MPC555
/
MPC556
QUEUED ANALOG-TO-DIGITAL CONVERTER MODULE-64
MOTOROLA
USER’S MANUAL
Rev. 15 October 2000
13-10
Figure 13-3 Example of External Multiplexing
When the external multiplexed mode is selected, the QADC64 automatically creates
the MA[2:0] output signals from the channel number in each CCW. The QADC64 also
converts the proper input channel (ANw, ANx, ANy, and ANz) by interpreting the CCW
channel number. As a result, up to 32 externally multiplexed channels appear to the
conversion queues as directly connected signals. Software simply puts the channel
number of an externally multiplexed channel into a CCW.
shows that MA[2:0] may also be analog or digital input pins. When exter-
nal multiplexing is selected, none of the MA[2:0] pins can be used for analog or digital
inputs. They become multiplexed address outputs.
13.8 Analog Input Channels
The number of available analog channels varies, depending on whether or not external
multiplexing is used. A maximum of 16 analog channels are supported by the internal
multiplexing circuitry of the converter.
shows the total number of analog in-
put channels supported with zero to four external multiplexers.
AN52/MA0/PQA0
*
AN53/MA1/PQA1
*
AN54/MA2/PQA2
*
AN55/PQA3
*
AN56/PQA4
*
AN57/PQA5
*
AN58/PQA6
*
AN59/PQA7
*
AN0/ANW/PQB0
AN1/ANX/PQB1
AN2/ANY/PQB2
AN3/ANZ/PQB3
AN48/PQB4
AN49/PQB5
AN50/PQB6
AN51/PQB7
DIGITAL RESULTS
AND CONTROL
ANALOG
CONVERTER
ANALOG
MULTIPLEXER
VSSE
QADC64
VDDA
VSSA
VRL
V RH
MUX
AN0
AN2
AN4
AN6
AN8
AN10
AN12
AN14
MUX
AN1
AN3
AN5
AN7
AN9
AN11
AN13
AN15
MUX
AN16
AN18
AN20
AN22
AN24
AN26
AN28
AN30
MUX
AN17
AN19
AN21
AN23
AN25
AN27
AN29
AN31
ANALOG POWER
ANALOG REFERENCES
EXTERNAL TRIGGERS
PO
RT B
PO
RT A
VDDH
ETRIG1
ETRIG2
F
re
e
sc
a
le
S
e
m
ic
o
n
d
u
c
to
r,
I
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
n
c
.
..