C 8 0 5 1 F 3 2 6 / 7
6
Rev. 0.3
4.4. Expansion I/O Connector (J1)
The 22-pin Expansion I/O connector J1 provides access to all signal pins of the C8051F326 device. Pins for +3 V,
and digital ground are also available. A through-hole prototyping area is also provided. Each connection point is
labeled indicating the signal available at the connection point. See Table 3 for a list of pin descriptions for J1.
4.5. USB Self-powered Configuration
The C8051F326 target board can be powered from three different sources. The sources are the ac/dc adapter
(P1), USB connection (J9), and the USB Debug adapter (J4).
Only one power source should be enabled at any
time.
See Section 4.8. for infomation on using the USB Debug Adapter as a power source for the board.
The C8051F326 target board can be configured as a self-powered USB device to take power from the USB cable
at J9 instead of the ac/dc adapter connected at P1. To configure the target boards as a self-powered USB device,
remove the shorting block from J2 and install on J11. (A shorting block should only be installed on J2 or J11,
never
both at the same time
.) Install shorting blocks in the following manner:
J2(ON) & J11(OFF)
Target Board is powered from the ac/dc Adapter (P1).
J2(OFF) & J11(ON)
Target Board is powered from the USB connection (J9)
Notes:
• When the C8051F326 target board is self-powered from the USB connection (J9), the EC2 Serial Adapter is
not powered from the target board. The EC2 Serial Adapter must be powered directly by connecting the ac/
dc adapter to the Serial Adapter’s dc power jack.
• The RS232 Serial Interface (J5) cannot be used when powering the target board from the USB connection (J9).
Table 3. J1 Pin Descriptions
Pin #
Description
Pin #
Description
1
P0.0
12
P2.3
2
P0.1
13
P2.4
3
P0.2
14
P2.5
4
P0.3
15
P3.0
5
P0.4
16
C2CK/RST
6
P0.5
17
VREGIN
7
P0.6
18
VIO
8
P0.7
19
VBUS
9
P2.0
20
VDD
10
P2.1
21
+3VD
11
P2.2
22
GND
