UPD78323 NEC, UPD78323 Datasheet - Page 44

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

44
4.3
executing BRKCS instruction, to branch the selected register bank to the vector address prestored in the register bank, and
also to stack the current PC and PSW contents into the register bank.
4.3.1
the register bank which is specified by the lower 3 bits of the lower address (even address) of the corresponding interrupt
vector table address is selected. The vector address prestored in the selected register bank is transferred to the PC, the
PC and PSW contents are saved into the register bank, and the operation is branched to the interrupt processing routine.
This is the function to first select the specified register bank in hardware terms by generating an interrupt request or
The context switching function start is enabled by setting the
If an unmasked interrupt request for which the context switching function has been enabled is generated in the EI state,
Return is by means of executing the RETCS instruction.
CONTEXT SWITCHING FUNCTION
Context Switching Function at Interrupt Request
PSW
PC
Exchange
Save
Figure 4-3. Context Switching at Interrupt Request
RBANK n
A
B
R5
R7
D
H
VP
UP
X
C
R4
R6
E
L
CSE bit preset at each interrupt request to 1.
Register
Banks
(0 to 7)
PD78323, 78324