ICM7217 is a four digit, presettable up/down counter with an onboard presettable register continuously compared to the counter. The ICM7217 is intended for use in hard-wired applications where thumbwheel switches are used for loading data, and simple SPDT switches are used for chip control.
Digital Timers, Counters and Clocks has some of my designs using chips like this.
This circuit provides multiplexed 7 segment LED display outputs, with common anode or common cathode configurations available. Digit and segment drivers are provided to directly drive displays of up to 0.8 inch character height (common anode) at a 25% duty cycle. The frequency of the onboard multiplex oscillator may be controlled with a single capacitor, or the oscillator may be allowed to free run. Leading zeros can be blanked. The data appearing at the 7 segment and BCD outputs is latched; the content of the counter is transferred into the latches under external control by means of the Store pin.
See an Application of 7217 as a Preset Counter which is used in Process Control
Features of Chip
- Four Decade, Presettable Up-Down Counter with Parallel Zero Detect
- Settable Register with Contents Continuously Compared to Counter
- Directly Drives Multiplexed 7 Segment Common Anode or Common Cathode LED Displays
- On-Board Multiplex Scan Oscillator
- Schmitt Trigger On Count Input
- TTL Compatible BCD I/O Port, Carry/Borrow, Equal, and Zero Outputs
- Display Blank Control for Lower Power Operation; Quiescent Power Dissipation <5mW
- All Terminals Fully Protected Against Static Discharge
- Single 5V Supply Operation
This is another Intersil Masterpiece in days when using uP was complex and uC was not available.A 8085 could be used but with many supporting chips and it consumed power. This was a CMOS innovation low on power and just one ASIC had the fexibility for many digital operations.A ThumbWheel and Display Interface completed a Gadget.