MPC555
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MPC556
QUEUED ANALOG-TO-DIGITAL CONVERTER MODULE-64
MOTOROLA
USER’S MANUAL
Rev. 15 October 2000
13-11
13.9 Analog Subsystem
The QADC64 analog subsystem includes a front-end analog multiplexer, a digital to
analog converter (DAC) array, a comparator, and a successive approximation register
(SAR).
The analog subsystem path runs from the input pins through the input multiplexing cir-
cuitry, into the DAC array, and through the analog comparator. The output of the com-
parator feeds into the SAR.
shows a block diagram of the QADC64 analog submodule.
Table 13-2 Analog Input Channels
Number of Analog Input Channels Available
Directly Con External Multiplexed = Total Channels
1
NOTES:
1. When external multiplexing is used, three input channels become multiplexed address out-
puts, and for each external multiplexer chip, one input channel becomes a multiplexed ana-
log input.
No External
MUX Chips
One External
MUX Chip
Two External
MUX Chips
Three External
MUX Chips
Four External
MUX Chips
16
12 + 8 = 20
11 + 16 = 27
10 + 24 = 34
9 + 32 = 41
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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