Section 6 ROM
6.1 Overview
The H8/3862 and H8/3822 have 16 kbytes of on-chip mask ROM, the H8/3863 and H8/3823 have
24 kbytes, the H8/3864 and H8/3824 have 32 kbytes, the H8/3865 and H8/3825 have 40 kbytes, the
H8/3866 and H8/3826 have 48 kbytes, and the H8/3867 and H8/3827 have 60 kbytes. The ROM is
connected to the CPU by a 16-bit data bus, allowing high-speed two-state access for both byte data
and word data. The H8/3867 and H8/3827 have a ZTAT™ version with 60-kbyte PROM.
6.1.1 Block Diagram
Figure 6-1 shows a block diagram of the on-chip ROM.
Figure 6-1 ROM Block Diagram (H8/3864 and H8/3824)
H'7FFE
H'7FFF
Internal data bus (upper 8 bits)
Internal data bus (lower 8 bits)
Even-numbered
address
Odd-numbered
address
H'7FFE
H'0002
H'0000
H'0000
H'0002
H'0001
H'0003
On-chip ROM
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