Interfacing a PIC 18F452 and an ADC AD7827 + SPI com - Electronic Circuits Projects Diagrams Free

french_student · 5th December 2003, 08:21 AM

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 · 5th December 2003, 02:32 PM

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 · 8th December 2003, 09:15 AM

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.

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5th December 2003, 08:21 AM	(permalink)
french_student	Interfacing a PIC 18F452 and an ADC AD7827 + SPI com 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. __________________ French student is working and still working !!!

5th December 2003, 02:32 PM	(permalink)
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

8th December 2003, 09:15 AM	(permalink)
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. __________________ French student is working and still working !!!