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I am currently learning to program a NXP LPC1347 for a project which will utilize two SSD1963 controller-based displays. The issue is that the uC only has 51 IO pins whereas the total pins of the display would amount to 26. This leaves too few pins for the peripherals that I need to have on the board (switches, UART, SPI, I2C)

I was initially going to upgrade to a LPC17xx but I figured I could also multiplex the 8-bit data and could save quite a few pins. Perhaps I could even multiplex the 5 control signals as well. Is this a better solution than using a more complex and more expensive part like a LPC17xx or are there pitfalls that I'm not considering?

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  • \$\begingroup\$ Couldn't you just expand your IO by using IO expanders, these can be in either I2C or SPI. \$\endgroup\$ – Dean Oct 24 '12 at 16:09
  • \$\begingroup\$ Datasheet not available .. it seems like a good solution, provided there's a chip select / enable on the controllers. \$\endgroup\$ – pjc50 Oct 24 '12 at 16:31
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In general, a chip like this that has a bus interface can share that interface with other devices of the same or different types, as long as each one has a unique "chip select" signal.

For this particular chip, it looks like you'll also need a separate "TE" status connection from each one as well as a separate "CS#", but all of the rest of the interface signals can be shared.

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  • \$\begingroup\$ I don't know how I missed that it has a CS pin! The TE pin isn't available on the display I'm using so I just need to handle CS and I think I'll be set. \$\endgroup\$ – Saad Oct 24 '12 at 16:41
  • \$\begingroup\$ what are "TE" status connection && "CS Number" ? \$\endgroup\$ – user1610950 Nov 21 '17 at 23:01
  • \$\begingroup\$ @user1610950: Did you look at the datasheet linked above? \$\endgroup\$ – Dave Tweed Nov 22 '17 at 3:47
  • \$\begingroup\$ I didn't see the link, now that I took a look its clearer, thanks. \$\endgroup\$ – user1610950 Nov 24 '17 at 4:28

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