Version 5 (modified by 7 years ago) (diff) | ,
---|
This serves as a log of attempts to debug the 4 Channel ADC prototype board.
Clock Replacement
- Date
- 20 Jul
- Attempted fix
- Replace erroneous CMOS clock used on board with LVDS alternative.
- Method
- Remove on-board clock, connect waveform generator to pads and simulate 100MHz LVDS signal.
- Result
- Upon power up, the outbound differential pairs began transmitting.
Current Draw
- Date
- 20 Jul
- Attempted fix
- Use digital multimeter to measure current draw when the configuration
RESET
pin is brought high then low. - Method
- One multimeter was used in series with the power supply to measure current draw, while a second one was used to confirm the voltage on the
RESET
pin was changed. - Result
- Upon reset, there was no change in current when
RESET
was toggled.
Parallel Configuration Pins
- Date
- 19 Jul
- Attempted fix
- Use parallel config instead of serial config, in case the issue lies with the serial configuration method.
- Method
RESET
is tied HIGH,CFG1
andCFG2
are tied HIGH,SCLK
andSDATA
are tied LOW, andSEN
is tied HIGH. The board was supplied 12V from an adjustable power supply.- Result
- Upon power up, the outbound differential pairs reported 0V relative to ground.
Config Pin Startup Behavior Adjustment
- Date
- 18 Jul
- Attempted fix
- Change
SCLK
andSDATA
so they default to HIGH when not in use, as reflected on the ADC datasheet. - Method
- The change was implemented and firmware was re-synthesized.
- Result
- Upon power up,
SCLK
andSDATA
were HIGH when not in use, but the outbound differential pairs reported 0V relative to ground.
SCLK
Timing Adjustment
- Date
- 17 Jul
- Attempted fix
- Change the behavior of
SCLK
to become active only when writing register data to the ADC, instead ofSCLK
being active all the time. - Method
- The change was implemented and firmware was re-synthesized.
- Result
- Upon power up,
SCLK
was only active when writing register data, but the outbound differential pairs reported 0V relative to ground.
Inductor Replacement
- Date
- 14 Jul
- Attempted fix
- Replace the inductor on the bottom of the board with a 1A fuse.
- Method
- The inductor was removed and a 1A fuse was substituted in its place.
- Result
- Upon power up, the fuse remained intact, but the outbound differential pairs reported 0V relative to ground.
Config Pin Breakout
- Date
- 11 Jul
- Attempted fix
- Move
SCLK
,SDATA
,SEN
, andRESET
off the FMC Connector and to a PMOD (JZ1
-4
) so that config signals can be transmitted at 3.3V instead of 1.8V. - Method
- The change was implemented and firmware was re-synthesized.
- Result
- Upon power up, register data could be read from the PMOD Connector, but the outbound differential pairs reported 0V relative to ground.