
CPU16
REFERENCE MANUAL
DEVELOPMENT SUPPORT
MOTOROLA
10-31
RDMEM
Description:
Read Data Space Memory
RDMEM
A byte, word, or long word is read from an address in data space
and transmitted via the serial link.
Two extension words specify 20-bit memory address and operand
size. Bits [3:0] of the first word are the bank address. Bits [15:14] are
encoded to specify operand size. Bits [13:4] are reserved for future
use. The second word is the operand address.
Operand:
Result:
Eight, 16, and 32-bit data. Eight and 16-bit data are transmitted as
16-bit data words, MSB first. For 8-bit data, the upper byte of each
word contains $FF. 32-bit data is transmitted as two 16-bit data
words in MSW, LSW order beginning with the MSB of each word.
Command Format:
15
14
13
12
11
10
9
8
Command Sequence Diagram:
Table 10-6 Operand Size Encoding
Bits
[15:14]
00
01
1X
Operand
Size
Byte
Word
Long Word
7
6
5
4
3
2
1
0
0
0
0
1
0
1
1
1
1
0
0
0
0
1
0
0
EXT WD 1
NOT READY
NOT USED
ILLEGAL
EXT WD 2
NOT READY
RESULT
NOT USED
NOT READY
RESULT
NOT USED
NOT READY
NOT USED
RESULT
NOT USED
NOT READY
WORD
LONG
WORD
RDMEM
*
NEXT CMD
NOT READY
BYTE
READ
MEMORY
LOCATION
READ
MSW
LOCATION
READ
LSW
LOCATION
*RESULTS OF PREVIOUS COMMAND
OR COMMAND COMPLETE STATUS
NEXT CMD
NOT USED
F
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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