HARDWARE PREPARATION AND INSTALLATION
M68MPB16R3UM/D
2-3
Table 2-1. Jumper Header Types
Jumper Header
Type
Symbol
Description
two-pin with cut-trace
short
Two-pin jumper header with cut-trace short, designated WX,
where X = the jumper header number. If you cut the short, use a
fabricated jumper to return the jumper header to its factory default
state.
three-pin
Three-pin jumper header, designated WX, where X = the jumper
header number. Use a fabricated jumper to create a connection
between two of the three pins of the jumper header.
Table 2-2. MPB Jumper Header Descriptions
Jumper
Header
Type
Description
W1
1 2 3
Jumper between pins 1 and 2 (factory default); selects the MPB on-board
crystal clock source.
Jumper between pins 2 and 3; selects an external clock source as the MCU
EXTAL input signal.
W2
1
2
Jumper installed or cut-trace short intact (factory default); selects the on-board
VDDA power source.
No jumper or cut-trace short; lets you connect an external power source to W2
pin 2 and the external-power-source ground to E1.
NOTE
Jumper header W2 is not populated by the factory.
W3
1 2 3
Jumper installed on pins 1 and 2 (factory default); selects the MPB on-board
VRH power source.
Jumper installed on pins 2 and 3; selects an external VRH power source.
W4
1 2 3
Jumper installed on pins 1 and 2 (factory default); selects the MPB on-board
VRL power source.
Jumper installed on pins 2 and 3; selects an external VRL power source.