MSP430FR2633: pin assignments(8x8 Touchpad)

Hi DDdoor,

Yes, Eason is correct.  The Captivate design center GUI will choose the optimal connections between the MCU and the sensor.  If you use the GUI's recommended connections, then you must create your PCB layout and routing to match.  Most of the time (especially with touchpads) this is not possible, due to the size of the PCB and other issues making it difficult to route the PCB traces between the MCU and the touchpad. So you have to decide these connections manually.

There is a procedure for picking the pins in the correct order and is described in a section in the Captivate technology guide.  Although the examples are showing multi element sliders, the same procedure applies to touchpads.

I'll use and 8x8 touchpad as an example and summarize here:

The RX pin assignments are important must be made in a specific order starting from block CAP0 through block CAP3.

1. Always start with CAP0 and choose any pin to be RX0. Next, on CAP1, choose any pin to be RX1.  On CAP2, choose any pin to be RX2 and on CAP3 choose any pin to be RX3.

2. For RX4 through RX7, repeat step (1) and assign RX4, RX5, RX6 and RX7 to any available pins, starting over with CAP0 through CAP3.

3. The TX pin assignments don't have any special order.  You can choose any pin on any block for the TX0 through TX7 assignments.  Whatever makes it easiest to route your PCB traces.

Here is an illustration.

Do you notice that the diagram you provided follows the same ordering method?

Here is an example showing the connections on an 8X8 that uses the 48pin connector on the Captivate EVM

Here is the entire layout.