Filter
Top Products
513
Chapter 31 External Bus
2.External Bus Interface Registers
Figure 2-1 Configuration of the Area Select Registers (ASR0-7)
■ Functions of Bits in the Area Select Registers (ASR0-7)
The start address can be set in the high-order 16 bits (bits A31-A16). Each chip select area starts with the
address set in this register and covers the range set by the four bits ASZ3-0 of the ASR0-7 registers.
The boundary of each chip select area obeys the setting of the four bits ASZ3-0 of the ACR0-7 registers. For
example, if an area of 1 MB is set by the four bits ASZ3-0, the low-order four bits of the ASR0-7 registers are
ignored and only bits A31-20 are valid.
The ASR0 register is initialized to 0000
H
by INIT and RST. ASR1-7 are not initialized by INIT and RST, and are
therefore undefined. After starting chip operation, be sure to set the corresponding ASR register before enabling
each chip select area with the CSER register.
2.2 Area Configuration Registers 0-7 (ACR0-7)
This section explains the configuration and functions of area configuration registers 0-7 (ACR0-
7).
■ Configuration of Area Configuration Registers 0-7 (ACR0-7)
The area configuration registers 0-7 (ACR0-7: FArea Configuration Register 0-7) set the function of each chip
Initial value
ASR0 15 14 13 12
210
INIT RST Access
00000640
H
A31 A30 A29
A18 A17 A16 0000
H
0000
H
W/R
ASR1 15 14 13 12
210
00000644
H
A31 A30 A29 A18 A17 A16 xxxx
H
xxxx
H
W/R
ASR2 15 14 13 12 210
00000648
H
A31 A30 A29
A18 A17 A16 xxxx
H
xxxx
H
W/R
ASR3 15 14 13 12 210
0000064C
H
A31 A30 A29 A18 A17 A16 xxxx
H
xxxx
H
W/R
ASR4 15 14 13 12 210
00000650
H
A31 A30 A29 A18 A17 A16 xxxx
H
xxxx
H
W/R
ASR5 15 14 13 12 210
00000654
H
A31 A30 A29 A18 A17 A16 xxxx
H
xxxx
H
W/R
ASR6 15 14 13 12 210
00000658
H
A31 A30 A29 A18 A17 A16 xxxx
H
xxxx
H
W/R
ASR7 15 14 13 12 210
0000065C
H
A31 A30 A29 A18 A17 A16 xxxx
H
xxxx
H
W/R