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AD9854 SPI programming

Question asked by basil on Sep 19, 2010
Latest reply on Sep 24, 2010 by basil

We are using a PC with 3.3V I/O Parallelport for programming. Since the pins are giving 3.3V, We need not have to add extra interface. My connections are shown below

 

D0 ----> SCLK

D1 ----> SDIO

D2 ----> CS#

D3 ----> IORST

D4 ----> UPD_CLK

D5 ----> SDIO_Buffer_enable

 

Where SDIO_Buffer_enable is used to enable the tristate buffer connected to D5. For write operation I will enable the buffer and for reading, I am disabling the buffer. So that when I am giving the read command, clock and control signal will be generated, and I can probe SDIO pin whether Iam reading properly.

 

 

 

The problem is that when reading SDIO pin is always low. What may be the reason??

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