15
The signal purpose of the IP is described in
Table 3-6.
The IP requires a 50 MHz signal as a
reference clock to the iCLK pin and system reset signal to iRSTN. iTRIG, I2C_SCLK, and
IC2_SDAT pins should be connected of the TOUCH_INT_n, TOUCH_I2C_SCL, and
TOUCH_I2C_SDA signals in the 2x20 GPIO header respectively. When oREADY rises, it means
there is touch activity, and associated information is given in the oREG_X1, oREG_Y1, oREG_X2,
oREG_Y2, oREG_TOUCH_COUNT, and oREG_GESTURE pins.
For the control application, when touch activity occurs, it should check whether the value of
oREG_GESTURE matched a pre-defined gesture ID defined in
Table 3-7.
If it is not a gesture, it
means a single-touch has occurred and the relative X/Y coordinates can be derived from oREG_X1
and oREG_Y1.
Table 3-6 Interface Definitions of Terasic Multi-touch IP
Pin Name
Direction
Description
iCLK
Input
Connect to 50MHz Clock
iRSTN
Input
Connect to system reset signal
iTRIG
Input
Connect to Interrupt Pin of Touch IC
oREADY
Output
Rising Trigger when following six output data
is valid
oREG_X1
Output
10-bits X coordinate of first touch point
oREG_Y1
Output
9-bits Y coordinate of first touch point
oREG_X2
Output
10-bits X coordinate of second touch point
oREG_Y2
Output
9-bits Y coordinate of second touch point
oREG_TOUCH_COUNT
Output
2-bits touch count. Valid value is 0, 1, or 2.
oREG_GESTURE
Output
8-bits gesture ID (See
Table 3-7)
I2C_SCLK
Output
Connect to I2C Clock Pin of Touch IC
I2C_SDAT
Inout
Connect to I2C Data Pin of Touch IC
The supported gestures and IDs are shown in
Table 3-7.
