AD 9520 EEprom

Dear all,

I'm having problems in programming the EEPROM of the AD9520.

I use the SPI to program the PLL.

When I try to configure directly the PLL via SPI, it works and the wanted clock is at the output;

I can see the lock signal at '1' and everything goes fine.

When I try to program the EEPROM, problems start.

I am doing as follows:

1) I program the PLL as I want ( and I see the lock at '1'); in particular, I set the status pin in such a way to see the EEPROM status

2) I set 0xb02[0] at '1'

3) I set 0xb03[0] at '1'

4) I set an update with 0x232[0] at '1'

I do not see the status pin at '1' (as it should be during the EEPROM programming) and it looks like the eeprom is not programmed at all; if I try to give a self-clearing soft reset (0x000[5]), with the EEPROM pin high I do not see the new configuration loaded.

The strange part is that if I try to set 0xb02[0] at '1', set 0xb02[0] at '1' and then 0x232[0] at '1', as soon as I try to read again 0xb02[0] it is at '0' ( it looks like the EEPROM write is not enabled). I also tried to set 0xb02[0] at '1' and update but when I read it back, it is at '0'.

Any ideas?