HT46R71D-1 Holtek Semiconductor, HT46R71D-1 Datasheet - Page 23

• Manufacturer Part Number: HT46R71D-1
• Description: Dual Slope A/D Type MCU
• Manufacturer: Holtek Semiconductor

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The Integrator integrates the output voltage increase or
decrease and is controlled by the Switch Circuit - refer
to the block diagram. The integration and de-integration
curves are illustrated by the following.
The comparator will switch the state from high to low
when VC, which is the DSCC pin voltage,drops to less
than 1/6 VDSO.
In general applications, the application program will
switch the ADC to the charging mode for a fixed time
called Ti, which is the integrating time. It will then switch
to the dis-charging mode and wait for V
Rev. 1.00
Bit No.
1~2
4~5
0
3
6
7
ADDISCH0~
ADDISCH1
ADPWREN
ADINTM0~
ADINTM1
ADCCKEN
ADCMPO
ADRR0
Label
Dual slope block (including input OP) power on/off switching.
0: disable Power
1: Power source comes from the regulator.
Defines the ADC discharge/charge. (ADDISCH1:0)
00: reserved
01: charging. (Integrator input connect to buffer output)
10: discharging. (Integrator input connect to VDSO)
11: reserved
Dual Slope ADC - last stage comparator output.
Read only bit, write data instructions will be ignored.
During the discharging state, when the integrator output is less than the reference voltage,
the ADCMPO will change from high to low.
ADC integrator interrupt mode definition. These two bit define the ADCMPO data interrupt
trigger mode: (ADINTM1:0)=
00: no interrupt
01: rising edge
10: falling edge
11: both edge
ADC OP chopper clock source on/off switching.
0: disable
1: enable (clock value is defined by ADCD register)
ADC resisters selection
0: (V
1: (V
INT
INT
, V
, V
CMP
CMP
c
)= (4/6 VOREG, 1/6 VOREG)
)= (4.4/6 VOREG, 1/6 VOREG)
to drop to less
ADCR (18H) Register
23
than 1/6VDSO. At this point the comparator will change
state and store the time taken, Tc, which is the de-inte-
grating time. The following formula 1 can then be used
to calculate the input voltage V
formula 1: V
In user applications, it is required to choose the correct
value of R
the V
1/6VDSO. Vfull cannot be greater than 5/6VDSO and
Vzero cannot be less than 1/6VDSO
Function
C
value to operate between 5/6VDSO and
DS
(Based on ADRR0=0)
A
and C
= (1/3) VDSO (2 Tc/Ti).
DS
to determine the Ti value, to allow
A
.
HT46R71D-1
May 14, 2007