
3-3
ML63326 User's Manual
Chapter 3 CPU Control Functions
3
3.3 Halt Mode
3.3.1 Transfer to and State of Halt Mode
Transfer to the halt mode is performed by the software when a HALT instruction is executed.
When a HALT instruction is executed, the CPU enters the HALT mode at the S2 state of the
HALT instruction.
Oscillation and time base counter operation continue while in the halt mode.
If an interrupt request occurs at the same time as execution of a HALT instruction, interrupt
processing has priority and the HALT instruction will not be executed. After the HALT
instruction performs the equivalent operation of a NOP instruction, the interrupt routine is
entered. When an RTI instruction is used to complete the interrupt routine, the main routine
is resumed beginning from the instruction immediately following the HALT instruction.
Figure 3-4 shows the timing when a HALT instruction and interrupt request occur simultane-
ously.
S1
S2
S1
S2
S1
S2
S2
S1
S2
S1
S2
S1
S2
S1
S2
HALT
HALT
instruction
execution
RTI instruction
execution
HLT (halt flag)
Interrupt request
INT
PC flow in main
routine
: HALT instruction address
: Starting address of interrupt routine
: RTI instruction address
(equivalent
to NOP)
Interrupt routine
Main
routine
System clock
n
n+1
n+2
(INT)
(RTI)
n
(INT)
(RTI)
Figure 3-4 Timing of Simultaneous HALT Instruction and Interrupt Request
!
Note:
While an interrupt request is generated, execution of a HALT instruction will not transfer
operation to the halt mode.
Summary of Contents for ML63326
Page 3: ......
Page 13: ......
Page 14: ...Chapter 1 Overview 1 ...
Page 15: ......
Page 37: ...1 22 ML63326 User s Manual Chapter 1 Overview ...
Page 38: ...Chapter 2 CPU and Memory Spaces 2 ...
Page 39: ......
Page 50: ...CPU Control Functions Chapter 3 3 ...
Page 51: ......
Page 57: ...3 6 ML63326 User s Manual Chapter 3 CPU Control Functions ...
Page 58: ...Interrupt INT326 Chapter 4 4 ...
Page 59: ......
Page 71: ...4 12 ML63326 User s Manual Chapter 4 Interrupt INT326 ...
Page 72: ...Clock Generator Circuit OSC Chapter 5 5 ...
Page 73: ......
Page 83: ...5 10 ML63326 User s Manual Chapter 5 Clock Generator Circuit OSC ...
Page 84: ...Time Base Counter TBC Chapter 6 6 ...
Page 85: ......
Page 90: ...Timers TIMER Chapter 7 7 ...
Page 91: ......
Page 115: ...7 24 ML63326 User s Manual Chapter 7 Timers TIMER ...
Page 116: ...Chapter 8 8 100 Hz Timer Counter 100HzTC ...
Page 117: ......
Page 121: ...8 4 ML63326 User s Manual Chapter 8 100 Hz Timer Counter 100HzTC ...
Page 122: ...Chapter 9 9 Watchdog Timer WDT ...
Page 123: ......
Page 128: ...Chapter 10 10 Ports INPUT OUTPUT I O PORT ...
Page 129: ......
Page 170: ...Chapter 11 11 External Memory Transfer Function EXTMEM ...
Page 171: ......
Page 179: ...11 8 ML63326 User s Manual Chapter 11 External Memory Transfer Function EXTMEM ...
Page 180: ...Chapter 12 12 Melody Driver MELODY63K ...
Page 181: ......
Page 195: ...12 14 ML63326 User s Manual Chapter 12 Melody Driver MELODY63K ...
Page 196: ...13 Chapter 13 Voice Synthesis ...
Page 197: ......
Page 228: ...14 Chapter 14 Shift Register SFT ...
Page 229: ......
Page 236: ...15 Chapter 15 LCD Driver LCD ...
Page 237: ......
Page 250: ...16 Chapter 16 Battery Low Detect Circuit BLD ...
Page 251: ......
Page 255: ...16 4 ML63326 User s Manual Chapter 16 Battery Low Detect Circuit BLD ...
Page 256: ...Chapter 17 17 Power Supply Circuit POWER ...
Page 257: ......
Page 260: ...Appendixes ...
Page 261: ......
Page 321: ...Appendix 60 ML63326 User s Manual Appendix G ...