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A/D Converter
The A/D converter has four channels with 6-bit resolution, and can be used for measuring electrical field strength,
measurements of battery and cell voltages and key input using ladder resistance.
1. A/D Converter Control Port and Data Port
Y1
Y2
AD
AD
φL23
SEL0
SEL1
φK20
Y1
Y2
AD0
AD1
LSB
The A/D converter operates using a serial comparison system with 6-bit resolution. The standard voltage for A/D
conversion is the internal power supply (V
input voltage and the data is outputted to the A/D conversion data port. The A/D conversion input uses the multiplex
method; consisting of four channels of external input pins (ADin1 to ADin4 pins) and the half potential of the V
voltage. The desired method can be selected by the AD SEL0 to 2 bits.
The A/D converter carries out A/D conversion each time the STA bit is set to "1", and finishes operation after 6 machine
cycles (240 µs). Completion of the A/D converter operation can be determined by checking the BUSY bit. Once the A/D
conversion is finished, the A/D conversion data is taken into the data memory.
The results of the A/D conversion can be obtained by performing the following calculation:
n − 0.5
(63 > = n > = 1) < = A/D input voltage < = V
×
V
DD
64
V
/2 for A/D input is used for battery detection. The V
EE
voltage, 0.75 V, is selected for A/D input. Through the A/D conversion of this potential, the reference potential, V
be detected. When the V
DD
A/D data becomes higher. When the V
This control is accessed by using the OUT2/IN2 instructions with [CN = 3H, 4H] specified in the operand.
Y4
Y8
AD
STA
SEL2
A/D converter start bit
A/D conversion is implemented each time this is set to "1"
Selection of A/D input pin
SEL2
0
0
0
0
1
φK21
Y4
Y8
Y1
Y2
AD2
AD3
AD4
AD5
A/D conversion data
MSB
), which is divided into 64 parts. The divided voltage is compared to the A/D
DD
(n: A/D conversion data value [decimal scale])
EE
potential is 1.5 V, the A/D conversion data is 20H. As the V
potential is 0.75 V, the A/D conversion data is 3FH.
DD
97
SEL1
SEL0
AD input
0
0
ADin1
0
1
ADin2
1
0
ADin3
1
1
ADin4
V EE /2
*
*
Y4
Y8
BUSY
0
A/D converter operation monitor
0: A/D operation finished
1: A/D converting
n + 0.5
(62 > = n > = 0)
×
DD
64
potential is normally 1.5 V. The half potential of the V
DD
TC9349AFG
pin
EE
pin
EE
, can
DD
potential becomes lower, the
2006-02-24
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