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AD9834 reset assertion before writing to FREQ0, FREQ1, PHASE0, PHASE1

Question asked by samuel.fmlourenco on Jan 10, 2018
Latest reply on Jan 11, 2018 by samuel.fmlourenco



I saw that figure 32 on the AD9834 datasheet suggests that the RESET pin should be asserted (I'm using control reg 0x2700, which means that B28 = 1, PIN/SW = 1) before setting the FREQ0, FREQ1, PHASE0 and PHASE1 registers. This means:

- Write control word 0x2700 (in order to set PIN/SW to 1);

- RESET pin set to 1 (asserted);

- Write to FREQ0, FREQ1, PHASE0 and PHASE1 registers;

- Set SLEEP, FSEL and PSEL pins as desired;

- RESET pin set to 0 (de-asserted).


Is this initialization procedure accurate?


Also, do I have to assert the RESET pin every time I wish to write to one of the above registers, de-asserting it later? Or is this just applicable to the initialization routine? Writing to these registers seems to take immediate effect without toggling RESET.


Kind regards, Samuel Lourenço