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Load/retrieve AD9910 Ram using Eval board

Question asked by Biff on Mar 15, 2011
Latest reply on Mar 16, 2011 by Biff

I can control the registers to set things like single tone.  I have all of the control line functioning, not floating.

This is my approach to load ram

1 write to CFR1 with bit 31 set CS active during write with IO update

2 write profile 0 00b50001000000000 CS active during write with IO update (5 locations)

3 write address 0x16 CS active during write

4 write 5 data words toggling CS between each word

5 end with IO reset so next entry is address

 

read

1 read to CFR1  with IO update

2 read profile 0 00b50000400000000 active during read with IO update

3 write address 0x16 CS active during write

4 read 5 data words toggling CS between each word

5 end with IO reset so next entry is address

 

On the scope I see the data going into AD9910

After the adderss for the read back is sent the first ram location seems to be the power up state of the register, followed by 4 words with 0(should be 1,2,3,4)

 

What can cause the ram not to be filled/read back?

Documentations states that ram enable should be 0, but in register descriptions of CFR1 bit 31 it states that it needs to be set for load/retreive of ram.

Which is correct?

What happens if one write more data words that set up in  profile registe?

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