Freedom Board for Kinetis K22F Hardware (FRDM-K22F) User’s Guide, FRDMK22FUG, Rev. 0, 07/2014

Freescale Semiconductor, Inc.

13

Serial Port

10 Serial Port

The primary serial port interface signals are PTE1 UART1_RX and PTE0 UART1_TX. These signals are

connected to the OpenSDAv2 circuit.

11 Reset

The Reset signal on the K20 is connected externally to a push button, SW1, and also to the OpenSDAv2

circuit. The reset button can be used to force an external reset event on the target MCU. The reset button

can also be used to force the OpenSDAv2 circuit into boot loader mode. For more details, see Section 3.2,

“Serial and Debug Adapter version 2 (OpenSDAv2)”.

Figure 13. Reset circuit

12 Push Button Switches

Two push buttons, SW2 and SW3, are available on the FRDM-K22F board. SW2 is connected to PTC1

and SW3 is connected to PTB17. Besides the general purpose input/output functions, SW2 can be also be

used as a low-leakage wakeup (LLWU) source.

Table 6. LED signal connection

RGB LED

K22F Connection

RED

PTA1/UART0_RX/FTM0_CH6/JTAG_TDI/EZP_DI

GREEN

PTA2/UART0_TX/ FTM0_CH7/JTAG_TDO/TRACE_SWO/EZP_DO

BLUE

PTD5/SPI0_PCS2/UART0_CTS_b/FTM0_CH5/FB_AD1/ EWM_OUT_b/SPI1_SCK