CHAPTER 4 INTERNAL CPU FUNCTION
61
User’s Manual U10676EJ3V0UM
4.1.2 Setting stack bank select register (SBS)
The MkI mode or MkII mode is selected by using the stack bank select register (SBS). Figure 4-1 shows the format
of this register.
The stack bank select register is set by using a 4-bit memory manipulation instruction. To use the MkI mode, be
sure to initialize the stack bank select register to 1000B at the beginning of the program. To use the MkII mode, initialize
the register to 0000B.
Figure 4-1. Format of Stack Bank Select Register
3
2
Address
1
0
0
Memory bank 0
SBS
SBS0
F84H
SBS1
SBS3
SBS2
Symbol
Specifies stack area
0
Other than above, setting prohibited
0
Be sure to set bit 2 to 0.
0
Mkll mode
Selects mode
1
Mkl mode
Caution The SBS.3 bit is set to “1” after the RESET signal has been asserted. Therefore, the CPU operates
in the MkI mode. To use the instructions in the MkII mode, clear SBS.3 to “0” to set the MkII mode.