3 operation, Toshiba – Toshiba TMP87CP24AF User Manual
Page 107
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TOSHIBA
TMP87CM24A/P24A
AD Converter Control Register
ADCCR
(OOOE
h
)
7
6
5
4
3
2 1
0
EOCF
ADS
ACK
AINDS
SAIN
______ 1_____ 1_____ 1_____
(Initial value :
0000 0000)
0000
AINO
0001
AIN1
0010
AIN2
0011
AIN3
SAIN
Analog input selection
0100
0101
AIN4
AIN5
0110
AIN6
0111
AIN7
1 ***
Reserved
R/W
AINDS
Analog input control
0 : Enable
1 : Disable
ACK
Conversion time selection
0 : Conversion time = 23
jus
(at fc = 8 MHz)
1 : Conversion time = 92//s
ADS
AD conversion start
0 : -
1 : AD conversion start
EOCF
End of AD conversion flag
0 : Under conversion or Before conversion
1 : End of conversion
Note 1
Note 2
Note3
Note 4
Note 5
*: Don't care
Select analog input when AD converter stops.
The ADS is automatically cleared to "0" after starting conversion.
The EOCF is cleared to "0" when reading the ADCDR.
The EOCF is read-only.
Figure 2-59. AD Converter Control Register and AD Conversion Result Register
2.11.3
Operation
The high side of an analog reference voltage is applied to VAREF pin, and the low side is applied to VASS
pin.
The
reference
voltage
between
VAREF
and
VASS
is
divided
into
the
voltage
corresponding
with
bits
by
radar
resistance.
The
reference
voltage
is
compared
with
an
analog
input
voltage
and
AD
conversion
is performed.
(1) Start of AD conversion
Prior
to
AD
conversion
start,
select
one
pin
among
analog
input
channels
(AIN7
to
AINO)
using
the
SAIN (bit 3 to 0 in ADCCR). Clear AINDS (bit 4 in ADDCCR) to 0 and clear the channel to be used for
analog input using the P5 I/O control register (P5CR).
Note : Pins not used for analog input can be used as an I/O port; to maintain accuracy, do not use
them for output during AD conversion.
Set AD conversion time using the ACK (bit 5 in ADCCR).
To start AD conversion, set AD conversion to "1" using the ADS (bit
6
in ADCCR).
AD
conversion
time
is
from
AD
conversion
start
to
AD
conversion
result
being
set
in
ADCDR.
When
ACK = 0,184/fc [s] (46 machine cycles) is necessary. That is, when fc =
8
MHz, the AD conversion time
is 23 /us.
After AD conversion, the EOCF (bit? in ADCCR) is set to "1" indicating end of conversion.
Setting the ADS to "1" during AD conversion resumes conversion from the beginning.
The analog input voltage is sampled every 4 machine cycles after AD conversion start.
3
-
24-107
2002
-
10-03