Turning Ideas Into Reality ABCircuits www.abcircuits.com POB 123 New Hill NC 27562 (919) 290-7104 SER7 IC Serial to Seven Segment Controller Expandable to 32 digits General Description The SER7 IC is a bridge between serial interfaces and one or two non multiplexed seven segment displays. Data is received in a 32 byte buffer, and translated from ASCII to seven segment codes when a carriage return (Hex 0D) is received. More than one SER7 chip may be connected together to achieve up to 32 digits of display. The SER7 has internal pull resistors on most inputs to minimize additional parts. The SER7 may connect to RS-232, USB, RS-485, Ethernet or directly to your UART. The serial format to the SER7 is standard ASCII 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 and DIP package. Features • Drives one or two seven segment • • • • • • • • • • • • • • displays from serial data. Converts from ASCII to seven segment codes. Few external parts required. Low power consumption 3 mA typical. Supply voltage 2.4 to 5.25 volts. Applications • Data Displays • Vending Machines • Large display control • Numeric Displays • Controls • Ethernet displays • Price signs All timing internally generated. On chip input resistors. Output polarity select. Right or left hand decimal point displays. Right or left display justification. TTL and CMOS compatible. Part is in full production. SOIC and DIP 28 Pin Package. ROHS Compliant. Low EMI. Part Number SER7 Copyright © 2014 ABCircuits. Revised September 2014 Page 1 of 11 Turning Ideas Into Reality ABCircuits www.abcircuits.com POB 123 New Hill NC 27562 (919) 290-7104 Example Circuits – RS-232 display LEFT COMMON ANODE DISPLAY VCC 1 C1+ .1 3 U2 SEE NOTES V+ 2 4 C2+ 5 V- 6 RS232 DB9S .1 C2- 11 T1in 10 T1out T2in 12 R1out R1in R2out R2in SEGLDP SEGLG SEGLF SEGLE SEGLD SEGLC SEGLB SEGLA 1 2 3 4 5 6 7 8 9 8 14 7 13 8 24 26 3 25 4 TXD RXD GND 27 2 1 14 SIN- 5 23 6 22 7 21 8 20 DP G F F E D C E B A VCC A COM B G C D RIGHT COMMON ANODE DISPLAY ADR3 ADR2 ADR1 ADR0 SEGRDP SEGRG SEGRF SEGRE SEGRD SEGRC SEGRB SEGRA POL DP JUST VSS 10 18 11 17 12 16 13 15 DP G F F E D C E B A VCC A COM B G C D 15 GND 9 T2out VDD NC NC .1 C1- .1 SER7 28 19 9 VCC VCC 16 VCC U2= MAX232 FOR 5V RS232 U2= MAX3232 FOR 3V RS232 Example Circuits – RS-485 display VCC VCC 28 19 9 VCC 4.7K VDD NC NC SEGLDP SEGLG SEGLF SEGLE SEGLD SEGLC SEGLB SEGLA U2 1 2 3 4 RO VCC -RE -DO/-RI DE 8 7 DI 24 26 3 25 4 5 GND SIN- 5 23 6 22 7 21 8 20 RS485 6 DO / RI LEFT COMMON ANODE VCC DISPLAY DP A COM G F F B E G D C E C B D A SER7 U2 75176 FOR 5V U2 MAX3485 FOR 3.3V 27 2 1 14 RIGHT COMMON ANODE DISPLAY ADR3 ADR2 ADR1 ADR0 SEGRDP SEGRG SEGRF SEGRE SEGRD SEGRC SEGRB SEGRA POL DP JUST VSS 10 18 11 17 12 16 13 15 DP G F F E D C E B A VCC A COM B G C D Example Circuits – USB display VCC .01 BEAD .1 4.7 VCC .1 USB 16 15 CASE USBP -RST OSCI OSCO NC NC 7 18 21 25 26 REFER TO FT232 DATASHEET FOR MORE DETAILS 19 27 28 8 24 USBM GND GND GND AGND TEST 1 2 3 4 5 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 SER7 28 19 9 24 26 3 25 4 27 2 1 14 VDD NC NC SINADR3 ADR2 ADR1 ADR0 POL DP JUST VSS SEGLDP SEGLG SEGLF SEGLE SEGLD SEGLC SEGLB SEGLA 5 23 6 22 7 21 8 20 LEFT COMMON ANODE VCC DISPLAY DP A COM G F F B E G D C E C B D A RIGHT COMMON ANODE DISPLAY SEGRDP SEGRG SEGRF SEGRE SEGRD SEGRC SEGRB SEGRA 10 18 11 17 12 16 13 15 DP G F F E D C E B A A COM B G C D Part Number SER7 Copyright © 2014 ABCircuits. Revised September 2014 Page 2 of 11 VCC Turning Ideas Into Reality ABCircuits www.abcircuits.com POB 123 New Hill NC 27562 (919) 290-7104 Example Circuits – Ethernet display +3.3 +3.3 GND +3.3 -POR OUT IN CP1 CP2 CP3 ETHERNET 1 2 3 4 5 6 7 8 SER7 28 19 9 LANTRONIX XPORT LEFT COMMON ANODE DISPLAY 24 26 3 25 4 27 2 1 14 VDD NC NC SINADR3 ADR2 ADR1 ADR0 POL DP JUST VSS SEGLDP SEGLG SEGLF SEGLE SEGLD SEGLC SEGLB SEGLA 5 23 6 22 7 21 8 20 DP G F F E D C E B A B G C D RIGHT COMMON ANODE DISPLAY SEGRDP SEGRG SEGRF SEGRE SEGRD SEGRC SEGRB SEGRA 10 18 11 17 12 16 13 15 DP G F F E D C E B A +3.3 A COM +3.3 A COM B G C D Connection Diagram SER7 1 2 3 4 5 6 7 8 9 10 11 12 13 14 JUST DP ADR2 ADR0 SEGLDP SEGLF SEGLD SEGLB NC SEGRDP SEGRF SEGRD SEGRB VSS VDD POL ADR3 ADR1 SINSEGLG SEGLE SEGLC SEGLA NC SEGRG SEGRE SEGRC SEGRA 28 27 26 25 24 23 22 21 20 19 18 17 16 15 Pin Description Pin # 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Description JUST DP ADR2 ADR0 SEGLDP SEGLF SEGLD SEGLB NC SEGRDP SEGRF SEGRD SEGRB VSS Pin # 28 27 26 25 24 23 22 21 20 19 18 17 16 15 Description VDD POL ADR3 ADR1 SINSEGLG SEGLE SEGLC SEGLA NC SEGRG SEGRE SEGRC SEGRA Part Number SER7 Copyright © 2014 ABCircuits. Revised September 2014 Page 3 of 11 Turning Ideas Into Reality ABCircuits www.abcircuits.com POB 123 New Hill NC 27562 (919) 290-7104 POL Polarity input. If this pin is open or high, the “on” segments will have a high level on the SEG outputs of the chip. If this pin is low or grounded “on” segments will output as a low on the SEG pins. This pin is read once at power up and has a built in pull up resistor. DP Right or left hand decimal input. This pin should be open for right hand decimal displays or grounded for left hand decimal displays. This pin is read once at power up and has a built in pull up resistor. JUST Justification input. If this pin is open, the data received will be displayed right justified. If this pin is low or grounded, the data received will be displayed left justified. This pin is read once at power up and has a built in pull up resistor. See also the expansion examples. 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. This pin does not have an internal pull up resistor. It is recommended your software periodically send the data to the displays to recover from communications errors or power failures. You can drive this input with any terminal program like REALTERM or HYPERTERM for testing and development. ADR0-3 These pins determine the device address. 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. See the example circuits for expansion details. Note that the JUST pin controls the placement of device address 0. If the pin is low, (left justify) the Address 0 is on the left end of the chain, and the addresses increase going right. If this pin is open or high, (right justify) the address 0 is on the right side, and addresses increase going left. Part Number SER7 Copyright © 2014 ABCircuits. Revised September 2014 Page 4 of 11 Turning Ideas Into Reality ABCircuits www.abcircuits.com POB 123 New Hill NC 27562 (919) 290-7104 Device Address 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 ADR3 Open Open Open Open Open Open Open Open Ground Ground Ground Ground Ground Ground Ground Ground ADR2 Open Open Open Open Ground Ground Ground Ground Open Open Open Open Ground Ground Ground Ground ADR1A Open Open Ground Ground Open Open Ground Ground Open Open Ground Ground Open Open Ground Ground ADR0 Open Ground Open Ground Open Ground Open Ground Open Ground Open Ground Open Ground Open Ground SEGRA, SEGRB, SEGRC, SEGRD, SEGRE, SEGRF, SEGRG, SEGRDP SEGLA, SEGLB, SEGLC, SEGLD, SEGLE, SEGLF, SEGLG, SEGLDP SEGR is the right hand of the two displays. SEGL is the left hand of the two displays If the POL pin is open or hi, this SEG outputs will be high when a segment is on. If the POL pin is low or grounded, the SEG outputs will be low when a segment is on. These are the eight segment outputs to each individual display SEGDP is the decimal point. An external driver or current limiting resistor is required for each segment. If you are using only a resistor, it must be sized to limit source current to 5 mA maximum per pin or sink current to 9 mA per pin. See also the segment table, and the ASCII to seven segment translation table. 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 SER7 Copyright © 2014 ABCircuits. Revised September 2014 Page 5 of 11 Turning Ideas Into Reality ABCircuits www.abcircuits.com POB 123 New Hill NC 27562 (919) 290-7104 Segment Identification Table Part Number SER7 Copyright © 2014 ABCircuits. Revised September 2014 Page 6 of 11 Turning Ideas Into Reality ABCircuits www.abcircuits.com POB 123 New Hill NC 27562 (919) 290-7104 ASCII To Seven Segment Translation T able Part Number SER7 Copyright © 2014 ABCircuits. Revised September 2014 Page 7 of 11 Turning Ideas Into Reality ABCircuits www.abcircuits.com POB 123 New Hill NC 27562 (919) 290-7104 Expansion Example, Left Justified DISPLAY 1 24 ADR3 ADR2 ADR1 ADR0 SEGL 1 24 SEGR ADR3 ADR2 ADR1 ADR0 IN IN SEGL SER7 26 3 25 4 1 JUST SIN- DISPLAY ADDRESS 15 SER7 26 3 25 4 JUST SIN- DISPLAY ADDRESS 1 IN SER7 IN ADDRESS 0 26 3 25 4 DISPLAY 24 SEGR ADR3 ADR2 ADR1 ADR0 IN DISPLAY IN DISPLAY SEGL JUST SIN- SEGR SIN In left justify mode, address 0 is on the left. A one byte message will be displayed on the left digit of address 0. Expansion Example, Right Justified DISPLAY 1 24 ADR3 ADR2 ADR1 ADR0 SEGL 1 24 SEGR ADR3 ADR2 ADR1 ADR0 IN IN SEGL SER7 26 3 25 4 1 JUST SIN- DISPLAY ADDRESS 0 SER7 26 3 25 4 JUST SIN- DISPLAY ADDRESS 1 IN SER7 IN ADDRESS 15 26 3 25 4 DISPLAY 24 SEGR ADR3 ADR2 ADR1 ADR0 IN DISPLAY IN DISPLAY SEGL JUST SIN- SEGR SIN In right justify mode, address 0 is on the right. A one byte message will be displayed on the right digit of address 0. Using Drivers For Brighter Displays VCC 28 19 9 24 SIN- SEGLDP SEGLG SEGLF SEGLE SEGLD SEGLC SEGLB SEGLA 5 23 6 22 7 21 8 20 1 2 3 4 5 6 7 8 IN1 IN2 IN3 IN4 IN5 IN6 IN7 IN8 OUT1 OUT2 OUT3 OUT4 OUT5 OUT6 OUT7 OUT8 18 17 16 15 14 13 12 11 DP G F F E D C E B A A COM B G C D ULN2804 27 2 1 14 ADR3 ADR2 ADR1 ADR0 POL DP JUST VSS COMMON ANODE RIGHT DISPLAY VCC ULN2804 SEGRDP SEGRG SEGRF SEGRE SEGRD SEGRC SEGRB SEGRA 10 18 11 17 12 16 13 15 1 2 3 4 5 6 7 8 IN1 IN2 IN3 IN4 IN5 IN6 IN7 IN8 GND COM 26 3 25 4 9 10 SIN- VDD NC NC COMMON ANODE LEFT DISPLAY VCC 10 9 SER7 COM GND VCC OUT1 OUT2 OUT3 OUT4 OUT5 OUT6 OUT7 OUT8 18 17 16 15 14 13 12 11 DP G F F E D C E B A A COM B G C D VCC Part Number SER7 Copyright © 2014 ABCircuits. Revised September 2014 Page 8 of 11 Turning Ideas Into Reality ABCircuits www.abcircuits.com POB 123 New Hill NC 27562 (919) 290-7104 Serial Input Stream When a byte is received on the SIN- pin it is placed in the receive buffer. When a carriage return code (Hex 0D) is received on the SIN- pin, the data in the buffer is translated and moved to the displays, Afterward the buffer is cleared. The SER7 uses the ADR0-ADR3 pins to determine which bytes in the buffer to display. Notes: Receive buffer size is 32 bytes. Bit 8 (MSB of the data stream) is ignored. Line feed characters (Hex 0A) are ignored. The decimal point (Hex 2E) activates the decimal point output. The decimal point is not displayed as a separate digit unless required. For instance “1.2” takes two digits to display. “12.” takes two digits to display in right hand decimal mode and three digits to display in left hand decimal mode. “.12” takes two digits to display in left hand decimal mode, and three digits to display in right hand decimal mode. “.1.2.” will take three digits to display. The data is format is 9600 BPS, 8 bits, 1 stop, no parity. Absolute Maximum Ratings Symbol Description Tstg Storage Temperature -55 Ta V dd V io Operating Temperature Imio ESD Maximum current into any pin Electrostatic Discharge Voltage LU Latch up current V dd - V ss Voltage Input Voltage Min Typical Max Units 25 +100 ºC -40 -0.5 +85 +6.0 Vss - 0.5 -25 2000 V dd +0.5 +50 ºC V V mA V 200 Notes Human Body Model ESD mA DC Electrical Characteristics Symbol Description Min V dd Supply Voltage 2.4 Idd V oh V ol Supply Current High Output Level Low Output Voltage V ih V il Ioh Input High Level Input Low Level High Level Source Current Iol Cio Iil Low Level Sink Current Capacitive load Input leakage Rpu Pull Up Resistors On Inputs Typical 3 Max Units 5.25 V 8 0.75 mA V V Note 1 Note 2 Note 3 0.8 10 V V mA Note 2 V dd - 1.0 2.1 3.5 1 4 5.6 25 10 mA pF nA 8 k? Notes Note 3 Note 1: Vdd=5VDC, all inputs and outputs open Note 2 Ioh=10 mA max per pin, 80 mA maximum all pins combined Note 3 Iol=25 mA max per pin 150 mA maximum all pins combined Part Number SER7 Copyright © 2014 ABCircuits. Revised September 2014 Page 9 of 11 Turning Ideas Into Reality ABCircuits www.abcircuits.com POB 123 New Hill NC 27562 (919) 290-7104 Theory Of Operation The SER7 IC is a custom programmed microprocessor designed to monitor a serial input and convert the received data to seven segment format. When a byte is received on the SIN- pin, bit 8 is cleared. The byte is then saved in the buffer. If the byte is a carriage return (0D hex) the IC uses the ADR0-3 inputs to determine which two bytes in the buffer are converted to seven segment format and displayed. 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 display data be sent periodically even if there is no change, to recover from power failure or serial data errors. Part Number SER7 Copyright © 2014 ABCircuits. Revised September 2014 Page 10 of 11 Turning Ideas Into Reality ABCircuits www.abcircuits.com POB 123 New Hill NC 27562 (919) 290-7104 Physical Dimensions SOIC-28 Physical Dimensions 28 Pin Dip Package (-DIP Suffix) Close but not quite? Our products are software based, we can modify existing parts to fit your needs at a minimal cost or create new parts designed to your specifications. Email us and we can make a chip for you! For the latest version of this spec sheet, visit www.abcircuits.com Design Services Available We can quickly turn your idea into a chip, a pc board, or a finished product. Contact us with your needs and specifications. Part Number SER7 Copyright © 2014 ABCircuits. Revised September 2014 Page 11 of 11