HD6417021 Hitachi Semiconductor, HD6417021 Datasheet - Page 139

• Manufacturer Part Number: HD6417021
• Description: SuperH RISC engine
• Manufacturer: Hitachi Semiconductor

Areas 2–4 are always used as external memory space. The bus width is 8 bits when the A27 bit is
0 and 16 bits when it is 1. A23 and A22 bits are not output and the shadow is in 4-Mbyte units.
When areas 2–4 are accessed, the CS2, CS3, and CS4 signals are valid. Area 2 has a long wait
function, so between 1 and 4 states can be selected for the number of long waits inserted into the
bus cycle using the bits A02LW1 and A02LW0 of WCR3.
H'A000000
H'A3FFFFF
H'A400000
H'A7FFFFF
H'A800000
H'ABFFFFF
H'AC00000
H'AFFFFFF
16-bit space
H'2000000
H'23FFFFF
H'2400000
H'27FFFFF
H'2800000
H'2BFFFFF
H'2C00000
H'2FFFFFF
Logical address space
Figure 8.7 Memory Map of Area 2
Shadow
Shadow
Shadow
Shadow
8-bit space
• Valid addresses A21–A0
• CS2 valid
• Long wait function
(A23 and A22 not output)
memory space
Actual space
(4 Mbytes)
External
HITACHI 123