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softerhardware / Hermes-Lite2

A second generation low-cost amateur HF software defined radio transceiver.
http://www.hermeslite.com
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Hardware: Make sure stuff is disabled during FPGA configuration #22

Closed in3otd closed 7 years ago

in3otd commented 7 years ago

In the H-L v2b2 the TX relay toggles at power-up, while the FPGA is being configured. Similarly, the bias source for the PA, U14, is briefly enabled. May not be harmful but would be good to add a pull down (as R125, which should likely be mounted by default). I find the relay clicking a bit annoying because it makes the user think that the unit went into TX unexpectedly.

in3otd commented 7 years ago

I may have missed something but why did you move this to "Firmware"? My understanding was that you cannot control the pin status during configuration - the docs say "The user I/O pins and dual-purpose I/O pins have weak pull-up resistors, which are always enabled (after POR) before and during configuration".

softerhardware commented 7 years ago

Yes, you are right. I didn't pay close attention when reading this initially. There are also some sequencing changes that need to be made in the firmware.

softerhardware commented 7 years ago

Resistors R124, R125, R126 added to beta3 schematic.

softerhardware commented 7 years ago

Done on PCB.