What is the maximum SAFE baud rate i can squeeze out of the mega serial interfaces.? I have a sim 7000 connected on serial port 3 and my system serial port 0. Want to connect to maximum speed to send images over tcp.
Sounds like a perfect question for google! 115200
I found 250K to be a zero-error baud with a good balance between speed and interrupt rate.
My regular baud rate for my Arduinos is 500,000.
The Atmega datasheets say that the 16MHz MCUs will work up to 1,000,000 without error.
...R
Thank you for the replies.
I had to go in detail with the baud rate setting to match both arduino and sim7000 module.
And according to the atmega2560 datasheet, it can safely operate upto 1M bps at 16Mhz. But sim7000 has different values.
The values that match for both above 115200 is only 230400, nothing above that would match both the controller and the sim7000, so i guess i can only go upto 230400.
I havent tried this yet but in theory it seems legit. Please correct me if i am wrong.
If you look at the table of baud rate settings in the Atmega 2560 datasheet (Table 22-12 in my copy) you will see that it has bigger timing errors at 230400 baud than at 250k. This is just a function of the 16MHz clock rate. With an 18.4320MHz clock there would be no error at 230400 - but Arduinos work at 16MHz.
Consequently you may find that communication with your sim7000 is unreliable at 230400 baud. Even though there is also a timing error at 115200 baud the fact that it is slower should mask that.
...R
Yes. Its just that i am trying to send a 5kb image in blocks over sim7000, and it takes around 14 sec to do it. I am wondeirng if i try increasing my resolution, it is going to take forever to upload images. Increasing the baud rate would had helped in a huge way. But i guess i got to stick with 115200. Unless we design our own board in the future and improvise the crystal on it.
ammarqs:
Yes. Its just that i am trying to send a 5kb image in blocks over sim7000,
That sounds like a task better suited to a RaspberryPI than an Arduino.
...R