Protocol
TM1650 uses 2-wire serial transmission protocol communication.
1: START / END signal (STOP)
Start signal: Holds SCL as "1" level, SDA jumps from "1" to "0", it is considered start signal,
Such as (Figure 3) A segment;
End signal: Holds SCL to "1" level, SDA jumps from "0" to "1", it is regarded as end signal,
Such as (Figure 3) E segment;
2: ACK signal
If the communication is normal, the chip in the serial communication after the falling edge of the first 8 clock, TM1650 take the initiative to SDA low. Until the seizure
Measured to the rising edge of SCL, SDA release for the input state (for the chip), such as (Figure 3) D segment.
3: Writing "1" and writing "0".
Writing "1": Writing "1" to SDA is maintained at "1" level and SCL jumps from "0" to "1" and from "1" to "0"
Such as (Figure 3) B section.
Write "0": Hold SDA to "0" level, SCL from
4: One byte data transfer format
A byte data transmission format shown in Figure 4, the data sent when the first MSB, LSB in the post. The microprocessor's data passes through the two-wire bus
Interface and TM1650 communication, when the input data SCL is high, the SDA signal must remain unchanged; only the SCL
When the clock signal is low, the signal on SDA can be changed. The start condition of the data input is that SDA is changed from high to high when SCL is high
Low; the end condition is that SDA goes from low to high when SCL is high.
5: Read key data timing
Read data, SCL falling edge, the data from the TM1650 SDA pin output.
Characterization
The TM1650 is a dedicated LED driver circuit with a keypad scan interface (LED display). Integrated MCU
Input and output control digital interface, data latches, LED driver, keyboard scanning, brightness adjustment circuit. TM1650 stable performance, quality
The amount of reliable, anti-interference ability, applicable to 24 hours of continuous application of long-term work.
Features
Two display modes: 8 segments × 4 digits and 7 segments × 4 digits
segment drive current greater than 25mA, bit drive current greater than 150mA
Provides 8 levels of brightness control
Keyboard scanning: 7 × 4bit internal integrated transistor driver
high-speed two-wire serial interface
Built-in clock oscillation circuit
Built-in power-on reset circuit
support 2.8V-5.5V power supply voltage
DIP16 and SOP16 package available
Applicable fields:
home appliances such as set-top boxes, air conditioners, DVD / VCD display driver.
Internal structure diagram
Memory Address:
This register stores the data transferred from the external device to the TM1650 through the serial interface in 4-byte units,
A / KI ~ DP / KP and DIG pin connected LED lights corresponding to the distribution of the following chart:
Write LED display data, in accordance with the display address from the high to low, from the data byte high to low operation.
MSB LSB
B7 B6 B5 B4 B3 B2 B1 B0 Function description
× 0 0 0 × ×
Brightness setting
8 levels of brightness
× 0 0 1 × × 1 level of brightness
× 0 1 0 × × 2 levels of brightness
× 0 1 1 × × 3 levels of brightness
× 1 0 0 × × 4 levels of brightness
× 1 0 1 × × 5 levels of brightness
× 1 1 0 × × 6 level brightness
× 1 1 1 × × 7 level brightness
× 0 × ×
The 7/8 segment displays the control bits
8 segment display mode
× 1 × × 7 segment display mode
× × × 0
The display bit is turned on / off
Off display
× × × 1 open display
Note: The bit can be 1, it can be 0, it is recommended to write 0.
ADDRESS: write to the TM1650 memory address
DATA: The data to be displayed is written to the TM1650.
Command1: Data Command: 48H.
Command2: On display, display brightness level.
ADDRESS: memory address.
DATA: Display data.