DS_1209F_004
73S1209F Data Sheet
Rev. 1.2
21
1.5.3 External Data Special Function Registers (SFRs)
A map of the XRAM Special Function Registers is shown in Table 6. . The smart card registers are listed
separately in Table 108.
Table 8: XRAM Special Function Registers Reset Values
Name Location
Reset
Value
Description
0x FF80 0x00
Device Address Register (I
2
C)
0x FF81 0x00
Write Data Register (I
2
C)
0x FF82 0x00
Secondary Write Data Register (I
2
C)
0x FF83 0x00
Read Data Register (I
2
C)
0x FF84 0x00
Secondary Read Data Register (I
2
C)
0x FF85 0x00
Control and Status Register (I
2
C)
External Interrupt Control 1
External Interrupt Control 2
External Interrupt Control 3
External Interrupt Control 4
0x FF94 0x00
External Interrupt Control 5
0x FF95 0x00
External Interrupt Control 6
0x FFA1 0x0C
MPU Clock Control
0x FFD0 0x00
Analog Compare Register
0x FFD1 0x00
TRIM Pulse Control
0x FFD2 0x00
FUSE Control
0x FFD4 0x00
VDDFault Control
0x FFD7 0x00
Security Register
0x FFF1 0x00
Miscellaneous Control Register 0
0x FFF2 0x10
Miscellaneous Control Register 1
0x FFF3 0xFF
LED Control Register
Accumulator (ACC, A):
ACC is the accumulator register. Most instructions use the accumulator to hold
the operand. The mnemonics for accumulator-specific instructions refer to accumulator as “A”, not ACC.
B Register:
The B register is used during multiply and divide instructions. It can also be used as a
scratch-pad register to hold temporary data.