TMP91C824
91C824-81
2008-02-20
(1)
Memory start address registers
Figure 3.6.1 shows the memory start address registers. The memory start address
registers MSAR0 to MSAR3 set the start addresses for the CS0 to CS3 areas. Set the
upper 8 bits (A23 to A16) of the start address in <S23:16>. The lower 16 bits of the
start address (A15 to A0) are permanently set to 0. Accordingly, the start address can
only be set in 64-Kbyte increments, starting from 000000H. Figure 3.6.2 shows the
relationship between the start address and the start address register value.
Memory Start Address Registers (for areas CS0 to CS3)
7 6 5 4 3 2 1 0
Bit
symbol
S23 S22 S21 S20 S19 S18 S17 S16
Read/Write
R/W
After
reset
1 1 1 1 1 1 1 1
Function
Determines A23 to A16 of start address.
Figure 3.6.1 Memory Start Address Register
64 Kbytes
Figure 3.6.2 Relationship between Start Address and Start Address Register Value
MSAR0
(00C8H)
MSAR1
(00CAH)
MSAR2
(00CCH)
MSAR3
(00CEH)
Sets start addresses for areas CS0 to CS3.
Address
000000H
FFFFFFH
000000H ...................... 00H
010000H ...................... 01H
020000H ...................... 02H
030000H ...................... 03H
040000H ...................... 04H
050000H ...................... 05H
060000H ...................... 06H
FF0000H ...................... FFH
Start address
Value in start address register (MSAR0 to MSAR3)
to to