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by colbhaidh
Sat Jul 28, 2012 10:34 am
Forum: Advanced users
Topic: Overclocking
Replies: 1125
Views: 620327

Re: Overclocking

Over voltage is the really dangerous move. At final test after the IC is packaged, the test will guard band the speed. So, for example, it may be tested at 1GHz to guarantee that anything that would fail at 900MHz (if that was the spec) would never get through. So you may find your IC works OK at 95...
by colbhaidh
Tue Jul 17, 2012 3:25 pm
Forum: General programming discussion
Topic: Assembler Only
Replies: 4
Views: 1909

Assembler Only

Why not have a dedicated programming forum for assember? Anyone interested?
by colbhaidh
Mon Jul 16, 2012 3:01 pm
Forum: C/C++
Topic: GNU assembler problem.
Replies: 6
Views: 1926

Re: GNU assembler problem.

Switch .bss to .data for variables you do wish to initialise prior to the program running.

I think this is what the problem is. If not, post some more of your code.
by colbhaidh
Mon Jul 16, 2012 2:50 pm
Forum: C/C++
Topic: GNU assembler problem.
Replies: 6
Views: 1926

Re: GNU assembler problem.

Och sorry, put a .bss statement before your local varaibles. Note that these are all set to zero upon execution so you cannot pre-initialise them. .global main main: push {ip,lr} ldr r0,=message bl printf ldr r3,=alan @r3 = address of alan ldr r1,[r3] @r1 = contents of address pointed to by r3 ldr r...
by colbhaidh
Sun Jul 15, 2012 5:43 pm
Forum: C/C++
Topic: GNU assembler problem.
Replies: 6
Views: 1926

Re: GNU assembler problem.

Can you post more code?
The following works withpout any issue:

Code: Select all

    .global main
main:
    push    {ip, lr}

	mov r0,#34
	adr r0,fred
	
    ldr     r0, =message
    bl      printf
    mov     r0, #0      @ Return 0.
    pop     {ip, pc}

message:
    .asciz  "Gone yurself tam.\n"
fred:
	.word 0
 
by colbhaidh
Sat Jul 07, 2012 3:14 pm
Forum: General discussion
Topic: Dead Pi's
Replies: 7
Views: 1436

Dead Pi's

I am quite happily running my Raspi-pi (about 4 weeks now) but I am reading a lot of comments about raspberry pi's dying - should I be worried?
by colbhaidh
Wed Nov 02, 2011 10:08 am
Forum: General discussion
Topic: DRAM on USB
Replies: 9
Views: 4068

Re: DRAM on USB

Should be quite straight forward to build one using the PIC18F microcontroller although the speed would be limited to 12Mb/sec for consecutive reads or writes.
by colbhaidh
Wed Nov 02, 2011 9:48 am
Forum: Staffroom, classroom and projects
Topic: Fond memories
Replies: 42
Views: 11246

Re: Fond memories

<t>You guys make me feel really old. My first computer experience was on an IBM 370 main farme programming in Fortran using punch cards in Glasgow after school hours. Getting the average of 5 numbers could take all night.<br/> 1st personal computer was an Acorn Atom kit (4K RAM) followed by a TI99/4...
by colbhaidh
Thu Oct 27, 2011 7:47 am
Forum: Off topic discussion
Topic: USB - RS232 - TTL connection
Replies: 6
Views: 4549

Re: USB - RS232 - TTL connection

<r>The Tx voltage from the USB to RS232 will be +/-12V or at least > +/- 8V so you must not connect it directly to the 3.3V logic pins. You need to build a small voltage dwon converetot and up convertor. Details can be found here <URL url="http://picprojects.org.uk/proj.....O/ssio.htm">http://picpro...
by colbhaidh
Tue Oct 25, 2011 8:23 am
Forum: General discussion
Topic: STICKY: Introduce yourself!
Replies: 3626
Views: 175992

Re: Introduce yourself!

<t>I'm Stephen, one of the auld scottish gits. First byte was a 6800 in Glasgow University ( ... Physics lab believe it or not!). Acorn ATOM then BBC (which I still use today) Powertran Cortex. I remember the start of Linux back in early 90's and hooked since then. Mostly program in assembly languag...

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