HITACHI 121
H'8000000
H'83FFFFF
H'8400000
H'87FFFFF
H'8800000
H'8BFFFFF
H'8C00000
H'8FFFFFF
H'0000000
H'0400000
H'0800000
H'0C00000
H'03FFFFF
H'07FFFFF
H'0BFFFFF
Shadow
Shadow
Shadow
Shadow
8 or 16
bit space
MD2–MD0 = 000 or 001
MD2–MD0 = 010
H'8000000
H'8003FFF(SH7020)
H'8007FFF(SH7021)
H'8004000(SH7020)
H'8008000(SH7021)
H'8FFC000
(SH7020)
H'8FF8000
(SH7021)
On-chip ROM
SH7020:
16 kbyte
SH7021:
32 kbyte
Valid
addresses
A15–A0
(A23–A16
ignored)
CS0 not
valid
Shadow
Shadow
Shadow
Shadow
Shadow
Shadow
Actual space
Logical address space
Logical address space
H'0FFFFFF
H'0FFFFFF
8 or 16
bit space
32-bit space
H'0FFC000
(SH7020)
H'0FF8000
(SH7021)
32-bit space
Actual space
MD2–MD0 =
000: 8-bit
access,
001: 16-bit
access
Valid
addresses
A21–A0
(A23 and
A22 not
output)
CS0 valid
Long wait
function
H'0000000
H'0003FFF
(SH7020)
H'0007FFF
(SH7021)
H'004000
(SH7020)
H'0008000
(SH7021)
External
memory
space
(4 Mbytes)
Note:
The bus width of area 0 is determined by the MD2–MD0 pins regardless of the A27 bit
setting.
Figure 85 Memory Map of Area 0
Area 1:
Area 1 is the area where addresses A26–A24 are 001 and its address range is H'1000000–
H'1FFFFFF and H'9000000–H'9FFFFFF. Figure 8.6 is a memory map of area 1.
Area 1 can be set for use as DRAM space or external memory space with the DRAM enable bit
(DRAME) of the bus control register (BCR). When the DRAME bit is 0, it is external memory
space; when DRAME is 1, it is DRAM space.
In external memory space, the bus width is 8 bits when the A27 bit is 0 and 16 bits when it is 1.
Bits A23 and A22 are not output and the shadow is in 4-Mbyte units. When external memory is
accessed, the
CS1
signal is valid.
DRAM space is a type of external memory space, but it is configured especially to be connected to
DRAM so it outputs strobe signals required for this purpose. Its bus width is 8 bits when it is 0 and
16 bits when it is 1. When the multiplex enable bit (MXE) of the DRAM control register (DCR) is