NEC 78014Y Series, User Manual

Page: 101 / 547

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CHAPTER 5 CPU ARCHITECTURE
101
5.1.2 Internal data memory space
The
µ
PD78014 and 78014Y Subseries incorporate the following RAMs.
(1) Internal high-speed RAM
The
µ
PD78014 and 78014Y Subseries incorporate the following capacity of internal high-speed RAM in each
product.
Table 5-3. Internal High-Speed RAM Capacities
Part Number Internal High-speed
RAM Capacity
µ
PD78011B, 78011BY 512
×
8 bits
µ
PD78012B, 78012BY
µ
PD78013, 78013Y 1024
×
8 bits
µ
PD78014, 78014Y
µ
PD78P014, 78P014Y
4 banks of general registers, each bank consisting of eight 8-bit registers are allocated in the 32-byte area FEE0H
to FEFFH.
The internal high-speed RAM can also be used as a stack memory area.
(2) Buffer RAM
Buffer RAM is allocated to the 32-byte area from FAC0H to FADFH. Buffer RAM is used for storing transmit/
receive data of serial interface channel 1 (3-wire serial I/O mode with automatic transmit/receive function). When
not used in the 3-wire serial I/O mode with automatic transmit/receive function, buffer RAM can also be used
as normal RAM.
5.1.3 Special function register (SFR) area
An on-chip peripheral hardware special-function register (SFR) is allocated in the area FF00H to FFFFH (refer
to Table 5-5. Special Function Register List of 5.2.3 Special function register (SFR)).
Caution Do not access addresses where the SFR is not assigned.
5.1.4 External memory space
External memory space that can be accessed by setting a memory expansion mode register (MM). Program and
table data can be stored, and peripheral devices can be allocated.