Category: Hardware
Product Number: AD9364
Hello,
We have been using the AD9364 for a number of years in a design based on the FMCOMMS board. Recently, we noticed that some units fail to lock at cold temperatures. I've boiled the problem down to a fairly simple set of steps:
1. Initial part with the ADI IIO driver.
2. Attempt to set the sampling frequency by using the command line interface:
echo 61440000 > /sys/devices/soc0/axi/e0006000.spi/spi_master/spi1/spi1.0/iio:device0/in_voltage_sampling_frequency
3. Check the error messages via dmesg, which reports the following:
ad9361 spi1.0: ad9361_dig_tune_delay: Tuning RX FAILED!
SAMPL CLK: 61440000 tuning: RX
0:1:2:3:4:5:6:7:8:9:a:b:c:d:e:f:
0:# # # # # # # # # # # # # # # #
1:# # # # # # # # # # # # # # # #
When this error occurs we do not get samples that we request over the IIO interface.
I have tried setting the charge pump current according to the information provided here: https://ez.analog.com/rf/wide-band-rf-transceivers/design-support/f/q-a/596266/how-to-debug-timing-calibration-fail-reg-0x6-in-cold-temperature
This made no difference that I can see. We are able to tune lower frequencies (below 57 MHz), but anything above that causes the error.
What else can I look at to figure out why we are having this issue? Some units do not appear to have the problem at all, but some consistently fail to tune the sampling clock.
-Dave
