SPRADO2 November 2024 AM62A3 , AM62A3-Q1 , AM62A7 , AM62A7-Q1
Provide provision for adding parallel pulls to the processor IOs. Parallel pull polarity and the values are dependent on the specific peripheral connectivity recommendations, recommendations for improved processor performance, and relevant interface or standards requirements.
Device-specific SK pull values serve as a starting point and board designers select the appropriate pull values based on the recommendations for the processor and attached device, or specific board design implementation.
When a trace is connected to the processor pads and is not actively driven, a parallel pull is recommended. Pull polarity is design use case dependent. During power-up, processor IO buffers are off and the IOs are in a high impedance state, effectively serving as an antenna that picks up noise. Without any termination, the IOs are high impedance. High impedance means, easy for noise to couple energy on the floating signal trace and develop a potential that can exceed the recommended operating conditions, which creates an electrical over-stress (EOS) on the IOs. Electrostatic discharge (ESD) protection circuits inside the processor are designed to protect the device from handling before being installed on a PCB assembly.