Is the memory bus visible at all to allow the addition of (unlimited) I/O expansion?
- posted
4 years ago
Is the memory bus visible at all to allow the addition of (unlimited) I/O expansion?
No.
And it's not a memory bus these days, it would be an AXI master or slave interface, or something like PCIe. The Pi4 has PCIe, but you'd have to desolder the USB chip and tap into the wiring - there's no external PCIe slots. Somebody has hacked it (of course):
Theo
It turns out there is a 'Secondary Memory Interface' (SMI) which can be used to talk to slave devices, eg:
Theo
The OrangePi4 has PCIe pins
-- Mike Easter
No, but USB offers many possibilities. What functions do you require from expanded I/O, and how fast do they have to respond?
David
No, but there are many other interfaces available that might be usable. For example, you could connect one or more I/O expanders to the SPI interface or the I2C interface:
Stephen Early
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