Section 17 RAM
17.1
Overview
The H8/3337Y, H8/3336Y, H8/3397, and H8/3396 have 2 kbytes of on-chip static RAM. The
H8/3334Y and H8/3394 have 1 kbyte. The RAM is connected to the CPU by a 16-bit data bus.
Both byte and word access to the on-chip RAM are performed in two states, enabling rapid data
transfer and instruction execution.
The on-chip RAM is assigned to addresses H'F780 to H'FF7F in the address space of the
H8/3337Y, H8/3336Y, H8/3397, and H8/3396 and addresses H'FB80 to H'FF7F in the address
space of the H8/3334Y and H8/3394. The RAME bit in the system control register (SYSCR) can
enable or disable the on-chip RAM.
17.1.1
Block Diagram
Figure 17.1 is a block diagram of the on-chip RAM.
Internal data bus (upper 8 bits)
Internal data bus (lower 8 bits)
H'F780
H'F782
H'F781
H'F783
On-chip RAM
H'FF7E
H'FF7F
Even address
Odd address
Figure 17.1 Block Diagram of On-Chip RAM (H8/3337Y)
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RENESAS [ RENESAS TECHNOLOGY CORP ]
