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ZHCSGT3C August 2017 – January 2023 DS90UB954-Q1

PRODUCTION DATA

封装选项

机械数据 (封装 | 引脚)

RGZ|48
- MPQF123F

散热焊盘机械数据 (封装 | 引脚)

RGZ|48
- QFND014T

订购信息

7.5.1.3 Basic I2C Serial Bus Operation

The serial control bus consists of two signals, SCL and SDA. SCL is a Serial Bus Clock Input. SDA is the Serial Bus Data Input / Output signal. Both SCL and SDA signals require an external pullup resistor to 1.8-V or 3.3-V nominal V_I2C. For most applications, TI recommends a 4.7-kΩ pullup resistor to V_I2C. However, the pullup resistor value may be adjusted for capacitive loading and data rate requirements. The signals are either pulled High or driven Low.

The Serial Bus protocol is controlled by START, START-Repeated, and STOP phases. A START occurs when SCL transitions Low while SDA is High. A STOP occurs when SDA transitions High while SCL is also HIGH. See #SNLS4736569.

Figure 7-25 START and STOP Conditions

To communicate with a target device, the host controller (controller) sends the target address and listens for a response from the target. This response is referred to as an acknowledge bit (ACK). If a target on the bus is addressed correctly, it acknowledges (ACKs) the controller by driving the SDA bus low. If the address does not match the target address of the device, it not-acknowledges (NACKs) the controller by letting SDA be pulled High. ACKs also occur on the bus when data is being transmitted. When the controller is writing data, the target ACKs after every data byte is successfully received. When the controller is reading data, the controller ACKs after every data byte is received to let the target know it wants to receive another data byte. When the controller wants to stop reading, it NACKs after the last data byte and creates a stop condition on the bus. All communication on the bus begins with either a Start condition or a Repeated Start condition. All communication on the bus ends with a Stop condition. A READ is shown in #SNLS4735343 and a WRITE is shown in #SNLS4735928.

Figure 7-26 Serial Control Bus — READ

Figure 7-27 Serial Control Bus — WRITE

For more information on I2C interface requirements and throughput considerations, refer to I2C Communication Over FPD-Link III With Bidirectional Control Channel (SNLA131) and I2C Over DS90UB913/4 FPD-Link III With Bidirectional Control Channel (SNLA222).