speciousfool - Developer IT

Connecting to MSP430 via /dev/ttyACM0

- by speciousfool

I'd like some suggestions about how to fix garbled serial output from a device connected on /dev/ttyACM0. Lately I've been working on a development project making use of TI's MSP430 microcontroller (specifically the eZ430-RF2560). Over on this thread you can see we've been testing some code and have found that the output of the microcontroller over serial is garbled. The btstack provides simple counter test program. When we run the program and look at the serial port output using PuTTY on Windows 7 we see: rfcomm_send_internal cid 117 doesn't exist! BTstack counter 26230 rfcomm_send_internal cid 117 doesn't exist! BTstack counter 26231 However if we connect from various Ubuntu clients we get something like: Stt.R. BTacn 0 BTacn 002BTacn 0 BTcct 04BTtacoe 5BTacun My current belief is that this is because the device is being detected by cdc_acm as a generic USB ACM device. Another thread about a similar microcontroller suggests that the device should use a specific usb serial driver. We've verified that the module is compiled on our system and did a "modprobe ti_usb_3410_5052" but this had no effect on cdc_acm. Here is the relevant section of the kernel's debug log: [ 2735.092987] usb 2-1.2: new full speed USB device number 5 using ehci_hcd [ 2735.213655] cdc_acm 2-1.2:1.0: This device cannot do calls on its own. It is not a modem. [ 2735.213669] cdc_acm 2-1.2:1.0: No union descriptor, testing for castrated device [ 2735.213720] cdc_acm 2-1.2:1.0: ttyACM0: USB ACM device [ 2745.241996] generic-usb 0003:0451:F432.0003: usb_submit_urb(ctrl) failed [ 2745.242023] generic-usb 0003:0451:F432.0003: timeout initializing reports [ 2745.242401] generic-usb 0003:0451:F432.0003: hiddev0,hidraw0: USB HID v1.01 Device [Texas Instruments Texas Instruments MSP-FET430UIF] on usb-0000:00:1d.0-1.2/input1 So, in summary, we'd like to figure out how to properly connect to this device. Also of use may be the appropriate place to file a bug report.

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How to reshape matrices in Mathematica

- by speciousfool

When manipulating matrices it is often convenient to change their shape. For instance, to turn an N x M sized matrix into a vector of length N X M. In MATLAB a reshape function exists: RESHAPE(X,M,N) returns the M-by-N matrix whose elements are taken columnwise from X. An error results if X does not have M*N elements. In the case of converting between a matrix and vector I can use the Mathematica function Flatten which takes advantage of Mathematica's nested list representation for matrices. As a quick example, suppose I have a matrix X: With Flatten[X] I can get the vector {1,2,3,...,16}. But what would be far more useful is something akin to applying Matlab's reshape(X,2,8) which would result in the following Matrix: This would allow creation of arbitrary matrices as long as the dimensions equal N*M. As far as I can tell, there isn't anything built in which makes me wonder if someone hasn't coded up a Reshape function of their own.

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DrScheme versus mzscheme: treatment of definitions

- by speciousfool

One long term project I have is working through all the exercises of SICP. I noticed something a bit odd with the most recent exercise. I am testing a Huffman encoding tree. When I execute the following code in DrScheme I get the expected result: (a d a b b c a) However, if I execute this same code in mzscheme by calling (load "2.67.scm") or by running mzscheme -f 2.67.scm, it reports: symbols: expected symbols as arguments, given: (leaf D 1) My question is: why? Is it because mzscheme and drscheme use different rules for loading program definitions? The program code is below. ;; Define an encoding tree and a sample message ;; Use the decode procedure to decode the message, and give the result. (define (make-leaf symbol weight) (list 'leaf symbol weight)) (define (leaf? object) (eq? (car object) 'leaf)) (define (symbol-leaf x) (cadr x)) (define (weight-leaf x) (caddr x)) (define (make-code-tree left right) (list left right (append (symbols left) (symbols right)) (+ (weight left) (weight right)))) (define (left-branch tree) (car tree)) (define (right-branch tree) (cadr tree)) (define (symbols tree) (if (leaf? tree) (list (symbol-leaf tree)) (caddr tree))) (define (weight tree) (if (leaf? tree) (weight-leaf tree) (cadddr tree))) (define (decode bits tree) (define (decode-1 bits current-branch) (if (null? bits) '() (let ((next-branch (choose-branch (car bits) current-branch))) (if (leaf? next-branch) (cons (symbol-leaf next-branch) (decode-1 (cdr bits) tree)) (decode-1 (cdr bits) next-branch))))) (decode-1 bits tree)) (define (choose-branch bit branch) (cond ((= bit 0) (left-branch branch)) ((= bit 1) (right-branch branch)) (else (error "bad bit -- CHOOSE-BRANCH" bit)))) (define (test s-exp) (display s-exp) (newline)) (define sample-tree (make-code-tree (make-leaf 'A 4) (make-code-tree (make-leaf 'B 2) (make-code-tree (make-leaf 'D 1) (make-leaf 'C 1))))) (define sample-message '(0 1 1 0 0 1 0 1 0 1 1 1 0)) (test (decode sample-message sample-tree))

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Using a filename with spaces with scp and chmod in bash.

- by speciousfool

Periodically, I like to put files in the /tmp directory of my webserver to share out. What is annoying is that I must set the permissions whenever I scp the files. Following the advice from another question I've written a script which copies the file over, sets the permissions and then prints the URL: #!/bin/bash scp "$1" SERVER:"/var/www/tmp/$1" ssh SERVER chmod 644 "/var/www/tmp/$1" echo "URL is: http://SERVER/tmp/$1" When I replace SERVER with my actual host, everything works as expected...until I execute the script with an argument including spaces. Although I suspect the solution might be to use $@ I've not yet figured out how to get a spaced filename to work.

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On what platform did these popular programming languages originate?

- by speciousfool

Perhaps you know the story of HTTP and HTML being developed on a NeXT computer. I am curious which platform served as the first home for these programming languages: Ada C C++ C# D Erlang Fortran Haskell Java Javascript Lisp Logo MATLAB ML Perl PHP Prolog Python R Ruby Scheme SQL Smalltalk I thought it might be interesting to reflect on how the machine and operating environment lead to different design decisions. Or to see if some architecture or operating system variant was particularly fruitful for programming language development. A question for the historians among us.

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