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Hi,
I noticed on another post that on old WARPLab designs (for WARP V3), the PA was turned on via a C function call and could thus be disabled in the firmware. I've been looking around WARPLab7, and could not find a similar function. Does one exist or, if I wanted to disable the PA, would I have to do it in the hardware design?
Also, it wasn't clear from the PA spec sheet, but would disabling the PA ground (or float) the RF output or would it pass the non-amplified signal (from the MAX chip) through?
Best,
Abeer
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The PAs are controlled from the radio_controller core HDL. The radio_controller implements a simple state machine to sequence the enabling of the MAX2829 Tx, PA, MAX2829 VGA and PHY. The core enables either the 2.4 or 5GHz PA when this state machine asserts the PAEn signal.
The sequencing is configured from software via the radio_controller_setTxDelays(ba, dly_GainRamp, dly_PA, dly_TX, dly_PHY) macro, where each dly_ value is a number in [0,255] that sets the number of clock ticks before each output is asserted. The value 255 is special and will disable the corresponding output.
The radio_controller driver calls radio_controller_setTxDelays(ba, 150, 0, 0, 250) during init. WARPLab does not override this by default. To disable the PAs in WARPLab, add radio_controller_setTxDelays(ba, 150, 255, 0, 250) after radio_controller_init() in wl_interface.c.
Also, it wasn't clear from the PA spec sheet, but would disabling the PA ground (or float) the RF output or would it pass the non-amplified signal (from the MAX chip) through?
I believe this is true, but I can't remember ever testing it. I would guess the disabled PA would attenuate the signal a bit, so the output will probably be weaker than the (normal Tx power) - (PA gain).
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