Accelerometer sensor

[amitaiwe]

motion sensoring

Hi,
I have bought a MMA7455 3-Axis Accelerometer Module and I want to use it for a simple purpose
which is getting an indication that a movement of an object ( in which the Accelerometer is) has occurred upwards or downwards.
The Accelerometer needs to send the information to a PIC16f877. The thing is that the PIC is also
connected to another component which communicates only via SPI protocol.
can i communicate with both the components one after another? (twice SPI or SPI and I2C?)
what are the things that need to be done for enabling that?

Thanks, Amitai

 

[aashishsharma]

Re: motion sensoring

SPI provides you the capability to select slave in general according to slave select input on SPI supported devices. You might want to use different pins on your microcontroller to provide Slave select input to devices and program those pins
Aashish

 

[amitaiwe]

I'm trying to figure out the wiring of the Accelerometer.
It's a module with a single data line for SDI/SDO. how does
it interface with a PIC which has a separate SDI and SDO ?
Do I need to connect them together and add a Schottky Diode as suggested here :
http://forums.netduino.com/index.php?/topic/7270-spi-learning-with-the-mma7455/
?

Thanks, Amitai

 

[aashishsharma]

Quick look at your problem shows that you have to switch to I2C. For SPI you need different pins for MISO and MOSI.
You may try diode ,it may work. Module does say it support SPI and I2C so it must have some means to use single dataline for SPI.