UPD784218 Datasheet, PDF (24/92 Pages) NEC – 16-/8-BIT SINGLE-CHIP MICROCONTROLLERS

µPD784218, 784218Y
7.2 CPU Registers
7.2.1 General-purpose registers
Sixteen 8-bit general-purpose registers are available. Two 8-bit registers can be also used in pairs as a 16-bit
register. Of the 16-bit registers, four can be used in combination with an 8-bit register for address expansion as
24-bit address specification registers.
Eight banks of these register sets are available and can be selected by using software or the context switching
function.
The general-purpose registers except the V, U, T, and W registers for address expansion are mapped to the
internal RAM.
Figure 7-2. General-Purpose Register Format
A (R1)
X (R0)
AX (RP0)
B (R3)
C (R2)
BC (RP1)
R5
R4
RP2
R7
R6
RP3
V
R9
R8
VVP (RG4)
VP (RP4)
U
R11
R10
UUP (RG5)
UP (RP5)
T
D (R13)
E (R12)
TDE (RG6)
DE (RP6)
W
H (R15)
L (R14)
WHL (RG7)
HL (RP7)
Parentheses ( ) indicate an absolute name.
8 banks
Caution
Registers R4, R5, R6, R7, RP2, and RP3 can be used as the X, A, C, B, AX, and BC registers,
respectively, by setting the RSS bit of the PSW to 1. However, use this function only for recycling
the program of the 78K/III Series.
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Data Sheet U12304EJ2V0DS00