Communication between computer and MCU - Page 1
Forum section: electronics / beginners

author: Yaro
author_rank: Contributor
timestamp: March 18, 2015, 02:27:49 pm
content: Hi all,I want to ask if there is another communication way between an MCU and a computer faster than RS232 with USB. I want to try to have a faster communication(over 115200baud) and if possible with something already done(or in part done).

author: martijnb
author_rank: Newbie
timestamp: March 18, 2015, 02:39:20 pm
content: According to this thread (http://www.avrfreaks.net/forum/what-maximum-baudrate-rs232), you should be able to reach your desired speed.Otherwise, you could take a look at RS232's bigger brother, RS-422 or RS-485.Wikipedia states that RS232 supports speeds from 100 kbit/s to 10 Mbit/s, which is plenty.

author: ggchab
author_rank: Frequent Contributor
timestamp: March 18, 2015, 02:43:17 pm
content: I am using a cheap RS-232 PCI board in my PC. That's a lot faster than RS-232 / USB adapter.

author: katzohki
author_rank: Frequent Contributor
timestamp: March 18, 2015, 02:43:51 pm
content: There are MCUs that support USB directly.

author: suicidaleggroll
author_rank: Super Contributor
timestamp: March 18, 2015, 02:47:19 pm
content: Why are you using RS232 with USB in the first place?MCUs don't speak RS232, and modern computers all have USB, so what is RS232 doing in the mix at all? FTDI makes plenty of USB to UART adapters that run up into the double digit Mbps, will that not work for you?If it's a long distance run you're worried about, then go with something like 422 or 485 instead.

author: codeboy2k
author_rank: Super Contributor
timestamp: March 18, 2015, 10:51:40 pm
content: Quote from: suicidaleggroll on March 18, 2015, 02:47:19 pmI think generally people confuse serial comms with meaning RS232 comms. And the FTDI chips have 232 in the name, even though they are just USB to serial chips intended to talk to the MCU's serial port.

author: Yaro
author_rank: Contributor
timestamp: March 19, 2015, 10:42:46 am
content: Maybe I didn't explain well. I've a board that have a usb communication limitation to 115200 baud in the firmware. What I want is an alternative method using GPIOs to send data to a PC. I know I can use USB, but use this standard without libraries and hardware support will be long to develop. I'm asking something, already done, that allow me to have faster communication with a PC.

author: Kjelt
author_rank: Super Contributor
timestamp: March 19, 2015, 10:50:39 am
content: Quote from: Yaro on March 19, 2015, 10:42:46 amWell unless you create your own proprietary communication interface to the PC your only off the shelf alternative would be to use IP.Commercial readytogo IP modules often have the same lame serial interface, which is good but not fast as you would like.So to do this cheap and quick I would use a raspberry pi, interface its GPIO with your microcontrollerboard (use a proprietary interface and protocol) and transmit/receive through tcp or udp (if package loss is acceptable) over IP.

author: Psi
author_rank: Super Contributor
timestamp: March 19, 2015, 11:11:29 am
content: FTDI's FT220X usb to spi IC can do 500kbits/shttp://www.ftdichip.com/Products/ICs/FT220X.html

author: katzohki
author_rank: Frequent Contributor
timestamp: March 19, 2015, 06:55:14 pm
content: Quote from: Yaro on March 19, 2015, 10:42:46 amThere are devices that will support USBdirectly.What do you need to send data so fast for?

author: Rory
author_rank: Frequent Contributor
timestamp: March 19, 2015, 08:16:57 pm
content: For USB virtual com ports, CP2102 will go to 1 Mbps. FT2232D can do async serial or 8 bit parallel I/O which can be considerably faster.