I have got the evaluation board for ADAR1000 and I was trying to generate PA_BIAS using the internal DAC, but not able to do so. I am interfacing the board with the software provided from you. I am following the below table from the datasheet:
I tried all the combinations described above in the GUI to generate some voltage on the pin 23 of connector P9A on the board which corresponds to PA_BIAS1. But I see nothing at all on the multimeter.
On the GUI, these are the steps I followed in order:
1. Connect to the board using ADDR0/1 = 0 (jumpers are left open)
2. Initialized TX on the tab "Tx Control"
3. Wrote some values to off and on registers shown below and enabled BIAS_CTRL
4. Enabled TX_EN under T/R Control tab
5. Checked the multimeter on pin23 of connector P9A, to see nothing.
I also tried with LNA_BIAS_OUT feature but also seeing no output voltage.
Am I missing something here?
I think I see what the problem is: by default the PA and LNA bias settings (among other settings) are being pulled from RAM (Please see the MEMORY ACCESS section in the datasheet). You need to tell the…
Are you still having trouble getting the PA and LNA bias pins to work properly?
Hi, sorry for delayed response. The current on 3.3V supply is 20mA and on the -5V supply its 10mA
And yes, its still not working.
I think I see what the problem is: by default the PA and LNA bias settings (among other settings) are being pulled from RAM (Please see the MEMORY ACCESS section in the datasheet). You need to tell the SPI to pull the data from the control registers. Set the Bias RAM Bypass bit to high to pull the bias data from the control registers. You can do this under the MISC tab in the GUI in the Memory Control section.
Yes, both the BEAM_RAM_BYPASS and the BIAS_RAM_BYPASS needed to be enabled in the GUI for the PA_BIAS to take values from the register. Thanks for your support, it worked.
After getting it to work with the eval board, I now am trying to interface the eval board with zynq fpga board. I have wired the SPI lines from the zynq board to the SPI lines on P3 connector of ADAR eval. I removed the SDP connector. Powered up the board. Then did the following sequence of reg writes:
(Please note that this below log is taken from the ADAR eval software, the sequcnce below shows how I got the PA_BIAS output working. Now, I do the same sequence of reg writes from the FPGA board, after restarting the board and disconnecting the SDP connector)
00:27:09: 00018 written to part00:27:09: 02F47 written to part00:27:09: 03142 written to part00:27:09: 03406 written to part00:27:09: 0363E written to part00:27:09: 03B40 written to part00:27:09: 01C7F written to part00:27:09: 02036 written to part00:27:09: 02136 written to part00:27:09: 02802 written to part00:27:09: 02800 written to part00:27:17: 03140 written to part00:27:24: 03040 written to part00:27:32: 02946 written to part00:27:32: 02A00 written to part00:27:32: 02B00 written to part00:27:32: 02C00 written to part00:27:32: 02D00 written to part00:27:36: 00000 written to part00:27:45: 03860 written to part
I have verified the SPI lines from FPGA using an oscilloscope and made sure all the housekeeping rules are followed like explained in this other post https://ez.analog.com/rf/f/q-a/103841/adar1000-eval-automated-control-via-spi/317562
I have also checked that the ADDR0/1 are stuck at 0. And the PA_EN GPIO is stuck at 0.
After doing all this, I would have expected to see the PA1_BIAS voltage change to 1.5V but it did not change. Maybe I missed something? Can you please help?