
CHAPTER 9 A/D CONVERTER
221
9.4.3 Operation mode and trigger mode
The A/D converter can specify various conversion operations by specifying the operation mode and trigger mode.
The operation mode and trigger mode are set by the ADM0 and ADM1 registers.
The following shows the relation between the operation mode and trigger mode.
Trigger Mode
Operation Mode
Setting Value
Analog Input
ADM0
ADM1
A/D trigger
Select
1 buffer
xx010xxxB
000x0xxxB
ANI0 to ANI7
4 buffers
xx110xxxB
000x0xxxB
Scan
xxx00xxxB
000x0xxxB
Timer trigger
1 trigger
Select
1 buffer
xx010xxxB
00100xxxB
ANI0 to ANI3
4 buffers
xx110xxxB
00100xxxB
Scan
xxx00xxxB
00100xxxB
4 trigger
Select
1 buffer
xx010xxxB
00110xxxB
4 buffers
xx110xxxB
00110xxxB
Scan
xxx00xxxB
00110xxxB
External trigger
Select
1 buffer
xx010xxxB
01000xxxB
4 buffers
xx110xxxB
01000xxxB
Scan
xxx00xxxB
01000xxxB
(1) Trigger mode
There are three types of trigger modes which serve as the start timing of the A/D conversion processing: A/D
trigger mode, timer trigger mode, and external trigger mode. The ANI0 to ANI3 pins are able to specify all
of these modes, but pins ANI4 to ANI7 can only specify the A/D trigger mode. The timer trigger mode consists
of the one-trigger mode and four-trigger mode as the sub-trigger mode. These trigger modes are set by the
ADM1 register.
(a) A/D trigger mode
Generates the conversion timing of the analog input for the ANI0 to ANI7 pins inside the A/D converter
unit. ANI4 to ANI7 pins are always set in this mode.
(b) Timer trigger mode
Specifies the conversion timing of the analog input set for the ANI0 to ANI3 pins using the values set to
the TM11 compare register. This mode can only be specified by pins ANI0 to ANI3.
This register creates the analog input conversion timing by generating the coincidence interrupts of the
four capture/compare registers (CC110 to CC113) connected to the 16-bit TM11.
There are two types of sub-trigger modes: the 1-trigger mode and 4-trigger mode.
1-trigger mode
Mode which uses one coincidence interrupt from timer 11 as the A/D conversion start timing.
4-trigger mode
Mode which uses four coincidence interrupts from timer 11 as the A/D conversion start timing.