UPD784026 Renesas Electronics Corporation., UPD784026 Datasheet - Page 568

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

20.8 MACRO SERVICE FUNCTION
20.8.1 Outline of Macro Service Function
status word (PSW) are saved, and the start address of the interrupt service program is loaded into the PC, but with macro
service, different processing (mainly data transfers) is performed instead of this processing. This enables interrupt requests
to be responded to quickly, and moreover, since transfer processing is faster than processing by a program, the processing
time can also be reduced.
advantage is that vectored interrupt programs can be simplified.
20.8.2 Types of Macro Service
There are four kinds of operation, which can be used to suit the application.
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Context Switching*
Vectored Interrupt*
Vectored Interrupt
Macro service is one method of processing interrupts. With a normal interrupt, the program counter (PC) and program
Also, since a vectored interrupt is generated after processing has been performed the specified number of times, another
* 1. When register bank switching is used, and an initial value has been set in the register beforehand
Macro service can be used with the 19 kinds of interrupt shown in Table 20-6 (17 of which can be used simultaneously).
2. Register bank switching by context switching, saving of PC and PSW
3. Register bank, PC and PSW restoration by context switching
4. PC and PSW saved to the stack, vector address loaded into PC
Macro Service
Figure 20-16 Differences between Vectored Interrupt and Macro Service Processing
1
1
Main Routine
Main Routine
Main Routine
Main Routine
Interrupt Request Generation
CHAPTER 20 INTERRUPT FUNCTIONS
Macro Service
Processing
*2
*4
*4
RBn
SEL
Registers
General
Save
Processing
Interrupt
Main Routine
Processing
Interrupt
Registers
Initialize
General
*3
Processing
Interrupt
PC, PSW
Restore
Main Routine
Main Routine
Registers
Restore
General
PC & PSW
Restore
Main Routine