1. Lecture 13 A/D Converter & D/A Converter

2. Outline Basic Operation Single Scan Mode Continuous Scan Mode
Group Scan Mode
Interrupt Sources
Registers
D/A Converter

3. The microcontroller can process only digital data
Need
The microcontroller can process only digital data
Are the following commonly measured quantities analog or digital ?
Distance
Weight
Acceleration
Temperature
All physical quantities are analog. The world is analog !
We need to convert these analog values to digital for the microcontroller to comprehend the value of the real analog physical quantity

4. Reference voltage
The analog value is compared with a known reference voltage to obtain its digital form
The measurement process is called quantization

5. Resolution
The number of bits in the digital output is called the resolution of the ADC
A 12-bit A/D convertor can produce 2^12 = 4096 distinct digital outputs

6. Successive Approximation
RX210 microcontroller employs this method of conversion
In this method, initially the microcontroller compares the analog voltage with half the reference voltage
In each approximation step, the microcontroller halves the possible range between which the digital value lies
In this way the microcontroller closes in on the analog value, setting 1 or 0 to the bit position starting from MSB
Set 1 if the analog value is greater than the reference value of that step, else set to 0

7. Successive Approximation (cont.)
Consider 2.5V to be measured with Vref= 3.3V using 10- bit A/D converter
First 2.5 is compared with 1.65 (mean of 0 & 3.3) . Since 2.5>1.65, our digital value is 1xxxxxxxxx
Next compare 2.5 with 2.47 (mean of 1.65 & 3.3) . Since 2.5>2.47, our digital value is 11xxxxxxxx
We proceed in similar way till we get the lsb of the digital form
We compare ‘n’ times, where ‘n’ is the resolution of the A/D converter

8. Transfer function n= digital output Vin = input analog voltage
V+ref = upper reference voltage
V-ref = lower reference voltage, generally zero
N = resolution of A/D converter

9. Conversion speed Conversion speed = Start delay(tD) + input sampling
Time (tSPL) + conversion time (tSAM)

10. 12-bit ADC registers Some of the important registers are:
A/D Data Registers
(ADDRn) (n = 0 to 15)
16-bit register
Holds the digital value
To use a particular channel, the respective port has to be set up as input. For example, to use AN0, port 4 pin 0 use:
PORT4.PDR.BIT.B0 = 0;
For inputs, the Port Mode Register (PMR) also has to set up. This can be done using:
PORT4.PMR.BIT.B0 = 1;

11. The A/D converter has three operating modes
Overview
The RX210 Group includes a 12-bit successive approximation A/D converter
Up to 16 channel analog inputs, temperature sensor outputs, or internal reference voltages can be selected
Into a 12-bit digital value through successive approximation
The A/D converter has three operating modes
Single scan mode
The analog inputs of up to 16 arbitrarily selected channels are converted for only once in ascending channel order
Continuous scan mode
The analog inputs of up to 16 arbitrarily selected channels are continuously converted in ascending channel order
Group scan mode
Up to 16 channels of the analog inputs are arbitrarily divided into two groups: Group A and group B
Converted in ascending channel order in each group

12. Self-diagnosis is executed once at the beginning of each scan
Overview (cont.)
In group scan mode, the scan start conditions of group A and group B can be independently selected
Allowing A/D conversion of group A and group B to be started independently
In double trigger mode
One arbitrarily selected analog input channel is converted in single scan mode or group scan mode (group A)
The resulting data of A/D conversion started by the first and second triggers are stored into separate registers
Duplication of A/D conversion data
Self-diagnosis is executed once at the beginning of each scan
One of the three voltages internally generated in the 12-bit A/D converter is converted
A/D conversion of the temperature sensor output or the internal reference voltage is accomplished independently

14. Scanning Operation
A/D conversion is performed sequentially on the analog inputs of the specified channels
In continuous scan mode, one or more specified channels are scanned repeatedly
Until the ADST bit in ADCSR is cleared to 0 from 1 by software
In group scan mode, the selected channels of group A and the selected channels of group B are scanned once
After starting to be scanned according to the respective triggers
In single scan mode and continuous scan mode, A/D conversion is performed for ANn channels selected
By the ADANSA register, starting from the channel with the smallest number n
In group scan mode, A/D conversion is performed for ANn channels of group A and group B selected
By the ADANSA and ADANSB registers, respectively, starting from the channel with the smallest number n

15. Scanning Operation (cont.)
When the temperature sensor output or the internal reference voltage is selected
Single scan mode should be used for A/D conversion
Double trigger mode is to be used with single scan mode or group scan mode
A/D conversion data of a channel selected by the DBLANS[4:0] bits in ADCSR is duplicated
Only if the conversion is started by any of the MTU or ELC (Event Link Controller) triggers selected by TRSA[3:0] bits in ADSTRGR
ELC connects (links) the events generated by various peripheral modules to different modules
When any of AN000 to AN002 channels is set by the SHANS[2:0] bits in ADSHCR
The channel uses a channel-dedicated sample-and-hold circuit
The set analog input is sampled and held before the first A/D conversion of each scan

16. Sample and Hold circuit
This circuit catches hold of the voltage to be converted to digital form
It is helpful particularly when the input analog voltage varies very fast
When the switch is closed, the capacitor charges to the value of analog voltage and that value is fed to the A/D converter

17. Single Scan Mode
Basic operation with channel-dedicated sample-and-hold circuits not used
A/D conversion is performed once on the analog input of the specified channels
Temperature sensor output A/D conversion select bit (TSS) and internal reference voltage A/D conversion select bit (OCS) in ADEXICR should both be set to 0 (non-selection)
A/D conversion is performed for ANn channels selected by the ADANSA register
When the ADST bit in ADCSR is set to 1 (A/D conversion start) by software, synchronous trigger (MTU or ELC), or asynchronous trigger input
Each time A/D conversion of a single channel is completed
The A/D conversion result is stored into the corresponding A/D data register (ADDRy)
When A/D conversion of all the selected channels is completed
An S12ADI0 interrupt request is generated
If the ADIE bit in ADCSR is 1 (interrupt upon scanning completion)

18. Single Scan Mode (cont.)
The ADST bit remains 1 (A/D conversion start) during A/D conversion
Automatically cleared to 0 when A/D conversion of all the selected channels is completed
The 12-bit A/D converter enters a wait state

19. Single Scan Mode (cont.)
Basic operation with channel-dedicated sample-and-hold circuits used
Sample-and-hold operation is first performed
Then A/D conversion is performed once on the analog input of all the selected channels
The channels whose channel-dedicated sample-and-hold circuit is to be used can be selected by SHANS[2:0] bits in ADSHCR
Temperature sensor output A/D conversion select bit (TSS) and internal reference voltage A/D conversion select bit (OCS) in ADEXICR should both be set to 0 (non-selection)
Analog input sampling of all the channels whose channel- dedicated sample-and-hold circuit is to be used is started
When the ADST bit in ADCSR is set to 1 (A/D conversion start) by software, synchronous trigger (MTU or ELC), or asynchronous trigger input
After sample-and-hold operation, A/D conversion is performed for ANn channels selected by the ADANSA register

20. Single Scan Mode (cont.)
Starting from the channel with the smallest number n
Each time A/D conversion of a single channel is completed
The A/D conversion result is stored into the corresponding A/D data register (ADDRy)
When A/D conversion of all the selected channels is completed
An S12ADI0 interrupt request is generated
If the ADIE bit in ADCSR is 1 (interrupt upon scanning completion)
The ADST bit remains 1 (A/D conversion start) during A/D conversion
Automatically cleared to 0 when A/D conversion of all the selected channels is completed
The 12-bit A/D converter enters a wait state

21. Single Scan Mode (cont.)
Example of operation in single scan mode
Channel-dedicated sample-and-hold circuits used
Basic operation: AN000 to AN002 selected

22. Single Scan Mode (cont.)
Channels selection and self-diagnosis (channel-dedicated sample-and-hold circuits not used)
A/D conversion is first performed for the self-diagnosis voltage
VREFH0 × 0, VREFH0 × 1/2, or VREFH0 × 1 generated from the reference power supply voltage (VREFH0) supplied to the 12-bit A/D converter
A/D conversion is performed once on the analog input of the selected channels
Temperature sensor output A/D conversion select bit (TSS) and internal reference voltage A/D conversion select bit (OCS) in ADEXICR should both be set to 0 (non-selection)
A/D conversion for self-diagnosis is first started
When the ADST bit in ADCSR is set to 1 (A/D conversion start) by software, synchronous trigger (MTU or ELC), or asynchronous trigger input
When A/D conversion for self-diagnosis is completed
The A/D conversion result is stored into the A/D self-diagnosis data register (ADRD)

23. Single Scan Mode (cont.)
A/D conversion is then performed for ANn channels selected by the ADANSA register
Starting from the channel with the smallest number n
Each time A/D conversion of a single channel is completed
The A/D conversion result is stored into the corresponding A/D data register (ADDRy)
When A/D conversion of all the selected channels is completed
An S12ADI0 interrupt request is generated
If the ADIE bit in ADCSR is 1 (S12ADI0 interrupt upon scanning completion enabled)
The ADST bit remains 1 (A/D conversion start) during conversion
Automatically cleared to 0 when A/D conversion of all the selected channels is completed
The 12-bit A/D converter enters a wait state

24. Single Scan Mode (cont.)
Example of operation in single scan mode
Basic operation + self-diagnosis

25. Single Scan Mode (cont.)
Channels selection and self-diagnosis (channel-dedicated sample-and-hold circuits used)
Sample-and-hold operation is first performed
A/D conversion is performed once for the self-diagnosis voltage
VREFH0 × 0, VREFH0 × 1/2, or VREFH0 × 1 generated from the reference power supply voltage (VREFH0) supplied to the 12-bit A/D converter
A/D conversion is performed only once on the analog input of the selected channels
Temperature sensor output A/D conversion select bit (TSS) and internal reference voltage A/D conversion select bit (OCS) in ADEXICR should both be set to 0 (non-selection)
Analog input sampling of all the channels whose channel- dedicated sample-and-hold circuit is to be used is started
When the ADST bit in ADCSR is set to 1 (A/D conversion start) by software, synchronous trigger (MTU or ELC), or asynchronous trigger input

26. Single Scan Mode (cont.)
After sample-and-hold operation, A/D conversion for self- diagnosis is started
When A/D conversion for self-diagnosis is completed
The A/D conversion result is stored into the A/D self-diagnosis data register (ADRD)
A/D conversion is then performed for ANn channels selected by the ADANSA register
Starting from the channel with the smallest number n
Each time A/D conversion of a single channel is completed
The A/D conversion result is stored into the corresponding A/D data register (ADDRy)
When A/D conversion of all the selected channels is completed
An S12ADI0 interrupt request is generated
If the ADIE bit in ADCSR is 1 (S12ADI0 interrupt upon scanning completion enabled)
The ADST bit remains 1 during A/D conversion
Automatically cleared to 0 as conversion of all channels is finished
Then the 12-bit A/D converter enters a wait state

27. Single Scan Mode (cont.)
Example of operation in single scan mode
Channel-dedicated sample-and-hold circuits used + self- diagnosis

28. Single Scan Mode (cont.)
A/D conversion of the temperature sensor output
Should be performed in single scan mode
All the channels should be deselected
Set the ANSA[15:0] bits in ADANSA to 0000h and DBLE bit in ADCSR to 0
Self-diagnosis should be deselected
The internal reference voltage A/D conversion select bit (OCS) in ADEXICR should also be set to 0 (non-selection)
A/D conversion is started for the temperature sensor output
When the ADST bit in ADCSR is set to 1 (A/D conversion start) by the trigger from the temperature sensor
When A/D conversion is completed
The A/D conversion result is stored into the A/D temperature sensor data register (ADTSDR)
An S12ADI0 interrupt request is generated
If the ADIE bit in ADCSR is 1 (S12ADI0 interrupt upon scanning completion enabled)

29. Single Scan Mode (cont.)
The ADST bit remains 1 during A/D conversion
Automatically cleared to 0 when A/D conversion is completed
Then the 12-bit A/D converter enters a wait state

30. Single Scan Mode (cont.)
A/D conversion of the internal reference voltage
Should be performed in single scan mode
All the channels should be deselected
Set the ANSA[15:0] bits in ADANSA to 0000h and DBLE bit in ADCSR to 0
Self-diagnosis should be deselected
The temperature sensor output A/D conversion select bit (TSS) in ADEXICR should also be set to 0 (non-selection)
A/D conversion is started for the internal reference voltage
When the ADST bit in ADCSR is set to 1 (A/D conversion start) by software, the synchronous trigger (MTU or ELC), or the asynchronous trigger input
When A/D conversion is completed
The A/D conversion result is stored into the A/D internal reference voltage data register (ADOCDR)
If the ADIE bit in ADCSR is 1 (S12ADI0 interrupt upon scanning completion enabled), an S12ADI0 interrupt request is generated

31. Single Scan Mode (cont.)
The ADST bit remains 1 during A/D conversion
Automatically cleared to 0 when A/D conversion is completed
Then the 12-bit A/D converter enters a wait state

32. Single Scan Mode (cont.)
In single scan mode with double trigger mode
Single scan operation started by the MTU or ELC trigger is performed twice
Self-diagnosis should be deselected
The temperature sensor output A/D conversion select bit (TSS) and internal reference voltage A/D conversion select bit (OCS) in ADEXICR should both be set to 0 (non-selection)
Duplication of A/D conversion data is enabled
By setting the channel numbers to be duplicated to the DBLANS[4:0] bits in ADCSR
Setting the DBLE bit in ADCSR to 1
When the DBLE bit in ADCSR is set to 1, channel selection using the ADANSA register is invalid
MTU or ELC triggers should be selected using the TRSA[3:0] bits in ADSTRGR
The EXTRG bit and TRGE bit in ADCSR should be set to 0 and 1, respectively
Software trigger should not be used

33. Single Scan Mode (cont.)
A/D conversion is started on the single channel selected by the DBLANS[4:0] bits in ADCSR
When the ADST bit in ADCSR is set to 1 (A/D conversion start) by the MTU or ELC trigger input
When A/D conversion is completed
The A/D conversion result is stored into the corresponding A/D data register (ADDRy)
The ADST bit is automatically cleared to 0
The 12-bit A/D converter enters a wait state
An S12ADI0 interrupt request is not generated irrespective of the ADIE (interrupt upon scanning completion) bit setting in ADCSR
When the ADST bit in ADCSR is set to 1 (A/D conversion start) by the second trigger input
The A/D conversion result is stored into the A/D data duplication register (ADDBLDR)

34. Single Scan Mode (cont.)
Exclusively used in double trigger mode
If the ADIE bit in ADCSR is 1, an interrupt request is generated
The ADST bit remains 1 (A/D conversion start) during A/D conversion
Automatically cleared to 0 when A/D conversion is completed
Then the 12-bit A/D converter enters a wait state

35. Continuous Scan Mode
A/D conversion is performed repeatedly on the analog input of the specified channel
The temperature sensor output A/D conversion select bit (TSS) and internal reference voltage A/D conversion select bit (OCS) in ADEXICR should both be set to 0 (non-selection)
The 12-bit A/D converter sequentially starts A/D conversion for ANn channels selected by the ADANSA register
When the ADST bit in ADCSR is set to 1 (A/D conversion start) by software, synchronous trigger (MTU or ELC), or asynchronous trigger input
Starting from the channel with the smallest number n
Each time A/D conversion of a single channel is completed
The A/D conversion result is stored into the corresponding A/D data register (ADDRy)
When A/D conversion of all the selected channels is completed
An S12ADI0 interrupt request is generated
If the ADIE bit in ADCSR is 1

36. Continuous Scan Mode (cont.)
The ADST bit in ADCSR is not automatically cleared to 0
The above steps 2 and 3 are repeated as long as the bit remains 1 (A/D conversion start)
When the ADST bit in ADCSR is set to 0 (A/D conversion stop), A/D conversion stops
The 12-bit A/D converter enters a wait state
When the ADST bit is later set to 1 (A/D conversion start)
A/D conversion is started again for ANn channels selected by the ADANSA register
Starting from the channel with the smallest number n

37. Continuous Scan Mode (cont.)
Example of operation in continuous scan mode
Basic operation: AN000 to AN002 selected

38. Continuous Scan Mode (cont.)
When the channel-dedicated sample-and-hold circuit is used
Sample-and-hold operation is first performed
Then A/D conversion is repeated on the analog input of all the selected channels
The channels whose channel-dedicated sample-and-hold circuit is to be used can be selected by the SHANS[2:0] bits in ADSHCR
Temperature sensor output A/D conversion select bit (TSS) and internal reference voltage A/D conversion select bit (OCS) in ADEXICR should both be set to 0 (non-selection)
Analog input sampling of all the channels whose channel- dedicated sample-and-hold circuit is to be used is started
When the ADST bit in ADCSR is set to 1 (A/D conversion start) by software or synchronous trigger (MTU or ELC) input
After sample-and-hold operation, A/D conversion is performed for ANn channels selected by the ADANSA register
Starting from the channel with the smallest number n
Each time A/D conversion of a single channel is completed

39. Continuous Scan Mode (cont.)
The A/D conversion result is stored into the corresponding A/D data register (ADDRy)
When A/D conversion of all the selected channels is completed
An S12ADI0 interrupt request is generated
If the ADIE bit in ADCSR is 1
At the same time, analog input sampling is started for all the channels whose channel-dedicated sample-and-hold circuit is to be used
The ADST bit is not automatically cleared to 0
The above steps are repeated as long as the bit remains 1
When the ADST bit is set to 0 (A/D conversion stop)
A/D conversion stops
The 12-bit A/D converter enters a wait state
When the ADST bit is later set to 1 (A/D conversion start)
Analog input sampling is started again for all the channels whose channel-dedicated sample-and-hold circuit is to be used

40. Continuous Scan Mode (cont.)
Example of operation in continuous scan mode
Channel-dedicated sample-and-hold circuit is used

41. Continuous Scan Mode (cont.)
Channels selection and self-diagnosis
A/D conversion is first performed for the self-diagnosis voltage
VREFH0 × 0, VREFH0 × 1/2, or VREFH0 × 1 generated from the reference power supply voltage (VREFH0) supplied to the 12-bit A/D converter
Then A/D conversion is performed on the analog input of the selected channels
The temperature sensor output A/D conversion select bit (TSS) and internal reference voltage A/D conversion select bit (OCS) in ADEXICR should both be set to 0 (non-selection)
A/D conversion for self-diagnosis is first started
When the ADST bit in ADCSR is set to 1 (A/D conversion start) by software, synchronous trigger (MTU or ELC), or asynchronous trigger input
When A/D conversion for self-diagnosis is completed
The A/D conversion result is stored into the A/D self-diagnosis data register (ADRD)

42. Continuous Scan Mode (cont.)
A/D conversion is then performed for ANn channels selected by the ADANSA register
Starting from the channel with the smallest number n
Each time A/D conversion of a single channel is completed
The A/D conversion result is stored into the corresponding A/D data register (ADDRy)
When A/D conversion of all the selected channels is completed
An S12ADI0 interrupt request is generated
If the ADIE bit in ADCSR is 1
At the same time, the 12-bit A/D converter starts A/D conversion for self-diagnosis
Then starts A/D conversion on ANn channels selected by the ADANSA register
The ADST bit is not automatically cleared to 0
The above steps are repeated as long as the bit remains 1
When the ADST bit is set to 0 (A/D conversion stop), A/D conversion stops

43. Continuous Scan Mode (cont.)
The 12-bit A/D converter enters a wait state
When the ADST bit is later set to 1 (A/D conversion start)
The A/D conversion for self-diagnosis is started again
Example of operation in continuous scan mode
Basic operation + self-diagnosis

44. Continuous Scan Mode (cont.)
Channels selection and self-diagnosis and sample-and-hold
Sample-and-hold operation is first performed
Then A/D conversion is performed for the self-diagnosis voltage
VREFH0 × 0, VREFH0 × 1/2, or VREFH0 × 1 generated from the reference power supply voltage (VREFH0) supplied to the 12-bit A/D converter
After that, A/D conversion is performed on the analog input of the selected channels
Temperature sensor output A/D conversion select bit (TSS) and internal reference voltage A/D conversion select bit (OCS) in ADEXICR should both be set to 0 (non-selection)
Analog input sampling of all the channels whose channel- dedicated sample-and-hold circuit is to be used is started
When the ADST bit in ADCSR is set to 1 (A/D conversion start) by software, synchronous trigger (MTU or ELC), or asynchronous trigger input
After sample-and-hold operation, A/D conversion for self- diagnosis is started

45. Continuous Scan Mode (cont.)
When A/D conversion for self-diagnosis is completed
The A/D conversion result is stored into the A/D self-diagnosis data register (ADRD)
A/D conversion is then performed for ANn channels selected by the ADANSA register
Starting from the channel with the smallest number n
Each time A/D conversion of a single channel is completed
The A/D conversion result is stored into the corresponding A/D data register (ADDRy)
When A/D conversion of all the selected channels is completed
An S12ADI0 interrupt request is generated
If the ADIE bit in ADCSR is 1
At the same time, analog input sampling is started for all the channels whose channel-dedicated sample-and-hold circuit is to be used
The ADST bit is not automatically cleared to 0
The above steps are repeated as long as the bit remains 1

46. Continuous Scan Mode (cont.)
When the ADST bit is set to 0 (A/D conversion stop)
A/D conversion stops
The 12-bit A/D converter enters a wait state
When the ADST bit is later set to 1 (A/D conversion start)
Analog input sampling is started again for all the channels whose channel-dedicated sample-and-hold circuit is to be used
Example of operation in continuous scan mode
Channel-dedicated sample-and-hold circuit + self-diagnosis

47. Group Scan Mode
A/D conversion is performed once on the analog inputs of all the specified channels in group A and group B
After scanning is started by the MTU or ELC trigger
Scan operation of each group is similar to the scan operation in single scan mode
The group A trigger and group B trigger can be selected using the TRSA[3:0] and TRSB[3:0] bits in ADSTRGR, respectively
The different triggers should be used for group A and group B to prevent simultaneous A/D conversion of group A and group B
Software trigger should not be used
The group A and group B channels to be converted are selected using the ADANSA register and ADANSB register, respectively
Group A and group B cannot use the same channels
The temperature sensor output A/D conversion select bit (TSS) and internal reference voltage A/D conversion select bit (OCS) in ADEXICR should both be set to 0 (non-selection)
When self-diagnosis is selected in group scan mode

48. Group Scan Mode (cont.)
Self-diagnosis is separately executed for group A and group B
An operation in group scan mode using a trigger from the MTU
Scanning of group A is started by the TRG4AN trigger from MTU
When group A scanning is completed
An S12ADI0 interrupt is output if the ADIE bit in ADCSR is 1
Scanning of group B is started by the TRG4BN trigger from MTU
When group B scanning is completed
A GBADI interrupt is output if the GBADIE bit in ADCSR is 1

49. In group scan mode with double trigger mode
Group Scan Mode (cont.)
In group scan mode with double trigger mode
Single scan operation started by the MTU or ELC trigger is performed twice for group A
For group B, single scan operation started by the MTU or ELC trigger is performed once
The group A trigger and group B trigger can be selected using the TRSA[3:0] and TRSB[3:0] bits in ADSTRGR, respectively
The different triggers should be used for group A and group B to prevent simultaneous A/D conversion of group A and group B
Software trigger, synchronous trigger (temperature sensor), or asynchronous trigger (ADTRG0#) should not be used
The group A and group B channels to be A/D-converted are selected using the DBLANS[4:0] bits in ADCSR register and ADANSB register, respectively
The same channels cannot be selected for both groups
In group scan mode, the temperature sensor output A/D conversion select bit (TSS) and internal reference voltage A/D conversion select bit (OCS) in ADEXICR should both be set to 0 (non-selection)

50. Group Scan Mode (cont.) Self-diagnosis cannot be selected
Duplication of A/D conversion data is enabled
By setting the channel numbers to be duplicated to the DBLANS[4:0] bits in ADCSR and setting the DBLE bit in ADCSR to 1
An operation in group scan mode with double trigger mode using a trigger from the MTU
Scanning of group B is started by the TRG0AN trigger from MTU
When group B scanning is completed
A GBADI interrupt is output if the GBADIE bit in ADCSR is 1
The first scanning of group A is started by the first TRG4ABN trigger from the MTU
When the first scanning of group A is completed
The conversion result is stored into ADDRy
An S12ADI0 interrupt request is not generated irrespective of the ADIE bit setting in ADCSR
The second scanning of group A is started by the second TRG4ABN trigger from the MTU

51. Group Scan Mode (cont.)
When the second scanning of group A is completed
The conversion result is stored into ADDBLDR
An S12ADI0 interrupt is output if the ADIE bit is 1

52. Asynchronous Triggers
The A/D conversion can be started by the input of an asynchronous trigger
The A/D conversion start trigger select bits (ADSTRGR.TRSA[3:0]) should be set to 0000b
A high-level signal should be input to the asynchronous trigger
ADTRG0# pin
The ADCSR.TRGE and ADCSR.EXTRG bits should be set to 1

53. When the temperature sensor output is converted
Synchronous Triggers
The A/D conversion can be started by a synchronous trigger of the MTU, TPU, ELC, or temperature sensor
The ADCSR.TRGE bit should be set to 1
The ADCSR.EXTRG bit should be cleared to 0
The relevant source should be selected by ADSTRGR.TRSA[3:0] and TRSB[3:0] bits
When the temperature sensor output is converted
A trigger from the temperature sensor should be used to start the A/D conversion
A trigger from the temperature sensor cannot be used when an analog input channel or the internal reference voltage is converted

54. Interrupt Sources
The 12-bit A/D converter can send scan end interrupt requests S12ADI0 and GBADI to the CPU
Setting the ADIE bit in ADCSR to 1 and 0 enables and disables an S12ADI0 interrupt, respectively
Setting the GBADIE bit in ADCSR to 1 and 0 enables and disables a GBADI interrupt, respectively
The DTC or DMAC can be started up when an S12ADI0 or a GBADI interrupt is generated
Using an interrupt to allow the DTC or DMAC to read the converted data enables continuous conversion without burden on software
The ELC connects the S12ADI0 interrupt request signal to the predetermined module as the event signal
i.e., event linkage
The GBADI interrupt request cannot be used as the event signal
The event signal can be output
Irrespective of the setting of the corresponding interrupt request enable bit

55. Interrupt Sources (cont.)
The 12-bit A/D converter outputs the A/D conversion end event
The 12-bit A/D converter can be started by the predetermined event by setting ELSRn of the ELC
When an event occurs during A/D conversion, it is invalid

56. Registers
A/D Control Register (ADCSR)

57. Registers (cont.)
A/D Control Extended Register (ADCER)

58. Registers (cont.)
A/D Channel Select Register A (ADANSA)
A/D Channel Select Register B (ADANSB)

59. Registers (cont.)
A/D Sample and Hold Circuit Control Register (ADSHCR)

60. Registers (cont.)
A/D Conversion Extended Input Control Register (ADEXICR)

61. A/D Data Registers y (ADDRy) (y = 0 to 15)
Registers (cont.)
A/D Data Registers y (ADDRy) (y = 0 to 15)
ADCER.ADRFMT = 0 (Setting for right-alignment)
ADCER.ADRFMT = 1 (Setting for left-alignment)
When A/D-converted value addition mode is selected

62. A/D Data Duplication Register (ADDBLDR)
Registers (cont.)
A/D Data Duplication Register (ADDBLDR)
ADDBLDR ADCER.ADRFMT = 0 (Setting for right-alignment)
ADCER.ADRFMT = 1 (Setting for left-alignment)
When A/D-converted value addition mode is selected

63. A/D Self-Diagnosis Data Register (ADRD)
Registers (cont.)
A/D Self-Diagnosis Data Register (ADRD)
ADCER.ADRFMT = 0 (Setting for right-alignment)
ADCER.ADRFMT = 1 (Setting for left-alignment)

64. A/D Temperature Sensor Data Register (ADTSDR)
Registers (cont.)
A/D Temperature Sensor Data Register (ADTSDR)
ADCER.ADRFMT = 0 (Setting for right-alignment)
ADCER.ADRFMT = 1 (Setting for left-alignment)

65. A/D Internal Reference Voltage Data Register (ADOCDR)
Registers (cont.)
A/D Internal Reference Voltage Data Register (ADOCDR)
ADCER.ADRFMT = 0 (Setting for right-alignment)
ADCER.ADRFMT = 1 (Setting for left-alignment)

66. Registers (cont.)
A/D Start Trigger Select Register (ADSTRGR)

67. D/A converter
It converts a digital value stated by programmer to corresponding analog voltage on a microcontroller pin
It may be needed for controlling other devices like motor
RX210 has a 10-bit D/A converter with 2 channels
Analog value = (D/A data register value / 1024) * Vref

68. D/A converter registers
Some of the important registers are:
D/A Data Register (DADRm) (m = 0, 1)
16-bit registers
Holds the digital value to be converted to analog voltage

69. The specifications of the D/A converter
Resolution: 10 bits
Output channels: Two channels
Low power consumption function:
Module stop state can be set for each unit
Event link function (input)
D/A0 conversion can be started when an event signal is input
Pin Configuration of D/A Converter

70. Block Diagram

71. The D/A converter includes D/A conversion circuits for two channels
Operation
The D/A converter includes D/A conversion circuits for two channels
Each of which can operate independently
D/A converter is enabled and the conversion result is output
When the DAOEi bit (i = 0, 1) in DACR is set to 1
An operation example of D/A conversion on channel 0
Write the data for conversion to DADR0
Set the DAOE0 bit in DACR to 1 to start D/A conversion
The conversion result is output from the analog output pin DA0 after the conversion time tDCONV has elapsed
The conversion result continues to be output until DADR0 is written to again
Or the DAOE0 bit is cleared to 0
If DADR0 is written to again, the conversion is immediately started
The conversion result is output after the conversion time tDCONV has elapsed

72. Operation (cont.)
If the DAOE0 bit is cleared to 0, analog output is disabled

73. Registers
D/A Data Register m (DADRm) (m = 0, 1)
DADRm Format Select Register (DADPR)

74. Registers (cont.)
D/A Control Register (DACR)