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MPC555
/
MPC556
MODULAR INPUT/OUTPUT SUBSYSTEM (MIOS1)
MOTOROLA
USER’S MANUAL
Rev. 15 October 2000
15-22
• In the DIS mode, MDASMBR can be accessed to prepare a value for a subse-
quent mode selection. In this mode, register B1 is accessed in order to prepare a
value for the OPWM mode. Unused register B2 is hidden and cannot be read, but
is written with the same value when register B1 is written.
• In the IPWM mode, MDASMBR contains the captured value corresponding to the
leading edge of the measured pulse. In this mode, register B2 is accessed; buffer
register B1 is hidden and cannot be accessed.
• In the IPM and IC modes, MDASMBR contains the captured value corresponding
to the most recently detected period edge (rising or falling edge). In this mode,
register B2 is accessed; buffer register B1 is hidden and cannot be accessed.
• In the OCB and OCAB modes, MDASMBR is loaded with the value corresponding
to the trailing edge of the pulse to be generated. Writing to MDASMBR in the OCB
and OCAB modes also enables the corresponding channel B comparator until the
next successful comparison. In this mode, register B2 is accessed; buffer register
B1 is hidden and cannot be accessed.
• In the OPWM mode, MDASMBR is loaded with the value corresponding to the
trailing edge of the PWM pulse to be generated. In this mode, register B1 is ac-
cessed; buffer register B2 is hidden and cannot be accessed.
for a complete list of all the base addresses for the MDASM registers.
15.11.1.3 MDASM Status/Control Register (Duplicated)
The MDASMSCRD and the MDASMSCR are the same registers accessed at two dif-
ferent addresses. Reading or writing to either of these two addresses has exactly the
same effect.
NOTE
The user should not write directly to the address of the MDASM-
SCRD. This register’s address may be reserved for future use and
should not be accessed by the software to assure future software
compatibility.
for a complete list of all the base addresses for the MDASM registers.
MDASMBR
— MDASM Data B Register
0x30 605A*
MSB
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
LSB
15
BR
RESET:
U
U
U
U
U
U
U
U
U
U
U
U
U
U
U
U
MDASMSCRD
— MDASM Status/Control Register (Duplicated)
0x30 605C*
MSB
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
LSB
15
PIN
WOR
FREN
0
ED-
POL
FORC
A
FORC
B
RESERVED
BSL
0
MOD
RESET:
—
0
0
0
0
0
0
0
0
0
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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