how to change the default pin configuration

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

Yes, there is an onboard ADC on the RCM4000, it has 8 input channels, a programmable gain amplifier, and 11 bit resolution (TI claims 12, but with sign bit, not really). It uses the ports you referrenced and the ADC does tri-state its Data Out line when not selected. Therefore, as long as you use a device that does the same (non-obtrusive when not selected) you can share the SPI port. Of course, this means your code has to manage the SPI port to make sure only one device is being used at a time, and this is not built into the RCM4000 libraries so it would be your responsibility. Just make sure you never call an ADC routine while you have any of your other SPI devices enabled.

Remember with a receiver, that can mean leaving the device enabled whenever you want to be able to receive a transmission from another device. Unless the device buffers incoming data, you will probably be tying the SPI port up at that time. Of course if your not needing the ADC, none of this should be an issue.

3

ya. thanks for your reply. i got your answer. from that how can i disable ADC for my RF transmission purpose?

4

The ADC is by default disabled unless you call an ADC function. As long as you do nothing to use it, the serial port is yours to play with.