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ST92R195C - A/D CONVERTER (A/D)
A/D CONVERTER (
Cont’d
)
8.10.4 Register Description
A/D CONTROL LOGIC REGISTER (ADCLR)
R241 - Read/Write
Register Page: 62
Reset value: 0000 0000 (00h)
This 8-bit register manages the A/D logic opera-
tions. Any write operation to it will cause the cur-
rent conversion to be aborted and the logic to be
re-initialized to the starting configuration.
Bit 7:5 =
C[2:0]
:
Channel Address.
These bits are set and cleared by software. They
select channel
i
conversion as follows:
Bit 4 =
FS
:
Fast/Slow
.
This bit is set and cleared by software.
0: Fast mode. Single conversion time: 78 x
INTCLK (5.75μs at INTCLK = 12 MHz)
1: Slow mode. Single conversion time: 138 x
INTCLK (11.5μs at INTCLK = 12 MHz)
Note
: Fast conversion mode is only allowed for in-
ternal speeds which do not exceed 12 MHz.
Bit 3 =
TRG
:
External/Internal Trigger Enable
.
This bit is set and cleared by software.
0: External/Internal Trigger disabled.
1: Either a negative (falling) edge on the EXTRG
pin or an On Chip Event
writes a “1” into the
STR bit, enabling start of conversion.
Note:
Triggering by on chip event is available on
devices with the multifunction timer (MFT) periph-
eral.
Bit 2 =
POW
:
Power Enable
.
This bit is set and cleared by software.
0: Disables all power consuming logic.
1: Enables the A/D logic and analog circuitry.
Bit 1 =
CONT
:
Continuous/Single Mode Select
.
This bit it set and cleared by software.
0: Single mode: after the current conversion ends,
the STR bit is reset by hardware and the con-
verter logic is put in a wait status. To start anoth-
er conversion, the STR bit has to be set by soft-
ware or hardware.
1: Select Continuous Mode, a continuous flow of
A/D conversions on the selected channel, start-
ing when the STR bit is set.
Bit 0 =
STR
:
Start/Stop
.
This bit is set and cleared by software. It is also set
by hardware when the A/D is synchronized with an
external/internal trigger.
0: Stop conversion on channel i. An interrupt is
generated if the STR was previously set and the
AD-INT bit is set.
1: Start conversion on channel i
WARNING:
When
accessing this register, it is rec-
ommended to keep the related A/D interrupt chan-
nel masked or disabled to avoid spurious interrupt
requests.
A/D CHANNEL
i
DATA REGISTER (ADDTR)
R240 - Read/Write
Register Page: 62
Reset value: undefined
The result of the conversion of the selected chan-
nel is stored in the 8-bit ADDTR, which is reloaded
with a new value every time a conversion ends.
7
0
C2
C1
C0
FS
TRG
POW CONT STR
C2
0
0
0
0
1
1
1
1
C1
0
0
1
1
0
0
1
1
C0
0
1
0
1
0
1
0
1
Channel Enabled
Channel 0
Channel 1
Channel 2
Channel 3
Channel 4
Channel 5
Channel 6
Channel 7
7
0
R.7
R.6
R.5
R.4
R.3
R.2
R.1
R.0