Interfacing a PIC 18F452 and an ADC AD7827 + SPI com

[french_student]

Hello,

I need to interface a PIC 18F452 with an external ADC, the AD7827 wich is an 8-bit ADC with serial interface. I want to establish the communication between the PIC and the ADC with the PIC's SPI module. But I have a problem. In fact i'd need to have the clock signal output working more than 8 times (not only when the PIC reads the value on his SDI pin), because my ADC need it to realise the conversion and serialization. I read the PIC datasheet, but i stille don't know if i could that: how can i send the SCK signal to the ADC more than 8 times so how can i send this signal even if i don't read the value on the SDI pin?

I hope my question is clear enough.
Thanks for your answers.

 

[ivancho]

Why don't yo use the ADC in the PIC, it will convert faster and you will have less hardware to take care of. :wink:

Ivancho

 

[french_student]

Thanks for your answer

But the reason why i don't use the ADC in the pic is that it's too slow! The conversion time is really too slow for the applications i need to do.

So if you have any other idea, it will be great!!

Thanks.