Using the built-in UART (pins 1 and 0)

Forum 2005-2010 (read only) Hardware Interfacing
1

I'm trying to interface with this serial camera (http://www.electronics123.com/s.nl/it.A/id.2027/.f?sc=8&category=241). The datasheet and user manual are somewhat confusing since it says that the device will automatically detect the baud rate, but then says to use 14400bps with the sync command. I haven't had any luck communicating with it over SoftwareSerial at 9600bps and am thinking I'll need to connect it directly to the 0 and 1 pins and use the built-in UART at 14400bps.

I'm using the Arduino Wee, from Sparkfun (Wee (Compatible with Arduino) - DEV-08737 - SparkFun Electronics), which is powered through the USB line. When I connected the camera to the 0 and 1 pins it still would not complete the sync. Could being connected to the USB and having the Serial Monitor running affect communication with the camera?

How should I approach and troubleshoot this problem? Would it be better to get an external UART chip?

Thanks.

2

Since the camera docs say that it is designed to talk to a PC serial port, you probably need some sort of rs232 driver between it and the arduino...

3

You've got the right protocol, but the wrong voltage levels. You need something like this:
http://www.coolcomponents.co.uk/catalog/product_info.php?cPath=27&products_id=158&osCsid=44b93e7726db2fe7c2bec8c0c3f9997d

4

The camera docs say 3.3V, so that indicates to me logic level not RS232 level (since they are at logic voltages not RS232 voltages). But I could be wrong.

Since the arduino Wee is a 3.3V device, you don't need any adapter - connect TX to RX, RX to TX, and GND to GND and you should be good to go. Since the camera only draws 60mA, you can probably power it from the Wee's 3.3V regulator as well.

If you want to hook the camera to a PC to play with it, you will need that aforementioned adapter, and a regulated power supply as well.

-j

5

I think you are right about that, i was just looking at the text next to the picture, saying RS232.
The reference to an evaluation board to get true rs232 from the cam below that picture indicates that you should actually have the 3V and can do the connection 1:1 to the arduino.

6

You might want to use this: