pad&pin

Reference from codeium:

Question 1 :
what is a pad and what is a pin in this context? What is the relation between them?

Answer 1:
In the context of microcontrollers and other embedded hardware, a "pad" and a "pin" refer to aspects of the physical and electrical interface that microcontrollers offer for connectivity to other devices or peripherals.

Pad:

A "pad" is the physical and electrical interface on the integrated circuit (IC) or chip. It's the actual contact area that can be connected to the PCB (printed circuit board).
Pads are designed to support various electrical characteristics and functions, such as providing power, grounding, or transmitting data.
Pads can often be configured for different functions or modes (like GPIO, I2C, SPI, etc.), and can also have configurations for pull-up/pull-down resistors, drive strength, speed, etc.
Pin:

A "pin" typically refers to the external, physical metal lead that comes out of a chip package and is soldered to a PCB. Each pin is electrically connected to a pad on the IC.
Pins serve as a means to interface the microcontroller with the outside world. They can be configured as input or output and can interact with sensors, actuators, other ICs, etc.
The term "pin" is also used in the firmware to refer to the logical representation of these physical pins, which can be controlled or read via the microcontroller's programming.
Relation between Pad and Pin:

The pad is the part of the silicon die that is wired to a specific pin on the IC package. When you configure a pad (through functions like Pad_Config), you're setting up the electrical characteristics of how the internal circuitry of the microcontroller is connected to the outside world through that pin.
The pin is what you physically interact with when you connect wires or components to the microcontroller, and what you logically interact with in your code when you set a pin as high or low, or read its state.
In summary, when you're writing code for a microcontroller and you configure a pin, you're often also configuring the corresponding pad that the pin is connected to. The software functions you use interact with the hardware abstraction layer (HAL) or peripheral libraries, which in turn set the appropriate registers that control the behavior of these pins and pads.

Question 2:
A "pad" is the physical and electrical interface on the integrated circuit (IC) or chip. It's the actual contact area that can be connected to the PCB (printed circuit board). in this context, did it mean pad is inside a ic?

Answer 2:
Yes, in this context, the "pad" is indeed part of the integrated circuit (IC). It is the internal contact area on the surface of the semiconductor chip that is used to connect the silicon die to the external pins of the IC package. These pads are not directly accessible once the IC is packaged, but they are crucial for the internal to external signal and power transmission.

When the IC is manufactured, these pads are connected to the external pins (or leads) of the package through a process such as wire bonding or flip-chip connections. The external pins are what you see and can solder onto a printed circuit board (PCB).

In firmware and hardware descriptions, we often talk about "pin configuration" or "pad configuration" somewhat interchangeably, because configuring a pin for a particular function from the software perspective often involves configuring the internal pad that is electrically connected to that pin.