Toshiba TMP91C815F Data Book page 85

(3) Setting Memory Start Addresses and Address Areas
Figure 3.6.4 show an example of specifying a 64K-byte address area starting from 010000H
using the CS0 areas.
Set "01H" in memory start address register MSAR0<S23 to S16>(corresponding to the upper 8 bits
of the start address). Next, calculate the difference between the start address and the anticipated end
address (01FFFFH). Bits 20 to 8 of the result correspond to the mask value to be set for the CS0 area.
Setting this value in memory address mask register MAMR0<V20 to V8>sets the area size This
example sets "07H" in MAMR0 to specify a 64K-byte area.
0 0 0 0 0 0
0
S23 S22 S21 S20 S19 S18 S17 S16
MSAR0
0 0 0 0 0 0
0
V20 V19 V18 V17 V16 V15
MSMR0
0 0 0 0 0 0
0
After a reset, MSAR0 to MSAR3 and MAMR0 to MAMR3 are set to "FFH".B0CS<B0E>,
B1CS<B1E> and B3CS<B3E> are reset to "0".this disabling the CS0, CS1 and CS3 areas.
However, as B2CS<B2M> to "0" and B2CS<B2E> to "1", CS2 is enabled from
000FE0H-000FFFH to 003000H-FFFFFFH in TMP91C815. Also, the bus width and number of
waits specified in BEXCS are used for accessing addresses outside the specified CS0 to CS3 area.
(See 3.6.2, Chip Select/Wait Control Registers.)
0 1 1 1 1 1 1 1
1 F
0 1
1 H
V14 ∼ V9
0 0 1 1 1 1 1 1
7
Setting of 07H specifies a 64-Kbyte area.
Figure 3.6.4 Example showing how to set the CS0 area
91C815-
1 1 1 1 1 1 1 1
F F
V8
1 1 1 1 1 1 1 1
H
82
TMP91C815
Memory
1 1
end
H
F
address
CSO area
size
(64 Kbytes)
Memory
start
address
Memory address
1 1 H
mask register
setting