[hpsdr] Pennylane drivelevel

[Phil Harman]

Hi Wully,

You appear to be on the right track. The Drive Level can vary from 0x00
(no power out) to 0xFF (max power out).

You only really need to set this each time the drive level is changed
since once set it will be saved in an FPGA register. However, most PC code
continually sends all the C&C bytes in round-robin fashion to cater for
dropped packets on the USB link.

Unlike Penny, for PennyLane the I and Q signals need to be held at full
scale at all times - we usually use AGC to do this.

You can monitor the level of your Q signal from the PC by connecting a
'scope to the output of the TLV320 on the DB25 connector. In this way you
can check that PennyLane is actually receiving your I and Q signals.

Hope that helps.

73 Phil...VK6APH






> ***** High Performance Software Defined Radio Discussion List *****
>
> Hi Phil
>
> I am trying to use the pennylane instead of the penelope. I am
> programming the interface by myself. For test purposes, I do the
> following: as soon as the TX-frequency is changed by the user program, I
> make the change and then I request the setting of the drivelevel by
> setting a logical txLevel_changed.
> In the next control-out seqence, I set C0 to 0x12, C1 to 0x80 (half
> power, just for Test), C2 to 0 (no micboost, mic selected)
> C3-C5 are all set to zero.
>
> But starting TX, I don't see any power out of pennylane.
>
> I have never programmed FPGAs up to now. I see
> in penelope.v the lines:
>
> wire [7:0] Drive_Level;     // Tx drive level
>
> NWire_rcv  #(.DATA_BITS(8), .ICLK_FREQ(122880000),
> .XCLK_FREQ(122880000), .SLOWEST_FREQ(1000))
>        p_ser (.irst(C122_rst), .iclk(C122_clk), .xrst(C122_rst),
> .xclk(C122_clk),
>               .xrcv_data(Drive_Level), .xrcv_rdy(drive_rdy),
> .xrcv_ack(drive_rdy), .din(C18));
>
> Is it correct, that this driveLevel is "stored" in the fpga, so that I
> don't have to repeat C0 at 0x12 to transmit?
>
>
> When I apply IQ-Values != 0 , I don't see output from pennylane. So I
> don't yet understand, how the current DriveLevel is treated in the
> pennylane.
>
> Any clarification is welcome.
>
> 73, Alfred
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