HD6413258F10V Datasheet, PDF (207/301 Pages) Renesas Technology Corp – Regarding the change of names mentioned in the document, such as Hitachi Electric and Hitachi XX, to Renesas Technology Corp.

11.1.1 Block Diagram
Figure 11-1 is a block diagram of the on-chip ROM.
Internal data bus (upper 8 bits)
Internal data bus (lower 8 bits)
H'0000
H'0002
H'0001
H'0003
On-chip ROM
H'EFFE
H'EFFF
Even addresses Odd addresses
Figure 11-1. Block Diagram of On-Chip ROM (H8/3257)
11.2 PROM Mode
Fig 11-1
11.2.1 PROM Mode Setup
In the PROM mode of the PROM version of the H8/3257 and H8/3256, the usual microcomputer
functions are halted to allow the on-chip PROM to be programmed. The programming method is
the same as for the HN27C101. In the PROM mode of the PROM version of the H8/325, H8/323,
and H8/322 the usual microcomputer functions are halted to allow the on-chip PROM to be
programmed. The programming method is the same as for the HN27C256.
To select the PROM mode, apply the signal inputs listed in table 11-2.
Table 11-2. Selection of PROM Mode
Pin
Mode pin MD1
Mode pin MD0
STBY pin
Pins P70 and P71
Input
Low
Low
Low
High
202