MEGA2560 feature feasibility - RS232 for communication and sketch upload

Projects General Guidance
1

I have a RS232 only requirement with a project and I would like to be able to talk to my project while retaining the ability to upload sketches. Same cable, same plug.

If I understand the MEGA2560 as it is currently, the 32u2 handles that from a USB point of view. I have no problem adding another chip to my project, is there something already created that accomplishes this?

Thanks
Michael Pless

2

You mean like an RS232 adapter?
http://www.nkcelectronics.com/rs232-to-ttl-converter-board-33v232335.html
http://www.nkcelectronics.com/RS232-to-TTL-converter-board-DTE-with-Male-DB9-33V-to-5V_p_369.html
connect to another serial port on the mega (Serial1, Serial2, Serial3)

3

Im using a MAX3232 to connect the serial-0 to the mega2650 chip, I can talk to my project like this but I cannot update the sketch.

Any ideas?

4

You have a bootloader installed? You are resetting the chip to start the bootlaoder up to look for an incoming data message to start the download?

5

ok now were getting somewhere! I do have the factory boot loader installed. Is there a way to reset the mega with out the DTS pin on the serial port? I have access to TX,RX,GND,CTS, and RTS.

If that is NOT possible I can place a dual UART mega chip to intercept and when an upload is detected to initiate the reset. Has someone already done something like this?

Thx

6

Is there a way to reset the mega with out the DTS pin on the serial port?

Reach over and press the reset button?

7

In case anyone reads this thread and wonder what the result was...

My enclosure is locked and I am not able to modify or manually hit the reset button.
I ended up adding a relay that could be switched externally that enabled the DTS pin to be connected to reset.
With the switch off I could connect and disconnect from the Mega chip and it would not reset me. With the switch on I could do a sketch update and the auto reset would be working properly.