PGA460: No response to uart query

Hi Fred,

What is the value of VPWR? The PGA460 requires 6-28V to operate correctly. A 5V USB based supply will not be sufficient enough to power the PGA460.

At what logic level is your master operating (3.3 or 5V)? By the default, the PGA460 operates at 3.3V logic levels. If you need to use 5V, then a 100kOhm pull-up resistor to 3.3 or 5V must be placed on the TEST pin.

To check if your UART port is correctly communicating with the PGA460, send a basic command, such as a register read command. Here is an example master transmit sequence in hex: {55 09 1B DB}
where:
•09 is the register read command and addr 0
•2B is the register address to read EE_CRC (usually returns a non-zero value)
•CB is the checksum for this transmit sequence

The PGA460 should return three values when using this command:
•Diagnostic field (0x40) if master transmit was successful
•Register address value
•PGA460 generated checksum

Note that the PGA460 UART frame is not completely standard, since the PGA460 requires two-stop bits. Be sure you have configured your master's UART port for two-stop bits, rather than the default one-stop bit. I would recommend you run with a baud rate of 9600 for initial testing. Though using a single-stop bit is not recommended in the long-term, a baud rate of 9600 works with one-stop bit when using Energia or Arudino.
The PGA460 supports a baud rate between 2.4k-115.2kBaud. What baud rate are you using?

The threshold must be written to at least once after start-up to clear the threshold CRC error that is always flagged high on initialization. The threshold CRC error must be cleared before the PGA460-Q1 is allowed to execute a Burst & Listen or Listen-Only command. However, you are able to read and write to all device registers without clearing the THR_CRC_ERR.

VPWR is 10 volts
My arduiono nano logic level is 5V
I have tied TEST directly to 5V on nano, not through pulp resistor
Earlier I was getting a result when sending a read register command, now has stopped working.

My breadboard

Waveform on pga460 RxD, pin 11.

This was once working. I have two identical adapter boards with pga460, both behave same way. Feels like there must be some initialization that I'm not doing. Are there any undocumented startup states? How does pga460 know which comm scheme to use. I'm assuming async part.