About five years ago, I wrote simple C extensions that our group has used on OS X, Linux, and Windows. Today, I'd probably use the Foreign Function Interface. Sometimes we used the KeySpan USB-Serial hardware with the same extension. It might be possible to do what you show below entirely in Racket, but the serial interfaces are sometimes quirky enough that a small, non comprehensive C library is easier to maintain.
rac On Dec 23, 2011, at 9:05 AM, Andrej Mošať wrote: > I was wondering how can one access serial port from scheme / racket? > To justify this ancient technology, more and more embedded devices, > microcontrollers and development boards are being used. UART, rs232, > serial over USB are being used to communicate with the devices. > There is some support in several OS by a few programming languages. > > Question: how can one reliably read / write to serial port from racket > under windows and linux ? > > Here are just some experiences. > > Sofar, Python has pyserial - works as a charm within minutes, > PERL claims to support rs232, > C++ and C have libraries, which vary by OS and are not standardized, > POSIX C++ seems to require the least amount of time to setup among > those. > > Linux can access serial port from command line by coreutils "stty" > program, as found in > http://planet.plt-scheme.org/package-source/xtofs/firmata.plt/1/0/ > i.e. > > (define port-name "/dev/ttyS0") > (system (string-append "stty -f " port-name " 57600 cs8 cread clocal") > > > Windows can directly read and write to serial ports by using mode and > reading / writing by copy, > here is a basic code example to do it from racket: > > #lang racket > ;c:\Program Files (x86)\GnuWin32\bin>mode com3: baud=115200 parity=N > data=8 stop=1 > ;copy com3 con > > (define port-name "com3") ;;serial port > (define baudrate 115200) ;;baud rate for port-name > > ;;; 1. set device parameters > ;; windows > (when (eq? (system-type 'os) 'windows) > (if (system (string-append "mode " port-name ":")) ;; detect if > device connected > (if (not (system (string-append "mode " port-name ": baud=" > (number->string baudrate) "parity=N data=8 stop=1")) ;; set the baud > rate and other params > ) > (error "Failed to open the connection with " port-name " > verify if your device is plugged in correctly") ;;error if device not > connected > 'OK_Baudrate_Set) > (error "Failed to open the connection with " port-name " verify > if your device is plugged in correctly") ;;error if device not > connected > ) > ) > > > Thank you very much for your thoughts and comments. > mosi > _________________________________________________ > For list-related administrative tasks: > http://lists.racket-lang.org/listinfo/users ____________________ Racket Users list: http://lists.racket-lang.org/users
