TWR-KW2xDxxx
Tower KW2xDxxx Hardware Reference Manual, Rev. 0.2
3-8
Freescale Semiconductor
— An external unregulated supply up to 5.5VDC can be supplied to V_EXT header J28 making
use of the onboard 3.3 V LDO regulator
Header J2 provides the means to supply either the MCU, the radio and LED circuits. Current
measurements can be made by inserting a current meter in place of a designated jumper. Connections
configurations are described in
Table 3-2
.
3.2.4
TWR-KW2xDxxx Peripheral Functions
The TWR-KW2xDxxx includes the TWRPI general purpose peripheral function to assist in implementing
targeted applications. The TWR-KW2xDxxx board also has alternate port functions routed to the elevator
interface where off board tower system peripherals can be used if desired.
3.2.4.1
Serial FLASH (SPI Interface)
Component U13 is an AT45DB161E-SSHD 16 Mbit (2 Mbyte) serial Flash memory with SPI interface.
The memory is useful for over-the-air programming (OTAP) and for storage of non-volatile system data
or parameters.
Figure 3-7
shows the memory circuit.
•
Memory power supply is V_MCU
•
Discrete pullup resistors for the SPI port are provided
•
The SPI can be shared with another peripheral with the TWRPI J10 connector — an additional IO
signal would be required as a chip enable (CS or SS) for the peripheral. The normal SPI_SS and
the second chip select should NOT be active at the same time.
•
The SPI Write Protect and Reset signals have discrete pullup resistors for control if required. The
resistors are DNP.
Table 3-2. Power Distribution Header J2
Supply
Designation
Header
Pins
Description
V_LED
1 - 2
Supply voltage to power indicator LED
• Normally jumpered
• Jumper used to enable LEDs on board
• Leave open for lowest power
• Usage: Measure LED current
V_MCU
3 - 4
Supply voltage to MKW2xDxxx
• Normally jumpered
• Supplies only the MKW2xDxxx MCU
• Usage: Measure or supply MCU current
V_RF
5 - 6
Supply voltage to MKW2xDxxx
• Normally jumpered
• Supplies only the MKW2xDxxx transceiver
• Usage: Measure or supply radio current
