SPRAD21I May 2022 – September 2025 AM620-Q1 , AM623 , AM625 , AM625-Q1 , AM625SIP , AM62A1-Q1 , AM62A3 , AM62A3-Q1 , AM62A7 , AM62A7-Q1 , AM62D-Q1 , AM62P , AM62P-Q1
For I2C interfaces with open-drain output type IO buffers (MCU_I2C0 and WKUP_I2C0), a pullup (4.7kΩ) is recommended irrespective of IO configuration. An external pullup is recommended even when the I2C interface (peripheral) is not used for alternate functions and is expected to be left unconnected.
Refer to the Pin Connectivity Requirements section of the processor-specific data sheet. A pullup (4.7kΩ, adjust after testing) is recommended for the I2C interfaces. I2C interfaces support clock stretching. The clock output frequency (relative to the set frequency) has bus loading dependency. When difference is observed between the set frequency and the measured clock frequency, adjust the pullup (reduce) and measure the clock frequency.
Open-drain output type IO buffer I2C interface when pulled to 3.3V supply, have slew rate requirements specified. An RC (capacitor placed near to the processor I2C interface pins) is recommended to limit the slew rate. For RC implementation, see the AM64x EVM schematic and see the following FAQ:
For more information, see the Connection of Supply Rails to External Pullups section.
In applications where a number of I2C interfaces are required, I2C0, I2C1, I2C2, and I2C3 interfaces can be considered.
I2C0, I2C1, I2C2, and I2C3 interfaces use LVCMOS type IO buffer to emulate an open-drain output type IO and are not fully compliant with the I2C specification, in particular falling edges are fast (< 2ns). Review the exceptions (for I2C0, I2C1, I2C2, and I2C3 interface) in the processor-specific data sheet. A series resistor (47Ω, adjust after testing) is recommended to be placed near to the processor for the interface signals to control the fall time. The series resistor value is recommended to be finalized during testing.
Pullups (4.7kΩ, adjust after testing) are recommended for LVCMOS IOs when the IOs are configured for I2C functionality. The recommendation is to connect the pullups with the shortest stub.
For more information, see the following FAQs:
[FAQ] AM625 / AM623 / AM620-Q1 / AM625-Q1 / AM625SIP Custom board hardware design – I2C interface
[FAQ] AM62A7 / AM62A3 / AM62A1-Q1 and AM62D-Q1 Custom board hardware design – I2C interface
[FAQ] AM62P / AM62P-Q1 Custom board hardware design – I2C interface
The FAQ is generic and can also be used for AM62x (AM625, AM623, AM620-Q1, AM625-Q1, AM625SIP) and AM62Px (AM62P, AM62P-Q1) processor families.
In case the plan is to use TI provided software, connect the recommended processor I2C interface to the PMIC, as I2C0 is the interface used for PMIC control.
The recommendation is to verify the Exceptions sub-section in the Timing and Switching Characteristics, I2C section of the processor-specific data sheet during the custom board design. Take note of the exceptions for the emulated open-drain output type IOs I2C interface. The recommendation is to add a series resistor to control the fall time.