Hi there guys.
first of all, pls excuse my bad english, i'm non native
my problem :
i have an AD9858/PCBZ Evaluation Board Z Ref(F) here, which is the
simple DDS DAC type of the board. I can run it via the given software
and get exactly the results as i expect them on the spectrum analyzer.
But now i want to (and actually need to) run it via LABVIEW to implement
it into my experimental setup. (i want to use it as a freq. generator).
to aquire control of the board i want to use the same LPT1 parallel port the
the problem is that i have no idea how to adress it correctly.
i know how to adress the registers and single bits of the registers of the parallel port
in labview via "Out Port.VI" and "In Port.VI".
what i dont know is, which pin (and thus bit of which register) corresponds to
which function / pin on the board.
what i know is the adressing inside the board which is explained in the datasheet.
for example how to set the Freq tuning word for profile 1. i know the adress and the value
i have to give it.
But how is it actually done ? I think i have to pull the "Write Pin / Bit" first and then
send adress and then the data ? is that correct ?
but which pin of the parallel port corresponds to the write? or read ? or reset ?
has anyone experience in using these kind of boards with labview ?
or is there a simpler way then giving it ones and zeroes ??
thanks for your help, much appriciated !
ps.: if there is any api, dll or similar available, pls tell. i'd be more than happy to use
that instead of doing it the way i try now ..
Unfortunately, I only have the data sheet to refer to.
send adress and then the data ? is that correct ? Yes, if you're programming in parallel mode.
Once you bring the WRB signal back high it will latch in the data into the addressed register. However, the data is held in buffered register. You have to send an IO_UPDATE to transfer the data to the active register. Note, read back reads back the active register not the buffered register.
but which pin of the parallel port corresponds to the write? pin 19 or read ? pin 22 or reset ? pin 92
has anyone experience in using these kind of boards with labview ? I have not, you might double check and search the DDS forum though., not sure
or is there a simpler way then giving it ones and zeroes ?? You can program the AD9858 in SPI mode or Parallel mode. The mode is determined by pin 91 (SP select). The data sheet talks about SPI mode but unfortunately there's no timing diagrams that I see. Note, you could look at the AD9854 data sheet, this part has the same SPI and parallel interface as the AD9858
Here a brief description of how to program the DDS.
1) Power up the device and apply the REF CLK source.
2) Pulse the master reset pin (required) This will place all the internal register to their default state. See Register map for default settings page 22.
3) Address the desired register in SPI or parallel mode
4) Send an IO_UPDATE. You can wait to program all registers and send one IO_UPDATE or send one for each register programmed, you're choice
5) The programmed DDS output should be present at the DDS output.