ST52T440F3M6 STMicroelectronics, ST52T440F3M6 Datasheet - Page 50

• Manufacturer Part Number: ST52T440F3M6
• Description: MCU 8-Bit ST52 CISC 8KB EPROM 5V 20-Pin SO
• Manufacturer: STMicroelectronics

Specifications of ST52T440F3M6

• Package: 20SO
• Family Name: ST52
• Maximum Speed: 20 MHz
• Ram Size: 256 Byte
• Program Memory Size: 8 KB
• Operating Supply Voltage: 5 V
• Data Bus Width: 8 Bit
• Program Memory Type: EPROM
• Number Of Programmable I/os: 13
• On-chip Adc: 6-chx12-bit
• Operating Temperature: -40 to 85 °C
• Number Of Timers: 1

ST52T400/T440/E440/T441
7 ANALOG COMPARATOR (ST52X440/441)
7.1 Analog Module Overview
The ST52x440/441 includes an Analog Compara-
tor (AC) among its peripherals.
The Analog Comparator is endowed with analog
and digital elements in order to also allow the user
to make use of it as a single slope Analog to Digi-
tal converter. In particular, ST52x440/441 is
endowed with:
The Analog Comparator peripheral can also be
used as a single slope A/D, supplying a ramp sig-
nal to the pin CS. The selection of the working
mode, as either Analog Comparator or single
slope
REG_CONF3[(0)] bit.
Figure 7.1 Analog Peripheral Block Diagram
50/94
Analog Comparator;
7 channels analog mux (6 external lines, 1
internal voltage reference);
a current source providing 7 programmable
values;
16 bit Timer with a Capture Register and 12 bit
Prescaler;
A/D
can
be
CS
AC0
AC1
AC2
AC3
AC4
AC5
performed
G
Bandgape Ref.=2.5V
NDA
A/D Configuration Registers
7
7
6
6
5
5
via
4
4
3
3
2
2
the
1
1
0
0
+
-
7.2 Comparator Mode
In Analog Comparator mode, REG_CONF3[(0)] is
set to “0”. The AC inputs are available on the
external pins. The reference signal must be con-
nected to the CS pin, the signal to be compared
goes to the analog input AC0.
When the input becomes lower than the refer-
ence, the Analog Comparator output changes to
value “1”. The output can be read on the less sig-
nificative bit of Input Register 1 AC_CHAN0H
(Table 2.1).
7.3 A/D Converter Mode
To use the Analog Comparator for A/D Conver-
sion, REG_CONF3[(0)] bit must be set to “1”.
In A/D Mode either the insertion of an external
capacitor to pin CS or the connection to an exter-
nal signal to generate the reference ramp may be
chosen.
In the first case REG_CONF16[(1)] bit must be set
to “0”. The internal current generator, utilized to
charge the capacitor, provides 7 possible current
values,
REG_CONF3[(7:5)]. The current values are in the
range between 0 to 70 A with step of 10 A.
The capacitor should have a low voltage coeffi-
Vcc
Stop Count
Current Sel.
which
A/D Configuration Registers
7
6
12 bit Presc.
16 bit Timer
Converted
Value
5
CLK
4
can
Timer CLK
3
2
1
Start
be
0
selected
via