UPD78323 NEC, UPD78323 Datasheet - Page 21

• Manufacturer Part Number: UPD78323
• Description: 16/8-BIT SINGLE-CHIP MICROCONTROLLER
• Manufacturer: NEC

(3) Stack pointer (SP)
from the stack memory.
This is a 16-bit register which holds the first address of the stack area (LIFO format) of the memory.
It is operated by a dedicated instruction.
SP is decremented before write (save) operation into the stack memory and is incremented after read (return) operation
Since SP becomes indeterminate by RESET input, it must be set before subroutine call.
(f)
(g) Register set select flag (RSS)
(h) Interrupt request enable flag (IE)
(i)
(j)
In all other cases, this flag is reset to 0. This flag can be tested by the conditional branch instruction.
relationship between the functional register and the absolute register.
is reset to 0 byexecution of DI instruction or acceptance of an interrupt.
If a carry is generated out of bit 3 as a result of operation or a borrow is generated into bit 3, this flag is set to 1.
This flag is used to specify general registers X, A, C and B. As shown in Table 2-1, the RSS value determines the
Thus, another register set (X, A, C, B) can be used by switching the RSS flag.
This flag is used to indicate interrupt request enable/disable. This flag is set to 1 by execution of EI instruction and
This is a 3-bit flag to select one of eight register banks (RBANK0 to RBANK7).
This flag is set or reset in the user program and can be used for program control.
Auxiliary carry flag (AC)
Register bank select flag (RBS0 to RBS2)
User flag (UF)
PD78323, 78324
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