TM1637 4-digit display: specs and pinout
A 4-digit, 7-segment LED display module driven by the TM1637 LED driver and key-scan chip over a two-wire serial interface. The values below describe the TM1637 chip; the module board itself is not covered by an official document.
Specs
| Spec | Value | Source |
|---|---|---|
| TM1637 supply (VDD), normal range | 5 V typical; electrical characteristics are specified for VDD = 4.5 to 5.5 V | source Electrical parameter 2 and 3 (p.9) |
| TM1637 absolute maximum VDD | -0.5 to +7.0 V | source Electrical parameter 1, Limit parameter (p.9) |
| TM1637 input high / low level | VIH 0.7 x VDD min; VIL 0.3 x VDD max | source Electrical parameter 2 (p.9) |
| TM1637 display drive | 8 segments x 6 digits, common-anode LEDs | source Function features (p.1) |
| TM1637 brightness | adjustable in 8 duty-cycle steps | source Function features (p.1) |
| TM1637 interface | Two-wire serial (CLK, DIO); not fully I2C because there is no slave address | source Function features (p.1); data command description (p.3) |
| TM1637 maximum clock | 500 kHz | source Switching character (p.9) |
| TM1637 key scan | 8 x 2 bits | source Function features (p.1) |
| TM1637 operating temperature | -40 to +85 C | source Electrical parameter 1 (p.9) |
Power
| Value | Source | |
|---|---|---|
| Supply | Chip: 5 V typical (4.5-5.5 V characterised); module supply not documented | source Electrical parameter 2 and 3 (p.9) |
Chip pins
These are the pins of the chip on the module, from the chip datasheet. The module's own header may label or expose them differently.
Only the four chip signals needed for the serial interface and power are listed, under the chip's own names. The module's header labels and order, the digit LEDs and the colon wiring are not covered by an official document.
| Pin | Function | Voltage | Notes | Source |
|---|---|---|---|---|
| CLK | Clock input (chip pin 18) | VIH 0.7 x VDD | Chip signal; module header order not documented | source Pin information (p.1); Pin functions (p.2) |
| DIO | Serial data input/output (chip pin 17) | VIH 0.7 x VDD | Chip signal; module header order not documented | source Pin information (p.1); Pin functions (p.2) |
| VDD | Logic supply (chip pin 16) | 4.5-5.5 V characterised | Module header label not documented | source Pin information (p.1); Electrical parameter (p.9) |
| GND | Ground (chip pin 1) | 0 V | Module header label not documented | source Pin information (p.1) |
Build with it
Project ideas for the TM1637 4-digit display. Each link opens Soldr with the prompt filled in; Soldr assigns the pins, checks power and shows how to wire every part.
- Digital clock: The Uno gives 5 V logic and supply, matching the chip's 4.5-5.5 V characterisation.
- Temperature display: Both parts run from the Nano 5 V; the DS18B20 uses one data pin and the display two.
- Dial readout: A potentiometer on an analog input is shown as a number; a simple first project with this display.
Common mistakes
- Treating CLK and DIO as I2C: the chip's two-wire interface is not fully I2C protocol because there is no slave address, so use a TM1637 library rather than the Wire library (source: link, data command description p.3)
- Powering and driving it from 3.3 V: the chip's characteristics are given for VDD of 4.5 to 5.5 V, and VIH is 0.7 x VDD (3.5 V at 5 V), above a 3.3 V logic high (source: link, Electrical parameter p.9)
- Exceeding the chip limit: VDD absolute maximum is 7.0 V, so do not feed it from a 9 V or 12 V rail (source: link, Limit parameter p.9)
Not covered by the official source
- Chip facts only: the module is not documented, so digit current limits and logic-level behaviour of the board are unconfirmed.
- The datasheet's normal-working-range row gives VDD only as 5 V typical with no min or max; the 4.5-5.5 V range is from the electrical characteristic tables.
- The listing says 0.36 inch with a clock colon; no official document confirms either.
Sources
- link (Titan Micro TM1637 datasheet V2.4; M5Stack-hosted copy)