How to interface ADC with PIC micro using SPI protocol?

[preethi_das]

I want to interface ADC with PIC microcontroller using SPI protocol.and i want to know how SPI works .wat is the protocol ???? i want a detailed explanation about the protocol can any body please help me.

 

[Maddin]

spi detail explanation

I want to interface ADC with PIC microcontroller using SPI protocol.and i want to know how SPI works .wat is the protocol ???? i want a detailed explanation about the protocol can any body please help me.

In general you have 4 lines when using an SPI device:

/CS -> active low chip select that selects a specific ADC if you have multiple in your system (some ADC will start conversion only if the detect a falling edge of the signal)
SDI -> serial data input from SPI master (the one that generates the CLK signal is the master), usually not available on SPI ADC
SDO -> serial data output: data is bitwise clocked out from your ADC to the SPI master device (MCU)
CLK -> clock generated by the SPI master; SDI and SDO are synchronized to this signal when /CS is L

Concerning the exact timing for your system:
Check your ADC timing requirements in the ADC datasheet! A MCU has usually very flexible interface that can be programmed in different modes.
Anyway, take a look at http://www.ramtron.com/products/appnotes/spibuscomp.pdf which gives you some more information about the different SPI modes, addressing etc.
Hope it helped,
Maddin

 

[jzo777n]

motorola spi protocal

You could find some more information at Motorola's site
see for ex. **broken link removed**

 

[ME]

Yes, search Motorolas site for info, application notes and examples.
In fact Motorola invented the SPI interface.