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9-50
Rev.1.0
9.3.3 Starting DMA
Use the REQSL (cause of DMA request select) bits to select the cause of DMA request. To enable
DMA, set the TENL (DMA transfer enable) bit to 1. A DMA transfer starts when the selected cause
of DMA request becomes effective after setting the TENL (DMA transfer enable) bit to 1.
Note: If the request source specified with the REQSL (DMA request source select) bit is an input/
output timer (TIN input signal), the time required for DMA transfer to start after detecting
the rising or falling edge or both edges of the TIN input signal is three cycles at the least
(150 ns when operating with the internal peripheral clock = 20 MHz). Or, depending on the
bus usage condition before or after the DMA transfer, up to six cycles may be required
(300 ns when operating with the internal peripheral clock = 20 MHz). (The above required
time for DMA transfer to start after detecting the TIN input signal is calculated assuming
that the external bus is unused, and that HOLD and the LOCK instruction are not used.)
To ensure that changes of state of the TIN input signal will be detected correctly, make
sure the TIN input signal has a pulse width of at least 7tc(BCLK)/2. (For details, see
Section 23.6, "AC Characteristics.")
9.3.4 Priority of DMA Channels
DMA channel 0 has the highest priority, which is followed by other channels as shown below. The
channel priority is fixed.
Channel 0 > channel 1 > channel 2 > channel 3 > channel 4 > channel 5 >
channel 6 > channel 7 > channel 8 > channel 9 >
Transfer requests on channels are sampled every transfer cycle (= three DMA bus cycles), and the
channel that has the highest priority among those which have transfer requests generated is
selected.
DMAC
9.3 Functional Description of DMAC
Содержание 32172
Страница 20: ... This is a blank page 16 ...
Страница 21: ...1 1 Overview 1 2 Block Diagram 1 3 Pin Functions 1 4 Pin Layout CHAPTER 1 CHAPTER 1 OVERVIEW ...
Страница 44: ...1 1 24 Rev 1 0 This is a blank page Overview 1 4 Pin Layout ...
Страница 58: ...2 2 14 Rev 1 0 This is a blank page CPU 2 6 Data Formats ...
Страница 122: ...4 4 26 Rev 1 0 This is a blank page EIT 4 13 Precautions on EIT ...
Страница 200: ...7 7 6 Rev 1 0 This is a blank page RESET 7 4 Precautions to Be Taken Immediately after Reset ...
Страница 240: ...8 8 40 Rev 1 0 This is a blank page INPUT OUTPUT PORTS AND PIN FUNCTIONS 8 5 Precautions on Input Output Ports ...
Страница 298: ...9 9 58 Rev 1 0 This is a blank page DMAC 9 4 Precautions on Using DMAC ...
Страница 416: ...10 10 118 Rev 1 0 This is a blank page INPUT OUTPUT TIMERS 10 6 TOM Output Related 16 bit Timers ...
Страница 658: ...14 14 16 Rev 1 0 REAL TIME DEBUGGER RTD 14 4 Typical Connection with the Host This is a blank page ...
Страница 718: ...16 16 16 Rev 1 0 This is a blank page D A CONVERTERS 16 3 Functional Description of the D A Converters ...
Страница 766: ...18 18 22 Rev 1 0 WAIT CONTROLLER 18 3 Typical Operation of the Wait Controller This is a blank page ...
Страница 776: ...19 19 10 Rev 1 0 RAM BACKUP MODE 19 4 Exiting RAM Backup Mode Wakeup This is a blank page ...
Страница 777: ...CHAPTER 20 CHAPTER 20 OSCILLATION CIRCUIT 20 1 Oscillator Circuit 20 2 Clock Generator Circuit ...
Страница 782: ...20 20 6 Rev 1 0 OSCILLATION CIRCUIT 20 2 Clock Generator Circuit This is a blank page ...
Страница 856: ...23 23 26 Rev 1 0 This is a blank page ELECTRICAL CHARACTERISTICS 23 6 AC Characteristics ...
Страница 857: ...24 1 A D Conversion Characteristics CHAPTER 24 CHAPTER 24 STANDARD CHARACTERISTICS ...
Страница 859: ...Appendix 1 1 Dimensional Outline Drawing APPENDIX 1 APPENDIX 1 MECHANICAL SPECIFICATIONS ...
Страница 861: ...Appendix 2 1 M32R E Instruction Processing Time APPENDIX 2 APPENDIX 2 INSTRUCTION PROCESSING TIME ...
Страница 865: ...Appendix 3 1 Precautions about Noise APPENDIX 3 APPENDIX 3 PRECAUTIONS ABOUT NOISE ...