HackRF
23.5 USB
Would support for host mode on the second USB PHY be useful somehow? This is only possible with a larger LPC43xx
package that exposes the second PHY’s ULPI signals. Unless, of course, a mere full-speed PHY is acceptable.
23.6 Power Management
The MAX5864 appears to come up in “Tx” or “Rcvr” mode – I have observed that the part will pass DA bus data
to ID/QD without any SPI configuration. If we’re worried about USB power and minimizing current consumption, it
might be good to have this device on a power regulator with an ENABLE pin, or have a FET power switch. Yes, let’s
add a high side switch for the whole RF section.
23.7 Regulators
U21 (the TPS62410) FB1 pin is connected on the far side of jumper P8 (VCC), which puts the jumper inside the
feedback path. If the jumper trace is cut, the regulator may go nuts because the FB pin is floating.
23.8 Buttons
Add a reset button (for the LPC43xx). Maybe add a DFU button too.
23.9 Shielding
Maybe add a can around the RF section.
23.10 Footprints
Tighten up holes for USB connector support legs to improve placement consistency. Make some of the QFN pads
bigger (especially on the RF switches) for better soldering.
86 Chapter 23. Future Hardware Modifications
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