreas

RE: Using BLE with three & four pin PA/LNA frontend?

SebastianA — Mon, 23 Nov 2020 13:48:10 GMT

Hi!

We are using Skyworks SE2431L, but we also sell a library with our networking protocol that our customers use with different FEMs. They configure our library with a list of up to four pins and the wanted signal levels for the different modes of operation.

Our library comes in two flavors, one with and one without softdevice support. We would like both variants to have the same features to make it easier for the customers to start using softdevice.

I'll have to see if we have enough PPIs and GPIOTE channels left to support three pins this way.

Would it be possible to let the forked PPI trigger a quick interrupt or can the CPU be busy at prio 0 when the PPI is triggered?

BR,
Sebastian

RE: Using BLE with three & four pin PA/LNA frontend?

Andreas — Mon, 23 Nov 2020 13:21:42 GMT

Hi,

As you say the Softdevice toggles two pins, TXEN and RXEN. If you need to control more pins, you need to do this manually in your application. You can fork out other pins, but there is no guarantee this is a feasible solution for the FEM you plan to use, you will have to study the control logic described in the datasheet.

Not sure I have seen any parts that strictly require 3 or4 control lines, which part are you planning to use?

Best regards,
Andreas