Vdda Select Header (W2) - Motorola M68MPB334 User Manual

2.2.2

VDDA Select Header (W2)

Jumper header W2 selects the MPB VDDA power source: either MPB power
(VDDI) or an external source. The drawing below shows the factory
configuration: a cut-trace short between pins 1 and 2. This configuration connects
filtered VDDI to VDDA.
To use an external power source, remove the cut-trace short from W2 pins 1 and
2, then connect the external power source to W2 pin 2. Removal of the cut-trace
short isolates the MCU VDDA pin from the other MPB circuitry. Isolation lets
you connect a precision VDDA source for accurate 10-bit analog/digital (A/D)
generation. When connecting an external VDDA power supply to the MPB,
connect the power supply ground to insertion point E1. For more information on
A/D generation refer to the Analog-To-Digital Converter Reference Manual,
ADCRM/AD.
M68MPB334UM/D
If the cut-trace short has been cut, you must install a fabricated
jumper on W2 to return it to the factory configuration.
Jumper header W2 is not populated by the factory.
HARDWARE PREPARATION AND INSTALLATION
W2
1
2
NOTES
2-5