RL78/G15 CHAPTER 3 CPU ARCHITECTURE
R01UH0959EJ0110 Rev.1.10 Page 63 of 765
Mar 7, 2023
3.2.3 Internal data memory space
The RL78/G15 products incorporate the following RAMs.
Table 3-4. Internal RAM Capacity
Part Number Internal RAM
R5F120x8 (x = 0, 1, 4, 6) 1024 × 8 bits (FFB00H to FFEFFH)
R5F120x7 (x = 0, 1, 4, 6)
The internal RAM can be used as a data area and a program area where instructions are fetched (it is prohibited to use
the general-purpose register area for fetching instructions). Four general-purpose register banks consisting of eight 8-bit
registers per bank are assigned to the 32-byte area of FFEE0H to FFEFFH of the internal RAM area.
The internal RAM is used as stack memory.
Caution It is prohibited to use the general-purpose register (FFEE0H to FFEFFH) space for fetching
instructions or as a stack area.
3.2.4 Special function register (SFR) area
On-chip peripheral hardware special function registers (SFRs) are allocated in the area FFF00H to FFFFFH (see Table
3-5 in 3.3.4 Special function registers (SFRs)).
Caution Do not access addresses to which SFRs are not assigned.
3.2.5 Extended special function register (2nd SFR: 2nd Special Function
Register) area
On-chip peripheral hardware special function registers (2nd SFRs) are allocated in the area F0000H to F07FFH (see
Table 3-6 in 3.3.5 Extended special function registers (2nd SFRs: 2nd Special Function Registers).
SFRs other than those in the SFR area (FFF00H to FFFFFH) are allocated to this area. An instruction that accesses the
extended SFR area, however, is 1 byte longer than an instruction that accesses the SFR area.
Caution Do not access addresses to which extended SFRs are not assigned.
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