MPC555
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MPC556
QUEUED ANALOG-TO-DIGITAL CONVERTER MODULE-64
MOTOROLA
USER’S MANUAL
Rev. 15 October 2000
13-49
13.12.12 Result Word Table
The result word table is a 64-word long, 10-bit wide RAM. The QADC64 writes a result
word after completing an analog conversion specified by the corresponding CCW. The
result word table can be read or written, but in normal operation, software reads the
result word table to obtain analog conversions from the QADC64. Unimplemented bits
are read as zeros, and write operations have no effect.
While there is only one result word table, the data can be accessed in three different
alignment formats:
• Right-justified, with zeros in the higher order unused bits.
• Left-justified, with the most significant bit inverted to form a sign bit, and zeros in
the unused lower order bits.
• Left-justified, with zeros in the unused lower order bits.
The left-justified, signed format corresponds to a half-scale, offset binary, two’s com-
plement data format. The data is routed onto the IMB according to the selected format.
The address used to access the table determines the data alignment format. All write
operations to the result word table are right-justified.
The conversion result is unsigned, right-justified data. Unused bits return zero when
read.
The conversion result is signed, left-justified data. Unused bits return zero when read.
RJURR —
Right-Justified, Unsigned Result Register
0x30 4A80 – 0x30 4AFE
0x30 4E80 – 0x30 4EFE
MSB
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
LSB
15
RESERVED
RESULT
RESET:
0
0
0
0
0
0
LJSRR —
Left-Justified, Signed Result Register
0x30 4B00 – 0x30 4B7E
0x30 4F00 – 0x30 4F7E
MSB
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
LSB
15
S
1
NOTES:
1. S = Sign bit.
RESULT
RESERVED
RESET:
0
0
0
0
0
0
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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