Summary of LCD Thermometer TCN77 Using AVR Microcontroller
The TC77 is a digital temperature sensor featuring a SPI/MICROWIRE interface, offering 13-bit resolution and high accuracy across wide temperature ranges. It operates between 2.7V and 5.5V with low power consumption in both active and shutdown modes. The device supports solid-state sensing in SOT-23A or SOIC packages and includes read-only temperature registers alongside a configurable register for power management.
Parts used in the TC77 Digital Temperature Sensor:
- Digital Temperature Sensor (TC77)
- SPI Interface
- MICROWIRE Compatible Interface
- Configuration Register
- Temperature Register
- Manufacturer ID Register
- Chip Select (CS) Signal
- Serial Clock (SCK) Input
- Serial Data (SI/O) Line
- AVR Microcontroller
Description
The TC77 is a digital temperature sensor with a Serial Peripheral Interface. Temperature data is converted from the internal thermal sensing element and made available at anytime as a 13-bit two’s compliment digital word. Communication with the TC77 is accomplished via a SPI and MICROWIRE compatible interface. It has a 12-bit plus sign temperature resolution of 0.0625°C per Least Significant Bit (LSb). The TC77 offers a temperature accuracy of ±1.0°C (max.) over the temperature range of +25°C to +65°C. When operating, the TC77 consumes only 250 ìA (typ.). The TC77’s Configuration register can be used to activate the low power Shutdown mode, which has a current consumption of only 0.1 uA (typ.).
Features:
- Digital Temperature Sensing in 5-Pin SOT-23A and 8-Pin SOIC Packages
- Outputs Temperature as a 13-Bit Digital Word
- SPI and MICROWIRE™ Compatible Interface
- Solid State Temperature Sensing
- ±1°C (max.) accuracy from +25°C to +65°C
- ±2°C (max.) accuracy from -40°C to +85°C
- ±3°C (max.) accuracy from -55°C to +125°C
- 2.7V to 5.5V Operating Range
- Low Power – 250 uA (typ.) Continuous Conversion Mode – 0.1 uA (typ.) Shutdown Mode
Package
The TCN77 is available in a SOIC package.
Serial Bus Interface
The serial interface consists of the Chip Select (CS),Serial Clock (SCK) and Serial Data (SI/O) signals. The TC77 meets the SPI and MICROWIRE bus specifications,with the serial interface designed to be compatible with the Microchip PICmicro® family of microcontrollers.The CS input is used to select the TC77 when multiple devices are connected to the serial clock and data lines. The CS line is also used to synchronize the data, which is written to, or read from, the device when CS is equal to a logic ‘0’ voltage. The SCK input is disabled when CS is a logic ‘1’. The falling edge of the CS line initiates communication, while the rising edge of CS completes the communication. The SCK input is provided by the external microcontroller and is used to synchronize the data on the SI/O line.The Temperature and Manufacturer ID registers are read only while the Configuration register is a read/write register.
Temperature Data Format
A 13-bit two’s complement digital word is used to represent the temperature. The Least Significant Bit (LSb)is equal to 0.0625°C. Note that the last two LSb bits (Bit 0 and 1) are tri-stated and are represented as a logic ‘1’ in the table. Bit 2 is set to logic ‘1’ after the completion of the first temperature conversion following a power up or voltage reset event.
For more details, click:LCD Thermometer TCN77 Using AVR Microcontroller
- How does the TC77 communicate with microcontrollers?
Communication is accomplished via an SPI and MICROWIRE compatible interface using Chip Select, Serial Clock, and Serial Data signals. - What is the temperature resolution of the TC77?
The device provides a 12-bit plus sign temperature resolution of 0.0625°C per Least Significant Bit. - Does the TC77 support low power operation?
Yes, it consumes only 250 uA in continuous conversion mode and drops to 0.1 uA in Shutdown mode when activated via the Configuration register. - What voltage range does the TC77 operate within?
The operating range is specified as 2.7V to 5.5V. - Is the TC77 compatible with Microchip PICmicro family?
Yes, the serial interface is designed to be compatible with the Microchip PICmicro family of microcontrollers. - What format is the temperature data output in?
A 13-bit two's complement digital word represents the temperature data. - Which registers are read-only on the TC77?
The Temperature and Manufacturer ID registers are read-only, while the Configuration register is read/write. - How is communication initiated on the TC77?
The falling edge of the Chip Select line initiates communication, while the rising edge completes it.
