4
4-8
EIT
32180 Group User’s Manual (Rev.1.0)
4.5 Acceptance of EIT Events
When an EIT event occurs, the CPU suspends the program it has hitherto been executing and branches to EIT
processing by the relevant handler. Conditions under which each EIT event occurs and the timing at which they are
accepted are shown below.
Table 4.5.1 Acceptance of EIT Events
EIT Event
Type of Processing
Acceptance Timing
Values Set in BPC Register
Reserved Instruction
Instruction processing-
During instruction execution
PC value of the instruction that
Exception (RIE)
canceled type
generated RIE
Address Exception (AE)
Instruction processing-
During instruction execution
PC value of the instruction that
canceled type
generated AE
Floating-Point Exception
Instruction processing-
Break in instructions
PC value of the instruction that
(FPE)
completed type
generated FPE + 4
Reset Interrupt (RI)
Instruction processing-
Each machine cycle
Undefined value
aborted type
System Break Interrupt
Instruction processing-
Break in instructions
PC value of the next instruction
(SBI)
completed type
(word boundary only)
External Interrupt (EI)
Instruction processing-
Break in instructions
PC value of the next instruction
completed type
(word boundary only)
Trap (TRAP)
Instruction processing-
Break in instructions
PC value of TRAP instr 4
completed type
4.6 Saving and Restoring the PC and PSW
The following describes operation of the microcomputer at the time when it accepts an EIT and when it executes the
RTE instruction.
(1) Hardware preprocessing when an EIT is accepted
[1] Save the PSW register’s SM, IE and C bits in its backup field.
BSM
←
SM
BIE
←
IE
BC
←
C
[2] Update the PSW register’s SM, IE and C bits
SM
←
Remains unchanged (RIE, AE, FPE, TRAP) or cleared to "0" (SBI, EI, RI)
IE
←
Cleared to "0"
C
←
Cleared to "0"
[3] Save the PC register
BPC
←
PC
[4] Set the vector address in the PC register
Branches to the EIT vector and executes the branch (BRA) instruction written in it, thereby transferring
control to the user-created EIT handler.
(2) Hardware postprocessing when the RTE instruction is executed
[A] Restore the PSW register’s SM, IE and C bits from its backup field.
SM
←
BSM
IE
←
BIE
C
←
BC
[B] Restore the PC register from the BPC register.
PC
←
BPC
Note: • The values stored in the BPC and the PSW register’s BSM, BIE and BC bits after executing the RTE
instruction are undefined.
4.5 Acceptance of EIT Events
Summary of Contents for M32R/ECU Series
Page 17: ...12 This page is blank for reasons of layout...
Page 712: ...CHAPTER 18 OSCILLATOR CIRCUIT 18 1 Oscillator Circuit 18 2 Clock Generator Circuit...
Page 794: ...CHAPTER 22 TYPICAL CHARACTERISTICS...
Page 796: ...APPENDIX 1 MECHANICAL SPECIFICAITONS Appendix 1 1 Dimensional Outline Drawing...
Page 798: ...APPENDIX 2 INSTRUCTION PROCESSING TIME Appendix 2 1 32180 Instruction Processing Time...
Page 802: ...APPENDIX 3 PROCESSING OF UNUSED PINS Appendix 3 1 Example Processing of Unused Pins...