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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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Envelope PWM code update #117

Closed in3otd closed 5 years ago

in3otd commented 5 years ago

Some small updates to the TX envelope PWM code: one is to solve the synchronization issue mentioned here, by increasing the EER_req width to 4 clock cycles. In theory it should be possible to use clk_2x for the EER interpolation FIR and reduce the EER_req width to 2 but I quickly tried and it didn't work, probably because timing would need some adjustment.

As before, to enable the PWM code, hermeslite.v should be modified to set LRDATA=2 and NR=3.

I wondered if the EER-enabled gateware creation could be automated via the Makefile but I'm not so familiar with that, so I'll leave that for later...

in3otd commented 5 years ago

I've rebased on the latest commit and checked that make still complies the various revisions. A quick check on my H-Lv2b8 with linhpsdr shows the expect PWM output. As discussed offline, I'll merge this PR then.