NEC PD78214 - Manual (Page 384)

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Chapter 13 Local Bus Interface Function
13
13.2.4 Example of Connecting Memories
Fig. 13-10 shows an example of connecting memories to the
µPD78214. In this example, a PROM, SRAM, and
mask-programmable ROM are connected to the
µPD78214. Addresses are assigned to these memories as follows:
• PROM (
µPD27C512D-15)
: 0000H-FCFFH (
µPD78213)
2000H-0FD7FH (
µPD78212)
4000H-FCFFH (
µPD78214)
FFD0H-FFDFH as an external SFR area
• RAM (
µPD43256AC-12)
: 10000H-17FFFH
• Mask-programmable ROM (
µPD23C4000A) : 80000H-FFFFFH
Since the
µPD23C4000A mask-programmable ROM requires a long access time, insert one wait state by means
of the programmable wait function (See Section 13.4).
The circuit enclosed in dotted lines (74HC375) is required only when an in-circuit emulator is used. When the
emulator is not used, remove the 74HC375, and connect Dn and Qn (n = 1 to 4), respectively. If the emulator is used
without this circuit, malfunctions may occur. (Usually, however, normal operation is possible because of the
delays introduced by the address decoder and other circuitry.) When this circuit is not used, the 150-ns version,
the
µPD43256AC-15, can be used as RAM in place of the µPD43256AC-12.