mca8652FC device address for I2C/TWI

[superman]

Hi,

I am using mca8652fc and used device address as #define ACCELEROMETER_ADDR 0x1D but it is not reading WHO_AM_I register properly. I used #define ACCELEROMETER_ADDR (0x3AU >> 1) instead this is also not working. Do you have any idea on this? data sheet says 3B is for read and 3A for write. By following example code "twi sensor" given in SDK10.

Thanks

[MartinBL]

Hi,

0x1D is probably the address you should use with the functions in the SDK. Here is an explanation of why you sometimes have to shift the address left or right and why the read/write address might appear to be different.

In SDK 12.2.0 there is a simple TWI example called 'twi_scanner' that you can use to check all addresses on the TWI bus and see which one responds. It is a good example to use just to check that you have connected everything correctly and what address to use. Here are similar examples for older SDKs.

[awneil]

See also: www.avrfreaks.net/.../1872781

"The discrepancy between talking of I2C addresses as 7 or 8 bits is very common indeed"