User's Manual Part 1

USB stick board description
Wireless Sensing Triple Axis Reference design, Rev. 0.9
32 Freescale Semiconductor
4.2.6 Button connection
One button is implemented on the USB stick board. It is connected to the IRQ microcontroller pin that has
internal pull-up and allows an easy software interrupt.
4.2.7 MON08 interface
For MCHC908JW32 in-circuit programming, a MON08 interface is required. Several pins must be
connected to specific voltage levels in order for the MCHC908JW32 to enter the Monitor mode. The
details are described in the MCHC908JW32 datasheet, Chapter 7 Monitor ROM (MON).
To minimize the number of MON08 connections, several pins are hardwired to specific voltage levels
directly on the USB stick board. Namely, PTA1 to V
dd
, PTA2 and PTC1 to GND.
Pins PTA0, RST
, IRQ and OSC1, together with the power supply lines, are routed to PCB pads MON08
connector (J3).
There is no standard physical connector to be soldered onto the J3 footprint. The J3 connector pads are
used during manufacturing for the initial in-circuit programming. Further re-programming of the USB stick
maybe done using an AN2295
Bootloader as described in chapter 5.5.
4.2.8 Optional serial interface
For the purpose of evaluating the USB functions of the MCHC908JW32 microcontroller, a few other pins
were routed to an additional PCB pads connector (J2). The two TIM timer pins are connected to J2
allowing emulation of SCI, IIC or such like serial interfaces in software. A simple example of a USB to
UART converter software is a part of the
AN3153 Application note - Using the Full-Speed USB Module
on the MCHC908JW32
.