SM6FBQ / HackRF clone - History

HackRF One: swap pins for platform detection

- move EN_1V8 to P5_0, U23 pin 37
- move !VAA_ENABLE to P6_10, U23 pin 100
- move !RX_AMP_PWR back to P2_12, U23 pin 106

Platform detection is now performed using P5_0 and P6_10 which avoids
the complication of having to detect a pull-up to VAA which may not yet
be switched on.

HackRF One: update hardware detection pin straps

Additionally swap:
- EN_1V8, P6_10, U23 pin 100 (pull-down)
- !RX_AMP_PWR, P2_12, U23 pin 106 (pull-up)

Detecting which has the pull-up and which has the pull-down enables
version detection that may be more reliable than the ADC method.

HackRF One: change U19 from Si5351C to Si5351A

add clock distribution and detection