USB TTL connector to Olinuxino A13 UART ?

Started by buzibus, January 26, 2013, 03:46:49 am

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buzibus

January 26, 2013, 03:46:49 am Last Edit: January 26, 2013, 03:52:38 am by buzibus
Hello,

I've a USB to TTL converter like many of those sold cheaply in ebay and other places.

Those adapters connect to a computer USB port and (with an installed driver) simulate a RS232 output with 4( or 5) pins: 3v/5v, GND, TX, RX.

I use it for programming microcontrolers like the LPC1114 that have ISP.


Can I use it to connect my PC/Laptop to my Olinuxino ?

The connection should be something like:


USB 2 TTL GND  ----  GND olinuxino
USB 2 TTL TX   ----  RX olinuxino
USB 2 TTL RX   ----  TX olinuxino


Would this work ? should the 3.3v pins be connected too ?



Thanks in advance



EDIT:


For reference, the USB to TTL adapter looks like this:





the pins usually are labelled 5v, 3.3v ( there's usually some type of regulator ), TX, RX, GND and Reset.

JohnS

Yes it should work.  You ought to check how the power (+3/5) is connected and if the chip needs 3 or 5, and connect as appropriate.  Mine is similar but different chip which needed 3.3V so I connected that (thus, 4-wires connected) and it's good.

You may get Tx & Rx the wrong way round.  So long as you've figured the above out just try them the other way.

John

buzibus


AFAIK the + pins should not be connected as, only the GND pins

the A13 will get power from the wall-wart adapter, and the USB dongle from the USB connection to the computer


TX goes to RX and RX to TX :)



I need to try this out soon, or just buy the olimex adapter cable

JohnS

For sure try it without + but realise that some adapters need power from the non-USB end in which case you need to connect + and will need to make sure the voltage is right.

The "standard" for where Rx & Tx go is abused so often that you should not be surprised if you have toswap the connectors.