Q
The problem is very simple. The seriel programming Signals are provided by the
FPGA, but the AD5235 doesnA?t store the value. I think I am not providing all
needed signals or timings. Is it possible to get an explanation how to connect
the chip, focus on CS, WP and PR?
A
If you are not using WR and PR, then you should tie them high.
The /PR pin is a digital input, applying a logic low, will refresh the contents
of the scatch pad memory (RDAC register) with the current contents of the EEMEM
memory.
At power-on, the default value of the scatch pad memory is the value previously
saved in the EEMEM, therefore, to answer your question, on power-on the value
of the scatch pad will be loaded with the previously loaded contents of EEMEM,
without applying a logic low to /PR, you don't need an RC circuit connected to
/PR to ensure that the scatch pad is refreshed, as this is automatic on
power-up.
To write to the part, you need only to connect CS, SDI and SCLK.