16
16-8
Rev.1.0
16.2.1 Prescaler Unit
The Prescaler PRSA consists of an 8-bit counter which generates a clock from the internal
peripheral clock (20.0 MHz when the CPU clock = 40 MHz) for supply to the DACNT Counter.
The prescaler value is initialized to H'00 when reset.
Also when the value of the prescaler register is rewritten, the prescaler starts operating with the
new value simultaneously when the prescaler underflows.
Any value in the range of H'00 to H'FF can be set in the prescaler register. The prescaler's divide
ratio is given by the equation below.
f
Prescaler set value + 1
Prescaler divide ratio =
■
Prescaler Register A (PRSA)
<Address: H'0080 1800>
D0
1
2
3
4
5
6
D7
PRSA
<When reset: H'00>
D
Bit Name
Function
R
W
0-7
PRSA
Sets the prescaler's divide-by value
The Prescaler A generates a count clock for the D-A converter's parameter table address counter
(DACNT) from the internal peripheral clock (20.0 MHz when the CPU clock = 40 MHz) by dividing it
by an appropriate value. When the value of Prescaler Register A is rewritten while the DACNT is
operating, the prescaler starts operating with the newly set value simultaneously when it
underflows after reaching the minimum count.
The PRSA starts generating a clock after the DACNT Control Register DACNTEN bit is set to 1.
DACNT count period = f / (PRSA + 1)
Note: When using the D-A converter along with PD sensors, the PRSA set value is subject to
limitations depending on how the Position Detection Accuracy Select Register is set.
D-A CONVERTERS
16.2 D-A Converter Related Registers
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 ...