PIC16F88 I2C Accelerometer Help

[Tabsoft]

Are you using PICBasic or PICBasic Pro?
It makes a difference.

[Tabsoft]

Perhaps this will help.

Looking at the MMA7455 datasheet the I2C Device address is "$1D"
Also to communicate using I2C with the MMA7455 you need to make sure that MMA7455's CS pin is pulled high.

You should not have to issue a write then a read.
I2CRead does this for you.

With PBP Pro, to issue a PBP I2CRead command here is the syntax:
I2CREAD DataPin, ClockPin, Control,{Address,}[Var{,Var...}]{,Label}
"Control" is the MMA7455 I2C Slave Address "$1D"
"Address" is the MMA7455 Register address you want to read, in this case "$07" for "YOUT8".
"Var" will be a single Byte variable because you are only reading a single byte from the MMA7455.

So something like this.

yout var byte 'Holds the value read from the MMA7455 YOUT8 register
addr var byte 'Holds register address

addr = $07 'Assign $07 to access the MMA7455's YOUT8 register

I2CREAD DPIN1, CPIN1, $1D, addr, [yout]

[Tabsoft]

After reading a couple other forums, the MMA7455L slave address of $1D is a 7bit address so you need to left shift $1D 1 bit. This makes the address $3A. ($1D << 1 = $3A).
In an 8bit I2C address the upper 7bits is the device address <7:1> and the LSB <0> is the R/W bit.


So in binary:
$1D = %0001 1101 (7bit address)
$3A = %0011 1010 (7bit address + R/W bit)

The I2CREAD statement should look like this.
addr var byte
yout var byte

addr $07

I2CREAD DPIN1, CPIN1, $3A, addr, [yout]

Hopefully this will work for you.