Ram - Hitachi H8/300L Series Manual

12. RAM

The H8/300L Series product lineup includes microcomputers with on-chip RAM capacities
from 512 bytes to 2 kbytes. The H8/300L Series RAM is connected to the CPU over a 16-bit
data bus, and can be accessed in only 2 states in both byte and word access modes. Due to the
speed of this RAM, the H8/300L CPU can execute data handling instructions in only 0.4 µs.
Block Diagram
Note: This figure shows the H8/3724 512-byte RAM.
A short absolute addressing mode is provided by the H8/300L Series CPU MOV instruction
for rapid access to locations from H'FF00 to H'FFFF. Furthermore, programs can be coded
compactly due to the short instruction length. Since RAM locations H'FF00 to H'FF7F can be
accessed by this short absolute addressing mode, programs can use this mode to implement
high speed data handling.
Internal data bus (upper 8 bits)
Internal data bus (lower 8 bits)
H'FD80 H'FD80
H'FD82 H'FD82
H'FF7E H'FF7E
Even addresses
H'FD81
H'FD83
H'FF7F
Odd addresses
117
Peripheral Functions