
17. A/D Converter
17.1
Mode Descriptions
The A/D converter has seven different modes.
Table 17.2 lists settings for these modes.
Table 17.2
Mode Settings
17.1.1
One-Shot Mode
In one-shot mode, analog voltage applied to a selected pin is converted to a digital code once.
Table 17.3 lists
specifications of one-shot mode.
Table 17.3
One-Shot Mode Specifications
Mode
AD0CON0 register
AD0CON1 register
AD0CON3 register
MD1 bit
MD0 bit
MD2 bit
MSS bit
DUS bit
One-shot mode
0
Repeat mode
0
1
0
Single sweep mode
1
0
Repeat sweep mode 0
1
0
Repeat sweep mode 1
1
0
Multi-port single sweep mode
10
0
1
Multi-port repeat sweep mode 0
11
0
1
Item
Specification
Function
Analog voltage applied to a selected pin is converted to a digital code once
Analog voltage input pins
Select one pin from AN_0 to AN_7, AN0_0 to AN0_7, AN2_0 to AN2_7, AN15_0
to AN15_7, ANEX0, or ANEX1
The following register settings determine which pin is used:
Bits CH2 to CH0 in the AD0CON0 register
Bits OPA1 and OPA0 in the AD0CON1 register
Bits APS1 and APS0 in the AD0CON2 register
Start Condition
When the TRG bit in the AD0CON0 register is set to 0 (software trigger):
the ADST bit in the AD0CON0 register is set to 1 (A/D conversion starts)
When the TRG bit is set to 1 (external trigger, hardware trigger), one of the
following can be selected:
A falling edge is input to the ADTRG pin after the ADST bit is set to 1
Timer B2 interrupt request of three-phase motor control timer function (after
the ICTB2 register completes counting) is generated after the ADST bit is set
to 1
Stop condition
When the TRG bit is set to 0 (software trigger):
A/D conversion is completed (the ADST bit becomes 0)
When the TRG bit is set to 1 (external trigger, hardware trigger):
Set the ADST bit to 0 (A/D conversion stops)
Interrupt request generation timing A/D conversion is completed
Reading of A/D conversion result
When the DUS bit in the AD0CON3 register is set to 0 (DMAC operating mode
disabled), read the AD0j register (j = 0 to 7) corresponding to a selected pin by
program.
When the DUS bit in the AD0CON3 register is set to 1 (DMAC operating mode
enabled), A/D conversion result is stored into the AD00 register after A/D
conversion is completed. Then, DMAC transfers the data from the AD00
register to a given memory space. (Refer to 12. DMAC for DMAC settings)