LinkIt 2523 HDK v11 User's Guide
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Figure 13. LED positions for LED9201, LED9206 and LED9209
4.5.
Buttons
The LinkIt 2523 HDK has four buttons that could support keypad functionality. To improve the pin usage on the
development board, the buttons could be designed with double key feature, as shown in Table 9.
The JTAG debug feature is assigned to the same set of pins as the buttons on the HDK. The pins are SW6502,
SW6503, SW6504 and SW6505 and they will be disabled when JTAG feature is enabled using one of the resistors
R9001 and R9007. The pin locations are shown in Figure 14.
To enable button or keypad functions on the HDK:
•
Remove 10k
Ω
resistor from R9001.
•
Mount 10k
Ω
resistor to R9002.
•
Set GPIO 18, GPIO 20 and GPIO 22 to keypad function using the Easy PinMux Tool (EPT).
Table 9. Buttons and corresponding keypad functionality
System reset
Push
Reset
to reset the HDK.
Power on
Push
PWR key
to power on the HDK with a battery. There is no need to press this
button, if the system is powered on with a USB cable as it will automatically turn
on.
Volume up
SW6502 button is assigned to control the volume up function.
Volume down
SW6503 button is assigned to control the volume down function.
Enter
SW6504 button is assigned to simulate
ENTER
key similar to the keypad.
LED9201
LED9209
LED9206
