MSP430G2553: 2Channel UP/DOWN counting by using timers with capture with MSP430G2553

Hello,

I would like to do the following:

ChA_UP_CLK         ---> |                                 |

ChA_DOWN_CLK  ---> |   MSP430G2553  | -> SDA

ChB_UP_CLK         ---> |                                | -> SCL

ChB_DOWN_CLK  ---> |                                |

So basically,  I want to count 2 channels of up/down clocks, by means of a timer/counter, and configure one pin as up_clk, and one pin as down_clk to the same timer/counter. And do this for 2 channels,

while communicating with a i2c master as slave, tru SDA and SCL.

The reason I would like to do this is to make a i2c quadrature encoder interface. Using a set of logic circuits, I convert the quadrature encoder output to a up_clk and down_clk. counting them is easier than an interrupt based system decoding the encoder output directly.

Any ideas/help or recommendations greatly appreciated.

-CA