SIOA7 Stand Alone UART - Serial Input/Output IC

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ABCircuits www.abcircuits.com POB 123 New Hill NC 27562 (919) 290-7104
SIOA7 IC
Stand Alone UART IC
7 bits of input and 7 bits of output
Expandable and Addressable
General Description
The SIOA7 IC is a stand alone UART designed to provide 7 bits of input and output data.
(Expandable to 112 bits.) The SIOA7 may connect to RS-232, USB, RS-485, Ethernet or directly
to your UART. Outputs can be used to drive relays, logic, optocouplers or a transistors. Inputs
can be from switches, relay contacts, logic, optocouplers or a transistor switched to ground. The
SIOA7 has internal pull resistors on most inputs to minimize additional parts. After receiving an
address byte matching the ADR0-3 pins is received on the SIN- pin, the next bye received on the
SIN- pin is placed on the OA0-6 pins and the data on the IA0-6 pins are transmitted SOUT- pin.
A positive pulse is generated on the RXP pin every time a byte is placed on the OA0-6 pins.
More than one SIOA7 chip may be connected together to achieve up to 112 bits of input and
output. The serial format to the SIOA7 is standard asynchronous format, using 8 bits, 1 stop and
no parity at 9600 BPS. Other formats and encoding are available, contact the factory. A .1 uF
bypass capacitor is suggested across the VDD and VSS pins. The part uses the standard 28 pin
.3 inch width SOIC package.
Features
• Asynchronous serial control for 7
•
•
•
•
•
•
•
•
•
•
•
•
•
bits of input and 7 bits of output,
expandable to 112 bits.
Can connect with RS-232, RS -485,
USB or Ethernet or UART.
Inputs can be switches, relay
contacts, optocouplers, and logic.
On chip input pull up resistors on
most inputs.
Outputs can be used to drive relays,
transistors, optocouplers, and logic.
Applications
• Input Output Expansion
• Remote control
• Process control
• Building Automation
• Off site monitoring
• Security systems
• Internet of things
• Machine control
No external parts required.
Low power consumption 5 mA
typical.
Supply voltage 2.4 to 5.25 volts.
All timing internally generated.
TTL and CMOS compatible outputs.
Part is in full production.
SOIC and DIP 28 Pin Package.
ROHS Compliant
Low EMI
Part Number 74C922-SO
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Example Circuits
7 BITS INPUT/OUTPUT ETHERNET
INPUT A2
INPUT A4
INPUT A6
OUTPUT A0
OUTPUT A2
OUTPUT A4
OUTPUT A6
+3.3
INPUT A5
INPUT A3
INPUT A1
+3.3
LANTRONIX
XPORT
28
27
26
25
24
23
22
21
20
19
18
17
16
15
1
2
3
4
5
6
7
8
GND
+3.3
-POR
OUT
IN
CP1
CP2
CP3
ETHERNET
OUTPUT A5
OUTPUT A3
OUTPUT A1
SEE EXPANSION CIRCUIT
SIOA7
1
RXP
VDD
2
TXE
3 ADR3
ADR2
4 ADR1
ADR0
5 SOUTSIN6 NC
OA6
7 OA5
OA4
8 OA3
OA1
OA2
9
NC
OA0
10
NC
11 NC
IA6
12 IA5
IA4
13 IA3
IA2
14 IA1
VSS
IA0
INPUT A0
VCC
7 BITS INPUT/OUTPUT RS-232
1
.1
3
4
.1
INPUT A5
INPUT A3
INPUT A1
5
11
10
12
9
VCC
V+
2
.1
C1C2+
V-
6
T1in
T1out
T2in
T2out
R1out
R1in
R2out
R2in
RS232
DB9S
.1
C2-
GND
VCC
28
27
26
25
24
23
22
21
20
19
18
17
16
15
U2
SEE NOTES
14
7
13
8
1
2
3
4
5
6
7
8
9
8
15
OUTPUT A5
OUTPUT A3
OUTPUT A1
SEE EXPANSION CIRCUIT
SIOA7
1
VDD
2 RXP
ADR3
TXE
3
ADR1
ADR2
4
ADR0
5 SOUTNC
SIN6
OA6
7 OA5
OA3
OA4
8
OA1
OA2
9
OA0
10 NC
NC
NC
11
IA5
IA6
12
IA4
13 IA3
IA1
IA2
14
VSS
IA0
C1+
VCC
16
INPUT A2
INPUT A4
INPUT A6
OUTPUT A0
OUTPUT A2
OUTPUT A4
OUTPUT A6
U2= MAX232 FOR 5V RS232
U2= MAX3232 FOR 3V RS232
INPUT A0
Part Number SIOA7
Copyright © 2014 ABCircuits. Revised September 2014 Page 2 of 10
TXD
RXD
GND
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7 BITS INPUT/OUTPUT RS-485
INPUT A2
INPUT A4
INPUT A6
OUTPUT A0
OUTPUT A2
OUTPUT A4
OUTPUT A6
VCC
VCC
4.7K
OUTPUT A5
OUTPUT A3
OUTPUT A1
INPUT A5
INPUT A3
INPUT A1
SEE EXPANSION CIRCUIT VCC
SIOA7
1
28
RXP
VDD
2
27
ADR3
TXE
3
26
ADR2 25
4 ADR1
ADR0 24
5 SOUTNC
SIN6
23
OA6 22
7 OA5
OA3
OA4 21
8
OA2 20
9 OA1
NC
OA0
10
19
NC 18
11 NC
IA5
IA6 17
12
IA4 16
13 IA3
IA1
IA2
14
15
VSS
IA0
U2
1
2
3
4
RO
VCC
-RE
-DO/-RI
DE
DO / RI
DI
GND
8
7
RS485
6
5
U2 75176 FOR 5V
U2 MAX3485 FOR 3.3V
INPUT A0
7 BITS INPUT/OUTPUT USB
INPUT A2
INPUT A4
INPUT A6
OUTPUT A0
OUTPUT A2
OUTPUT A4
OUTPUT A6
INPUT A5
INPUT A3
INPUT A1
4.7
.1
USB
1
2
3
4
5
16
15
CASE
REFER TO FT232 DATASHEET
FOR MORE DETAILS
19
27
28
8
24
USBM
USBP
-RST
OSCI
OSCO
NC
NC
GND
GND
GND
AGND
TEST
SEE EXPANSION CIRCUIT VCC
SIOA7
1
28
VDD 27
2 RXP
TXE 26
3 ADR3
ADR1
ADR2
4
25
SOUTADR0
5
24
NC
SIN6
23
OA6 22
7 OA5
OA4 21
8 OA3
OA2 20
9 OA1
OA0 19
10 NC
NC 18
11 NC
IA5
IA6 17
12
IA4 16
13 IA3
IA1
IA2 15
14
VSS
IA0
VCC
VCCIO
3VOUT
20
4
17
FT232-SSOP
TXD
RXD
DTR
-CTS
RTS
RI
DSR
DCD
CBUS0
CBUS1
CBUS2
CBUS3
CBUS4
1
5
2
11
3
6
9
10
23
22
13
14
12
7
18
21
25
26
OUTPUT A5
OUTPUT A3
OUTPUT A1
VCC
.01 BEAD . 1
INPUT A0
Part Number SIOA7
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ADDRESS 15
SIOA7
1
2
3
4
5
6
7
8
9
10
11
12
13
14
RXP
ADR3
ADR1
SOUTNC
OA5
OA3
OA1
NC
NC
IA5
IA3
IA1
VSS
VDD
TXE
ADR2
ADR0
SINOA6
OA4
OA2
OA0
NC
IA6
IA4
IA2
IA0
EXPANSION EXAMPLE
28
27
26
25
24
23
22
21
20
19
18
17
16
15
RS-232, RS-485,
USB, ETHERNET,
OR UART
ADDRESS 1
SIOA7
1
2
3
4
5
6
7
8
9
10
11
12
13
14
RXP
ADR3
ADR1
SOUTNC
OA5
OA3
OA1
NC
NC
IA5
IA3
IA1
VSS
VDD
TXE
ADR2
ADR0
SINOA6
OA4
OA2
OA0
NC
IA6
IA4
IA2
IA0
28
27
26
25
24
23
22
21
20
19
18
17
16
15
ADDRESS 0
SIOA7
1
2
3
4
5
6
7
8
9
10
11
12
13
14
RXP
ADR3
ADR1
SOUTNC
OA5
OA3
OA1
NC
NC
IA5
IA3
IA1
VSS
VDD
TXE
ADR2
ADR0
SINOA6
OA4
OA2
OA0
NC
IA6
IA4
IA2
IA0
28
27
26
25
24
23
22
21
20
19
18
17
16
15
Part Number SIOA7
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VCC
EXPANSION ON RS-485 BUS
VCC
4.7K
ADDRESS 0
SIOA7
1
2
3
4
5
6
7
8
9
10
11
12
13
14
RXP
ADR3
ADR1
SOUTNC
OA5
OA3
OA1
NC
NC
IA5
IA3
IA1
VSS
VDD
TXE
ADR2
ADR0
SINOA6
OA4
OA2
OA0
NC
IA6
IA4
IA2
IA0
VCC
U2
1
28
27
26
25
24
23
22
21
20
19
18
17
16
15
2
3
4
RO
VCC
-RE
-DO/-RI
DE
DO / RI
DI
GND
8
7
6
RS485
5
U2 75176 FOR 5V
U2 MAX3485 FOR 3.3V
VCC
VCC
4.7K
ADDRESS 1
SIOA7
1
2
3
4
5
6
7
8
9
10
11
12
13
14
RXP
ADR3
ADR1
SOUTNC
OA5
OA3
OA1
NC
NC
IA5
IA3
IA1
VSS
VDD
TXE
ADR2
ADR0
SINOA6
OA4
OA2
OA0
NC
IA6
IA4
IA2
IA0
VCC
U2
1
28
27
26
25
24
23
22
21
20
19
18
17
16
15
2
3
4
RO
VCC
-RE
-DO/-RI
DE
DO / RI
DI
GND
8
7
6
5
U2 75176 FOR 5V
U2 MAX3485 FOR 3.3V
Connection Diagram
SIOA7
1
2
3
4
5
6
7
8
9
10
11
12
13
14
RXP
ADR3
ADR1
SOUTNC
OA5
OA3
OA1
NC
NC
IA5
IA3
IA1
VSS
VDD
TXE
ADR2
ADR0
SINOA6
OA4
OA2
OA0
NC
IA6
IA4
IA2
IA0
28
27
26
25
24
23
22
21
20
19
18
17
16
15
Part Number SIOA7
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Pin Description
Pin #
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Description
RXP
ADR3
ADR1
SOUTNC
OA5
OA3
OA1
NC
NC
IA5
IA3
IA1
VSS
Pin #
28
27
26
25
24
23
22
21
20
19
18
17
16
15
Description
VDD
TXE
ADR2
ADR0
SINOA6
OA4
OA2
OA0
NC
IA6
IA4
IA2
IA0
OA0-6
These output bits are set when a byte is received on the SIN- pin after a matching address byte is
received on the SIN- pin. Output drivers may be required for high power loads. The RXP pin
generates a positive pulse after these bits are set.
SINThis is the serial input pin. It may be tied directly to the UART transmitter output of your UART or
microprocessor; to a RS -232 receiver such as the MAX232; an Ethernet interface such as the
Lantronix Xport; or a USB IC such as the FT232. This pin is high in the idle state, the input
format is 8 bits, 1 stop, no parity at 9600 BPS. Other formats and baud rates are available,
please contact the factory for information. After a matching address bye is received on this pin
the next byte received on this pin will be transferred to the OA0-6 pins if bit 8 is zero, then a
positive pulse is generated on the RXP output. This pin does not have an internal pull up resistor.
If you are using a receiver with tristate outputs, such as the 75176 for RS -485, a pull up resistor
will be required. It is recommended your software periodically send the address byte and second
byte containing the OA0-6 byte even if they have not changed to recover from communications
errors or power failures.
To be a valid address byte, bit 8 must be 1, bits 7,6, and 5 must be 0; and bits 4 to 1 must match
the address pins. Bit 8 must be 0 to be transferred to the OA0-6 pins.
You can drive this input with any hexadecimal terminal program like REALTERM for testing and
development.
SOUTThis is the serial output pin. It is open drain with an internal pull up resistor, so more than one
SOUT- pin may be directly tied together. It may be tied directly to the UART receiver input of
your UART or microprocessor; to a RS -232 driver such as the MAX232; an Ethernet interface
such as the Lantronix Xport, or a USB IC such as the FT232. After a matching address byte and
the byte for the OA0-6 pins this pin sends the data on the IA0-6 pins, adding start and stop bits.
This pin is high in the idle state, the output format is 8 bits, 1 stop, no parity at 9600 BPS. Other
output formats and baud rates are available, please contact the factory for information.
Part Number SIOA7
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You can monitor this output with any hexadecimal terminal program like REALTERM. Hyperterm
does not display in hexadecimal.
IA0-6
These are the input bits that will be transmitted on the SOUT- pin. These inputs have internal pull
up resistors.
ADR0-3
These pins determine the device address. A byte received on the SIN- pin with bit 8 set to one is
and bits 7,6, and 5 are zero it is an address byte. The lower 4 bits must mach the ADR0-3 pins,
or the device returns to wait for address mode. If the address matches, the next byte received is
placed on the OA0-6 pins, a positive pulse is generated on the RXP pin. Then the inputs of the
IA0-6 pins are transmitted on the SOUT- pin, with bit 8 of the transmitted byte set to zero. Up to
16 devices can be used on the same communications channel, either on the same board, or on
separate boards if a multi-drop interface such as RS-485 is used.
Device Address
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Address Byte (hex)
80
81
82
83
84
85
86
87
88
89
8A
8B
8C
8D
8E
8F
ADR3
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Open
Open
Open
Open
Open
Open
Open
Open
ADR2
Ground
Ground
Ground
Ground
Open
Open
Open
Open
Ground
Ground
Ground
Ground
Open
Open
Open
Open
ADR1A
Ground
Ground
Open
Open
Ground
Ground
Open
Open
Ground
Ground
Open
Open
Ground
Ground
Open
Open
ADR0
Ground
Open
Ground
Open
Ground
Open
Ground
Open
Ground
Open
Ground
Open
Ground
Open
Ground
Open
RXP
This pin outputs a positive pulse after a byte is placed on the OA0-6 pins.
TXE
This pin goes high while the byte on the SOUT- pin is being transmitted. This pin goes low again
after the stop bit has been sent. This pin is designed to drive the RE - (receiver enable) and DE
(driver enable) pins on a RS -485 driver IC. Please note, in RS-485 applications, an external pull
up resistor is required on the SIN- pin.
VSS
Connect to system ground.
VDD
Connect to supply voltage of 2.4 to 5 volts. A .1 uF decoupling capacitor to ground is
recommended.
NOTES:
Make no connection to the NC pins. Pins 9 and 19 must be left unconnected.
Part Number SIOA7
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Serial Input Stream
DATA STREAM
ADDRESS BYTE
START ADR0 ADR1 ADR2 ADR3
0
OUTPUT OA BITS
0
0
1
STOP
START
OA0
OA1
OA2
OA3
OA4
OA5
OA6
0
STOP
BIT CELLS
When a byte is received on the SIN- pin, bit 8 is checked. If bit 8 is 1 and bits 7,6, and 5 are zero
the lower 4 bits are compared to the ADR0-3 pins. If that also matches, the next byte received on
the SIN- pin is placed on the OA0-6 pins if bit 8 of that byte is zero. The SIOA7 automatically
removes start and stop bits from the data stream. The data is format is 9600 BPS, 8 bits, 1 stop,
no parity. After the data is placed on the OA0-6 pins, the RXP pin generates a positive pulse.
The bits on IA0-6 are then transmitted, with the eighth bit being sent as a zero.
Serial Output Stream
INPUT IA BITS
START
IA0
IA1
IA2
IA3
IA4
IA5
IA6
0
STOP
BIT CELLS
After a valid matching address byte, and the next byte for the OA0-6 pins are received, the bits
from IA0-6 are transmitted on the SOUT- pin. Bit 8 is transmitted as a zero. The SIOA7
automatically adds start and stop bits to the data stream. The data is transmitted at 9600 BPS, 8
bits, 1 stop, no parity.
Absolute Maximum Ratings
Symbol
Description
Tstg
Ta
V dd
V io
Imio
ESD
Storage Temperature
Operating Temperature
LU
Latch up current
V dd - V ss Voltage
Input Voltage
Maximum current into any pin
Electrostatic Discharge Voltage
Min
-55
-40
-0.5
Typical
Max
Units
25
+100
+85
+6.0
ºC
ºC
V
V
mA
V
Vss - 0.5
-25
2000
V dd +0.5
+50
200
Notes
Human Body Model
ESD
mA
DC Electrical Characteristics
Symbol
Description
V dd
Idd
V oh
V ol
V ih
V il
Ioh
Supply Voltage
Supply Current
High Output Level
Low Output Voltage
Input High Level
Input Low Level
High Level Source Current
Min
Typical
Max
Units
5
5.25
8
V
mA
V
V
V
V
mA
2.4
V dd - 1.0
0.75
2.1
0.8
10
Notes
Note 1
Ioh=10 mA
Iol=25 mA
Part Number SIOA7
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Iol
Cio
Iil
Rpu
Low Level Sink Current
Capacitive load
Input leakage
Pull Up Resistors On Inputs
IA0-6
4
3.5
1
5.6
25
10
8
mA
pF
nA
k?
Note 1: Vdd=5VDC, all inputs and outputs open
Theory Of Operation
The SIOA7 IC is a custom programmed microprocessor designed to monitor and control a serial
input and output stream.
When a byte is received on the SIN- pin, bit 8 is checked. If bit 8 is 1 and bits 7,6, and 5 are 0 the
lower 4 bits are compared to the ADR0-3 pins. If that also matches, the next byte received on the
SIN- pin is placed on the OA0-6 pins if the eighth bit is zero. After the data is placed on the OA06 pins, the RXP pin generates a positive pulse. Next the bits from IA0-6 are transmitted on the
SOUT- pin. Bit 8 is transmitted as a zero. The RXE pin is set high before the start bit, and set
back low after the stop bit of the transmitted byte.
The data is standard asynchronous format 8 data bits, 1 stop bit and no parity. Baud rate is 9600
BPS. It is recommended that the address byte and the OA0-6 byte be sent periodically even if
there is no change, to recover from power failure or serial data errors.
Part Number SIOA7
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Physical Dimensions SOIC-28
Physical Dimensions 28 Pin Dip Package (-DIP Suffix)
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Part Number SIOA7
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