USB930HXADBD ADAPTER BOARD USER’S GUIDE
6
4.3
Test Points
The board contains test points for CLK12MHZ, XTAL2, and AVCC.
4.4
Jumpers
The board contains jumpers to allow the 8x930Hx device to be reconfigured. Three 3-pin jumpers
are used to select the core operating frequency and the USB data rate.
Figure 1
illustrates jumper
configurations:
JW1 allows the clock oscillator to be disconnected from the 8x930Hx so that a crystal can be
used. To install your own crystal, you must either cut JW1 or remove the existing clock oscillator.
NOTE
When selecting 1.5Mbps with a 3MHz core, a 6MHz crystal must be installed
on the board.
4.5
Evaluation Board Interface
The 8x930Hx Adapter Board interfaces to the 8x930 Family Evaluation. Board. Rev B through
two 40-pin female headers. The headers are surface mounted on the solder side of the board. The
interface is “duplicated” physically and electrically on the component side of the board to allow
probing access.
4.6
Serial Communications
The adapter board contains the new 8x930Hx USB chip. This device has a default start-up inter-
nal frequency of 3 MHz. You can change this frequency to 12 MHz by clearing the LC bit located
in the PCON register. You can switch back to 3 MHz by setting the LC bit. Readers are encour-
aged to consult the 8x930Ax, 8x930Hx Universal Serial Bus Microcontroller User’s Manual
(order number 272949) for more information on this subject.
Table 1. Jumper Configuration
PLL2 JW4
PLL1 JW3
PLL0 JW2
USB Data
Rate
Core
Frequency
XTAL1
2-3
2-3
1-2
1.5 Mbps
3 MHz
6 MHz
1-2
2-3
2-3
1.5 Mbps
6 MHz
12 MHz
1-2
1-2
2-3
12 Mbps
12 MHz
12 MHz
