D784927_15 Datasheet, PDF (22/99 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCONTROLLER

µPD784927, 784928, 784927Y, 784928Y
3. INTERNAL BLOCK FUNCTION
3.1 CPU Registers
3.1.1 General-purpose registers
The µPD784927 has eight banks of general-purpose registers. One bank consists of sixteen 8-bit general-purpose
registers. Two of these 8-bit registers can be used in pairs as a 16-bit register. Four of the 16-bit general-purpose
registers can be used to specify a 24-bit address in combination with an 8-bit address expansion register.
These eight banks of general-purpose registers can be selected by software or context switching function.
The general-purpose registers, except for the address expansion registers V, U, T, and W, are mapped to the
internal RAM.
Figure 3-1. Configuration of General-Purpose Register
A (R1)
X (R0)
AX (RP0)
B (R3)
C (R2)
BC (RP1)
R5
R4
RP2
R7
R6
RP3
V
R9
R8
VP (RP4)
VVP (RG4)
U
R11
R10
UP (RP5)
UUP (RG5)
T
D (R13)
E (R12)
DE (RP6)
TDE (RG6)
W
H (R15)
L (R14)
WHL (RG7)
HL (RP7)
( ): absolute name
8 banks
Caution Although R4, R5, R6, R7, RP2, and RP3 can be used as X, A, C, B, AX, and BC registers,
respectively, by setting the RSS bit of PSW to 1, do not use this function. The function of the
RSS bit is planned to be deleted from the future models in the 78K/IV Series.
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Data Sheet U12255EJ2V1DS