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Memory Controller
MOTOROLA
MPC801 USER’S MANUAL
15-67
15
15.4 PROGRAMMING THE MEMORY CONTROLLER
You can interface with the memory controller by using eight identical sets of two
registers—the option register and the base register. There are also two identical registers
(MAMR and MBMR) that control the user-programmable A and B machines. There are also
some general registers.
15.4.1 Memory Status Register
The memory status register (MSR) is used to report parity or write-protect errors that are
found when accessing the external bus.
PER0—Parity Error Bank 0
This bit indicates that a parity error is detected when reading from Bank 0. PER0 is cleared
by writing a one to this bit or performing a system reset. Writing a zero has no effect on
PER0.
PER1—Parity Error Bank 1
This bit indicates that a parity error is detected when reading from Bank 1. PER1 is cleared
by writing a one to this bit or performing a system reset. Writing a zero has no effect on
PER1.
PER2—Parity Error Bank 2
This bit indicates that a parity error is detected when reading from Bank 2. PER2 is cleared
by writing a one to this bit or performing a system reset. Writing a zero has no effect on
PER2.
PER3—Parity Error Bank 3
This bit indicates that a parity error is detected when reading from Bank 3. PER3 is cleared
by writing a one to this bit or performing a system reset. Writing a zero has no effect on
PER3.
PER4—Parity Error Bank 4
This bit indicates that a parity error is detected when reading from Bank 4. PER4 is cleared
by writing a one to this bit or performing a system reset. Writing a zero has no effect on
PER4.
PER5—Parity Error Bank 5
This bit indicates that a parity error is detected when reading from Bank 5. PER5 is cleared
by writing a one to this bit or performing a system reset. Writing a zero has no effect on
PER5.
MSR
BIT
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
FIELD
PER0
PER1
PER2
PER3
PER4
PER5
PER6
PER7
WPER
RESERVED