I am using KC705 with AD9364 carte de evaluation and Vivado 2013.4 on 64bit windows based PC with current version of noOS driver.
I want to test the vout of auxDAC1 and auxDAC2 for different Vref(0 to 3) as given in the Figure 51. of UG673 (ref. manual aD9364).
Because, I have to generate some precise voltages for Power Amplifier further.
when I set to produce different voltages from init parameters in main.c, it produces the nearby values but the problem is both auxdac1 and auxdac2 produces different voltages.
for example if I want to produce 300 mv
auxDAC1 produces 309.3 and auxDAC2 produces 296.9
Which is always the case. I performed a litte test with several ranges which is attached herewith.
I check the values using a multimeter on the given test points near the RXA RF port.
I found that the calculation to write the correct value is done in ad9361.c ad9361_auxdac_set, that is inspired from page 5 of UG 672.
Why there is not option to select the reference voltage and only vref 0 and 3 used?
The if condition is not clear to me.
the equation is :
( )=0.97× +(0.000738+9×10−6×( ×1.6−2))× [9:0]× − 0.3572× +0.05
however I see that because of step factor that is set to 0 on Reg 0x01A(D4) and Reg 0x01B(D4) the other part of equation is zero.
May be this is the one reason that the output voltage is not precised. But why there is a difference as we are writing the same value on both of the Registers 0x01A to 0x01B auxdac1 and 2 word (9:0);
Please let me knoo if we make the step_factor 1 how this equation should look like in the ad9361.c?
Did you observe the same problem.
Thanks in advance.