10
10-89
Ver.0.10
MULTIJUNCTION TIMERS
10.3 TOP (Output-related 16-bit Timer)
(3) Precautions to be observed when using TOP single-shot output mode
The following describes precautions to be observed when using TOP single-shot output mode.
• If the counter stops due to underflow in the same clock period as the timer is enabled by
external input, the former has priority (so that the counter stops).
• If the counter stops due to underflow in the same clock period as count is enabled by writing to
the enable bit, the latter has priority (so that count is enabled).
• If the timer is enabled by external input in the same clock period as count is disabled by writing
to the enable bit, the latter has priority (so that count is disabled).
• Because the internal circuit operation is synchronized to the count clock (prescaler output), a
finite time equal to a prescaler delay is included before F/F starts operating after the timer is
enabled.
Figure 10.3.13 Prescaler Delay
• When writing to the correction register, be careful not to cause the counter to overflow. Even
when the counter overflows due to correction of counts, no interrupt is generated for the
occurrence of overflow. When the counter underflows in the subsequent down-count after
overflow, a false underflow interrupt is generated due to overcounting.
In the example below, the reload register has the initial value H'FFF8 set in it. When the timer
starts, the reload register value is loaded into the counter causing it to start counting down. In the
example diagram here, H'0014 is written to the correction register when the counter has counted
down to H'FFF0. As a result of this correction, the count overflows to H'0004 and fails to count
correctly. Also, an interrupt is generated for an erroneous overcount.
Internal clock
Count clock
Enable
F/F operation
Prescaler cycle
Delay till prescaler
cycle
Write to enable bit
~ ~
~ ~
~ ~
~ ~
Содержание M32170F3VFP
Страница 19: ...CHAPTER 1 CHAPTER 1 OVERVIEW 1 1 Outline of the 32170 1 2 Block Diagram 1 3 Pin Function 1 4 Pin Layout ...
Страница 42: ...1 1 24 Ver 0 10 OVERVIEW 1 4 Pin Layout This is a blank page ...
Страница 56: ...2 2 14 Ver 0 10 This is a blank page ...
Страница 88: ...3 3 32 Ver 0 10 ADDRESS SPACE 3 7 Notes on Address Space This is a blank page ...
Страница 192: ...6 6 58 Ver 0 10 INTERNAL MEMORY 6 9 Precautions to Be Taken When Rewriting Flash Memory This is a blank page ...
Страница 270: ...9 9 40 Ver 0 10 DMAC 9 4 Precautions about the DMAC This is a blank page ...
Страница 498: ...10 10 228 Ver 0 10 MULTIJUNCTION TIMERS 10 9 TOM Output related 16 bit Timer This is a blank page ...
Страница 550: ...11 11 52 Ver 0 10 A D CONVERTERS 11 4 Precautions on Using A D Converters This is a blank page ...
Страница 614: ...12 12 64 Ver 0 10 This is a blank page SERIAL I O 12 9 Precautions on Using UART Mode ...
Страница 710: ...14 14 16 Ver 0 10 REAL TIME DEBUGGER RTD 14 4 Typical Connection with the Host This is a blank page ...
Страница 746: ...16 16 20 Ver 0 10 WAIT CONTROLLER 16 3 Typical Operation of the Wait Controller This is a blank page ...
Страница 756: ...17 17 10 Ver 0 10 RAM BACKUP MODE 17 4 Exiting RAM Backup Mode Wakeup This is a blank page ...
Страница 757: ...CHAPTER 18 CHAPTER 18 OSCILLATION CIRCUIT 18 1 Oscillator Circuit 18 2 Clock Generator Circuit ...
Страница 762: ...18 18 6 Ver 0 10 OSCILLATION CIRCUIT 18 2 Clock Generator Circuit This is a blank page ...
Страница 798: ...19 19 36 Ver 0 10 JTAG 19 6 Precautions about Board Design when Connecting JTAG This is a blank page ...
Страница 830: ...21 21 24 Ver 0 10 PRELIMINARY PRELIMINARY This is a blank page ELECTRICAL CHARACTERISTICS 21 5 AC Characteristics ...
Страница 831: ...CHAPTER 22 CHAPTER 22 TYPICAL CHARACTERISTICS 22 1 A D Conversion Characteristics ...
Страница 833: ...Appendix 1 1 Dimensional Outline Drawing APPENDIX 1 APPENDIX 1 MECHANICAL SPECIFICATIONS ...
Страница 837: ...Appendix 2 1 32170 Instruction Processing Time APPENDIX 2 APPENDIX 2 INSTRUCTION PROCESSING TIME ...
Страница 841: ...Appendix 3 1 Precautions about Noise APPENDIX 3 APPENDIX 3 PRECAUTIONS ABOUT NOISE ...