My question is based on this question over here.
I just want to clarify what is the purpose of the SPI interrupt signal. Isn't the 4 SPI clock and data lines, & chip select sufficient for the SPI interface?
Also, is the SPI interrupt signal an input or output signal?
I'm using this module. Want to understand whether the host (module) generates the interrupt or receives the interrupt from the slave?
The SPI bus does not contain an interrupt signal. But an SPI target device can route an interrupt request to the SPI bus master as a sideband signal i.e. nothing to do with the SPI bus itself.
The below diagram from your MCP2210 Breakout Module User’s Guide illustrates this. The SPI bus and interrupt request are separate.
If any of your SPI target devices (ICs) have an interrupt request output, which they may not, they can connect it to the MCP2210 GP6 input.
From the MCP2210 datasheet Table 1-1, GP6 can be configured either as an interrupt input or a Chip Select output but not as General-Purpose I/O (GPIO).
The other SE.EE question you reference is about the internal interrupts within an SPI bus master microcontroller (MCU), as the SPI bus master peripheral interrupts the CPU within that MCU. That's different to what you're looking at in this MCP2210 documentation.
Interrupt signals have nothing to do with SPI. This SPI-to-USB adapter also receives an interrupt signal, in case you need it. Many devices that have an SPI bus also generate interrupts, and this adapter can tell the computer there was an interrupt.
If you don't need it, you don't have to use it. In this case you can use the interrupt pin (GP6) as a chip select pin, a general-purpose pin, or nothing, as you want.
