Turning Ideas Into Reality ABCircuits www.abcircuits.com POB 123 New Hill NC 27562 (919) 290-7104 CNT7 IC Dual Decade Counter to Seven Segment Controller General Description The CNT7 IC is two decade counters with seven segment outputs for non multiplexed displays. The counter can be used as an up counter or a down counter. More than one CNT7 chip may be connected together to achieve larger displays. The CNT7 has internal pull resistors on inputs to minimize additional parts. The chip also provides clear function, output polarity control and a de-bounce circuit for mechanical switches. 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 packages. Features • Counter drives two seven segment • • • • • • • • • • • • non multiplexed displays. Up or down counter. Mechanical or electronic inputs. Applications • Data Displays • Large display control • Numeric Displays • Controls Few external parts required. Low power consumption 5 mA typical. Supply voltage 3.3 to 5.25 volts. On chip input pull up resistors. Output polarity select. TTL and CMOS compatible. Part is in full production. SOIC and DIP 28 Pin Package. ROHS Compliant Low EMI Part Number CNT7 Copyright © 2014 ABCircuits. Revised September 2014 Page 1 of 7 Turning Ideas Into Reality ABCircuits www.abcircuits.com POB 123 New Hill NC 27562 (919) 290-7104 Example Circuit VCC LEFT COMMON ANODE DISPLAY CNT7 28 19 9 5 26 4 10 3 1 COUNT 25 VDD NC NC NC NC NC CB 23 6 22 7 21 8 20 SW- CLRPOL UP VSS G F E D C B A F B G E C D RIGHT COMMON ANODE DISPLAY CLK DEB CLEAR 2 27 24 14 SEGLG SEGLF SEGLE SEGLD SEGLC SEGLB SEGLA SEGRG SEGRF SEGRE SEGRD SEGRC SEGRB SEGRA 18 11 17 12 16 13 15 G F E D C B A VCC A COM VCC A COM F B G E C D Connection Diagram CNT7 1 2 3 4 5 6 7 8 9 10 11 12 13 14 DEB CLRCLK NC NC SEGLF SEGLD SEGLB NC CB SEGRF SEGRD SEGRB VSS VDD POL NC SWUP SEGLG 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 DEB CLRCLK NC NC SEGLF SEGLD SEGLB NC CB SEGRF SEGRD SEGRB VSS Pin # 28 27 26 25 24 23 22 21 20 19 18 17 16 15 Description VDD POL NC SWUP SEGLG SEGLE SEGLC SEGLA NC SEGRG SEGRE SEGRC SEGRA Part Number CNT7 Copyright © 2014 ABCircuits. Revised September 2014 Page 2 of 7 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. UP This input signal determines count direction, up or down. If this input is open or high, the counter will count up. If this input is grounded or low, the counter will count down. This input is read once at power up and has a built in pull up resistor. CLRThis input clears the counters when low. If the counter is in the up mode, the counter clears to 00. If the counter is in the down mode, the counter clears to 99. CLR is a software derived function, and as such requires 1 mS of minimum input pulse width. This input has a built in pull up resistor. SWSW- and DEB form an optional switch de-bounce circuit. This input would be tied to a switch to ground. An internal pull up resistor is provided. DEB This is the inverted output of the switch de-bounce circuit, which may be tied directly to the CLK input if your design uses a mechanical switch. De-bounce time is about 37 mS, limiting input speed to about 13 clocks per second. The output is push pull. CLK This is the input to the two hardware decade counters. On the positive edge of this input, the counter increments the counters in UP mode; or decrements the counters in down mode. This input does not have a pull up resistor. Maximum clock frequency is 12 MHz. CB This is the counters carry/borrow output. This signal ties to the clock of the next IC in the chain. The output is push pull. SEGRA, SEGRB, SEGRC, SEGRD, SEGRE, SEGRF, SEGRG SEGLA, SEGLB, SEGLC, SEGLD, SEGLE, SEGLF, SEGLG 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 seven segment outputs to each individual display 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. Part Number CNT7 Copyright © 2014 ABCircuits. Revised September 2014 Page 3 of 7 Turning Ideas Into Reality ABCircuits www.abcircuits.com POB 123 New Hill NC 27562 (919) 290-7104 VDD Connect to supply voltage of 3.3 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. Segment Identification Table Seven Segment Translation Table Part Number CNT7 Copyright © 2014 ABCircuits. Revised September 2014 Page 4 of 7 Turning Ideas Into Reality ABCircuits www.abcircuits.com POB 123 New Hill NC 27562 (919) 290-7104 Using Drivers For Brighter Displays VCC 28 19 9 5 26 4 VDD NC NC NC NC NC 10 CB 3 1 COUNT 1 2 3 4 5 6 7 8 2 27 24 14 18 11 17 12 16 13 15 SEGRG SEGRF SEGRE SEGRD SEGRC SEGRB SEGRA 1 2 3 4 5 6 7 8 IN1 IN2 IN3 IN4 IN5 IN6 IN7 IN8 9 10 CLRPOL UP VSS OUT1 OUT2 OUT3 OUT4 OUT5 OUT6 OUT7 OUT8 18 17 16 15 14 13 12 11 RIGHT COMMON ANODE DISPLAY ULN2804 SW- CLEAR IN1 IN2 IN3 IN4 IN5 IN6 IN7 IN8 ULN2804 CLK DEB 25 LEFT COMMON ANODE VCC DISPLAY A COM G F F B E G D C E C B D A 10 9 23 6 22 7 21 8 20 SEGLG SEGLF SEGLE SEGLD SEGLC SEGLB SEGLA COM GND CNT7 GND COM VCC OUT1 OUT2 OUT3 OUT4 OUT5 OUT6 OUT7 OUT8 18 17 16 15 14 13 12 11 G F E D C B A VCC A COM F B G E C D VCC 10 3 CB SEGL CLK SEGR 10 3 CB SEGL CLK SEGR DISPLAY DISPLAY IN CNT7 IN CNT7 DISPLAY IN DISPLAY IN CNT7 DISPLAY IN DISPLAY IN Counter Expansion Example 10 CLK 3 CB SEGL CLK SEGR DISPLAY EXPANSION EXAMPLE 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 200 mA V Notes Human Body Model ESD mA Part Number CNT7 Copyright © 2014 ABCircuits. Revised September 2014 Page 5 of 7 Turning Ideas Into Reality ABCircuits www.abcircuits.com POB 123 New Hill NC 27562 (919) 290-7104 DC Electrical Characteristics Symbol Description V dd Idd V oh Supply Voltage Supply Current High Output Level V ol V ih V il Low Output Voltage Input High Level Input Low Level Ioh Iol Cio High Level Source Current Low Level Sink Current Capacitive load Iil Rpu Input leakage Pull Up Resistors On Inputs Min Typical Max Units 5 5.25 8 V mA V 0.75 Note 3 0.8 V V V mA mA pF Note 2 Note 3 3.5 10 25 10 1 5.6 8 nA k? 3.3 V dd - 1.0 2.1 4 Notes Note 1 Note 2 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 Theory Of Operation The CNT7 IC is a custom programmed microprocessor designed to monitor a hardware counter and display the results. Clear, output polarity and up/down modes are provided as internal software functions. A separate input debouncing function and input/output pins are provided to minimize additional components. Part Number CNT7 Copyright © 2014 ABCircuits. Revised September 2014 Page 6 of 7 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 CNT7 Copyright © 2014 ABCircuits. Revised September 2014 Page 7 of 7