In the hardware test of the I2C bus product, when verifying that the timing meets the standard, it is often necessary to measure more than a dozen parameters one by one, which is tedious and time consuming. But if you use this feature, you can get the I2C timing analysis software within 30s. This feature ZDS full range of oscilloscopes can be upgraded for free!
1, I2C bus introduction
The I2C bus is a serial bus introduced by PHLIPS. It is a high-performance serial bus with multi-master systems including bus arbitration and high-low-speed device synchronization. The I2C bus is used to connect the microcontroller to its peripherals.
I2C device selection
Physically, the I2C bus has only two bidirectional signal lines, one for the data line SDA and the other for the clock line SCL.
SCL (serial clock line): The rising edge inputs data into each EEPROM device; the falling edge drives the EEPROM device output data.
SDA (Serial Data Line): A bidirectional data line that is an OD gate and has a "wire-and-pair" relationship with any other number of OD and OC gates.
Figure 2: Internal structure of the I2C bus
The 2C bus is connected to the positive power supply through a pull-up resistor. When the bus is idle, both lines are high. The low level of any device connected to the bus will cause the bus signal to go low, ie the SDA and SCL of each device are in line AND.
I2C has three rates, as follows:
Normal mode (100kHz);
Fast mode (400kHz);
High speed mode (3.4MHz).
I2C bus data validity
During data transmission on the I2C bus, the data on the data line SDA must remain stable during the clock signal SCL high. Only when the signal on the clock line SCL is low, the data line SDA is high or low. The level state is allowed to change, as shown in Figure 3.
Figure 3 data validity
2, I2C timing analysis software
The ZDS4000 Plus Series oscilloscope is the industry's first oscilloscope with standard I2C timing analysis software. The analysis software is suitable for hardware testing of all I2C bus products, especially for hardware testing of batch products. The traditional test method requires manual positioning of each parameter and separate card cursor measurement. The average time to test a group of data is about 30~60 minutes, which is not only inefficient, but also easy to introduce reading errors or even errors.
Using I2C timing analysis software, it can complete the DC characteristics and AC characteristic analysis of the bus signal in a very short time, and compare it with the nominal parameters of the device manual, directly output the test result (Pass/Fail), and support the report export. Eliminate the trouble of manually entering data, greatly improving the efficiency of testing. The specific test interface is shown in Figure 4 below.
Figure 4 I2C timing analysis interface
Handheld Megaphone,Portable Megaphone,Hand Held Loud Speaker,Portable Megaphone With Microphone
Shangqiu Huayitong electronic technology co., Ltd. , https://www.huayitongmegaphones.com