pls help on SPI interfacing

Rabbit
1

hi friends
i am using RCM4000. I have a doubt which i cant clear by myself. so i am here. i want to change the default pin confic by hardware.

let me explain with an example

"PB7 acts as the CS line on the ADC
PB0 is the serial B clock line(SCLK)

PC4 is the data output(MOSI)
PC5 is the data input(MISO)"

I found this from the sample program of SPI folder and file name is SPI_TEST.C. they declared those pins for there purpose. when i run this program its showing a default value 0XFF. if then is there really a ADC inbuild? and if this ADC using those pins for SPI can i use any other SPI interface like RF transmitting with the same pins with out disabling the exist ADC and can i get the perfect output?

I have connected one RF transceiver using SPI to RCM4000. first i want to check whether my RF module Receiving the data or not at the SPI MISO pin using LED!!! as well as at the transmitting pin MOSI.
how can do this with an LED at my transmitting board itself.

my another doubt is using RF Transceiver can i transmit the data and receive the same data using some time delay by the same RF Transceiver???i.e there is separate Receiver, at my RCM4000 board itelf… pls clear my doubt…

2

You can use whichever pins you choose to interface over SPI.
If you choose to use the same pins as the built in ADC, then make sure you use a separate line for CS, so long as you do not have more than one device selected at a time, you can safely mutliplex the data and clock lines.

If you are getting 0xFF back from the ‘built in’ ADC, then maybe there isn’t one built in - check the model of board you are using against the specifications and that will tell you.

You could add LEDs to the data and clock lines, but what would that tell you? LEDs are not a great debug tool as they change the electrical characterstics of the circuit. A better solution would be a scope such as the PicoScope 2105 or a similar.

Finally, if I understand you correctly, you are asking if you can receive your own data back on the same RF Transceiver - well I think that totally depends on the make/model of the transceiver and whethere it disables the receiver while it is transmitting. If it transmits and receives on the same channel then you will probably get an echo back anyway.

3

Thanks for your reply.
really it helps. yes, my RCM4010 has no inbuilt ADC at all. Really thanks for your reply.