Motorola MPC533 Reference Manual page 471

corresponds to a location in the result word table. When a conversion is completed for a
CCW entry, the 10-bit result is written in the corresponding result word entry. The
QADC64E provides 64 CCW table entries.
The beginning of queue 1 is the first location in the CCW table. The first location of queue
2 is specified by the beginning of queue 2 pointer (BQ2) in QACR2. To dedicate the entire
CCW table to queue 1, queue 2 is programmed to be in the disabled mode, and BQ2 is
programmed to 64 or greater. To dedicate the entire CCW table to queue 2, queue 1 is
programmed to be in the disabled mode, and BQ2 is specified as the first location in the
CCW table.Figure 13-13 illustrates the operation of the queue structure.
Conversion Command
Word (CCW) Table
0x200 (ccw0)
Begin Queue 1
End of Queue 1
BQ2
Begin Queue 2
End of Queue 2
0x27E (ccw63)
P BYP IST
P = Pause After Conversion
BYP = Bypass Buffer Amplifier
IST = Input Sample Time
CHAN = Channel Number
and End_of_Queue Code
10-bit Conversion
Command Word
(CCW) Format
Note 1: These offsets must be added to the module base address: A = 0x30 4800.
Figure 13-13. QADC64E Conversion Queue Operation
To prepare the QADC64E for a scan sequence, the software writes to the CCW table to
specify the desired channel conversions. The software also establishes the criteria for
initiating the queue execution by programming the queue operating mode. The queue
operating mode determines what type of trigger event causes queue execution to begin. A
MOTOROLA Chapter 13. Queued Analog-to-Digital Converter Legacy Mode Operation
PRELIMINARY—SUBJECT TO CHANGE WITHOUT NOTICE
A/D Converter
Channel Select,
Sample, Hold,
and
Analog to Digital
Conversion
CHAN
Programming the QADC64E Registers
Result Word Table
0
5 6
0 0 0 0 0 0
Result
Right Justified, Unsigned Result Format
0
9 10
0 0
S Result
Left Justified, Signed Result Format
0
9 10
Result 0 0
Left Justified, Unsigned Result Format
10-bit Result is
Software Readable
in 3 Different 16-bit Formats
Result 0
Result 63
Address Offsets
15
1
0x280-0x2FF
15
1
0 0 0 0
0x300-0x37F
S = Sign bit
15
1
0x380-0x3FF
0 0 0 0
13-27