Use of UEXT

[mikenycz]

I am looking at the A13-OlinuXino WIFI for a project that I am starting. One question about the UEXT. If I were to need two peripherals such as ethernet and an RS485 port, is there a way to implement both of these or is the UEXT a one extension port?

Thanks in advance,
Mike Nycz

[Lurch]

UEXT offers 1x SPI port, 1x I2C port and 1x UART port.
You can connect more than one I2C if the addresses are different, but generally only one SPI and/or UART.
If you have WiFi .... why would you need Ethernet?
Check if the RS485 uses any other pine than the UART, maybe it would work OK.
You could always use a USB ethernet and put the RS485 on the UEXT. (Olimex sells an USB ethernet module)

[dave-at-axon]

The RS485 connection uses 2 of the SPI lines (SCK #SS) to drive the TX/RX state.

You should be able to use I2C and RS485 at the same time.

[Greg L.]

The simple solution, if you need to use many UEXT modules, is to buy a UEXTx5 connector, right ?

[Lurch]

The UEXTx5 only allows you to plug in modules, it doesn't change anything on the pins.  So, you still have 1xSPI, 1xUART and NxI2C.  It is a better way to plug things in, though.