UPD784026 Renesas Electronics Corporation., UPD784026 Datasheet - Page 533

• Manufacturer Part Number: UPD784026
• Description: 16/8-bit Single-chip Microcontrollers
• Manufacturer: Renesas Electronics Corporation.

macro service (see Table 20-1). These three processing modes can be set as required in the program. However interrupt
processing by macro service can only be selected for interrupt request sources provided with the macro service processing
mode shown in Table 20-2. Context switching cannot be selected for non-maskable interrupts or operand error interrupts.
Vectored interrupts
Context switching
Macro service
Interrupt Request
Processing Mode
The PD784026 is provided with three interrupt request processing modes, vectored interrupt, context switching, and
Multiple-interrupt control using 4 priority levels can easily be performed for maskable vectored interrupts.
* The start addresses of all interrupt service programs must be in the base area. If the body of a service program cannot
be located in the base area, a branch instruction to the service program should be written in the base area.
Processing Performed
(firmware)
Hardware
Software
Table 20-1 Interrupt Request Service Modes
CHAPTER 20 INTERRUPT FUNCTIONS
Saving to & restoration
from stack
Saving to & restoration
from fixed area in
register bank
Retained
PC & PSW Contents
Executed by branching to service program at
address* specified by vector table
Executed by automatic switching to register
bank specified by vector table and branching
to service program at address* specified by
fixed area in register bank
Execution of pre-set processing such as data
transfers between memory and I/O
Service
493