Datasheet

RL78/L12 CHAPTER 11 A/D CONVERTER
R01UH0330EJ0200 Rev.2.00 366
Dec 13, 2013
11.7 A/D Converter Setup Flowchart
The A/D converter setup flowchart in each operation mode is described below.
11.7.1 Setting up software trigger mode
Figure 11-23. Setting up Software Trigger Mode
Start of setup
PER0 register setting
ADPC and PMCx register settings
PM register setting
The ADCEN bit of the PER0 register is set (1), and supplying the clock starts.
The ports are set to analog input.
ANI0 and ANI1 pins: Set using the ADPC register
ANI16 to ANI23 pins: Set using the PMCx register
The ports are set to the input mode.
• ADM0 register
FR2 to FR0, LV1, and LV0 bits: These are used to specify the A/D conversion time.
• ADM1 register
ADTMD1 and ADTMD0 bits: These are used to specify the software trigger mode.
ADSCM bit: Sequential conversion mode/one-shot conversion mode
• ADM2 register
ADREFP1, ADREFP0, and ADREFM bits: These are used to select the reference
voltage.
ADRCK bit: This is used to select the range for the A/D conversion result
comparison value generated by the interrupt signal from AREA1,
AREA3, and AREA2.
ADTYP bit: 8-bit/10-bit resolution
• ADUL/ADLL register
These are used to specify the upper limit and lower limit A/D conversion result
comparison values.
• ADS register
ADS4 to ADS0 bits: These are used to select the analog input channels.
ADCE bit setting
The ADCE bit of the ADM0 register is set (1), and the system enters the A/D
conversion standby status.
Reference voltage stabilization
wait time count B
The reference voltage stabilization wait time (1 μ s) is counted by the software.
Start of A/D conversion
End of A/D conversion
The A/D conversion operations are performed.
The A/D conversion end interrupt (INTAD) is generated.
Note
Storage of conversion results in
the ADCR and ADCRH registers
The conversion results are stored in the ADCR and ADCRH registers.
ADCS bit setting
After counting up to the reference voltage stabilization wait time B ends, the ADCS bit
of the ADM0 register is set (1), and A/D conversion starts.
Reference voltage stabilization
wait time count A
The reference voltage stabilization wait time indicated by stabilization wait time count
A is required when the value of the ADREFP1 and ADREFP0 bits is changed.
If change the ADREFP1 and ADREFP0 = 1, 0: A = 5
μ s
If change the ADREFP1 and ADREFP0 = 0, 0 or 0, 1: No wait
• ADM0 register setting
• ADM1 register setting
• ADM2 register setting
• ADUL/ADLL register setting
• ADS register setting
(The order of the settings is
irrelevant.)
Note Depending on the settings of the ADRCK bit and ADUL/ADLL register, there is a possibility of no interrupt
signal being generated. In this case, the results are not stored in the ADCR, ADCRH registers.
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