Setting Method Of Stack Bank Select Register (Sbs) - NEC MuPD754144 Datasheet

4.2 Setting Method of Stack Bank Select Register (SBS)

Switching between the Mk I mode and Mk II mode can be done by the SBS. Figure 4-1 shows the format.
The SBS is set by a 4-bit memory manipulation instruction.
When using the Mk I mode, the SBS must be initialized to 1000B at the beginning of a program. When using
the Mk II mode, it must be initialized to 0000B.
Address
F84H
Caution Because SBS. 3 is set to "1" after a RESET signal is generated, the CPU operates in the
Mk I mode. When executing an instruction in the Mk II mode, set SBS. 3 to "0" to select
the Mk II mode.
14
Figure 4-1. Stack Bank Select Register Format
Symbol
3 2 1 0
SBS3 SBS2 SBS1 SBS0
Data Sheet U10040EJ2V1DS
SBS
Stack area specification
Memory bank 0
0 0
Other than above setting prohibited
0 0 must be set in the bit 2 position
Mode switching specification
0 Mk II mode
1 Mk I mode
*
µ PD754144, 754244