4 replies to this topic

[NooM]

hello. the mini has an rs232 port, but its with a level shifter right? wich port is behind it? uart? if so, could i use another level shifter (max232) to connect to another device uart? greetings

[Nevyn]

the mini has an rs232 port, but its with a level shifter right?
wich port is behind it? uart?

if so, could i use another level shifter (max232) to connect to another device uart?

NooM,

If you look at the pin out cards in the Wiki you should be able to see which pins map to which ports and also the logic levels.

So, if you want to connect the Mini using COM2 to another device and that device used +/-12V logic then you would not need a converter. I'm sure you can work out the rest

Hope this helps,
Mark

[Joshk]

RS232 is the Mini's COM2. This tripped me up one night.

Here's my proven table for everyone's reference:
+----------------------------------------+
|PC's DB9 connector <-> Mini's COM2/RS232|
|----------------------------------------|
|..... 5 (GND)..... --- ..... 4 (GND)....|
|..... 2 (RX) ..... <-- ..... 1 (TX) ....|
|..... 3 (TX) ..... --> ..... 2 (RX) ....|
+----------------------------------------+

Please note RS232 signals swing from +12v (logic High) to -12v (logic Low). This is done so the signal can travel large distances and still be heard.
Hope this is handy. Up votes tell me this was useful for people.

[Paul Newton]

RS232 tip. RS232 was often used to connect a computer to a modem. The computer is referred to as a Data Termination Equipment or "DTE", and the modem is referred to as a Data Communication Equipment or "DCE". The DTE has a male connector, the DCE has a female connector. This is still seen on USB-RS232 adapters (the DB-9 end has pins). OK, so what's the tip? Everyone tends to remember that RS232 uses pins 2 & 3 for data, but most forget which is which. A DCE or modem should have a female DB-9 connector, and the tip is to remember that the data into the modem is the middle socket "pin 3". (There is only one middle because there are only 9 pins.) Well it helps me. Paul

[NooM]

thanks all, i understand that now (also with help from arron chapman) my plan is to use my usb -> uart cable on the minis rs232 port. so i need a max232 between them, cos the cable outputs logic level signals the parts arrive sonn, ill add another post how well it worked out than (but should do well, that has allready been done/tested)