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by ezKleber
Sat Jan 03, 2015 4:55 pm
Forum: Bare metal, Assembly language
Topic: Question about GAS and macros
Replies: 0
Views: 396

Question about GAS and macros

Hi guys, I was trying to reduce some overhead in my code by eliminating function calls to get GPIO_BASE_ADDRESS and SYS_TIMER_BASE_ADDRESS and instead create some macros and "defines" (.equ or .set in ASM). The thing is that I noticed (I know this is an obvious thing, but still intrigued me) that -a...
by ezKleber
Sat Dec 20, 2014 5:35 pm
Forum: Bare metal, Assembly language
Topic: (Another) 7-segment display driver in assembler
Replies: 1
Views: 777

(Another) 7-segment display driver in assembler

Hi guys, I know that there have been posted lots of examples of driving a 7-segment display but, well, I feel like sharing mine too. I've been working with D323G, which has two digits controlled with nine pins: two are the common-anode part, which can control the digit to be displayed, and the other...
by ezKleber
Thu Jan 02, 2014 9:58 pm
Forum: Bare metal, Assembly language
Topic: DHT11
Replies: 0
Views: 913

DHT11

Hi! I'd like to play a bit with interrupts, and I'm planning on making a small program that is able to read the data of a DHT11 sensor (see the datasheet here ). My architecture is something like this: + Create an interrupt routine that detects the edges of the signal and stores the value of the sys...
by ezKleber
Tue Apr 02, 2013 11:34 am
Forum: Bare metal, Assembly language
Topic: Memory Paging
Replies: 16
Views: 6379

Re: Memory Paging

I've seen that most of the kernels have a look-up table different for each process: in every process-table there shall then be a region where peripherals are mapped as aforementioned, right? On the simpler OSs it might be done like that. But more usually, a process that wants access to a peripheral...
by ezKleber
Tue Apr 02, 2013 8:17 am
Forum: Bare metal, Assembly language
Topic: Memory Paging
Replies: 16
Views: 6379

Re: Memory Paging

So, let's see if I got this clear: basically, you can control how MMU acts by its look-up table. So, you (the SO when available, or you directly in your bare-metal program) can modify this table so: Addresses related to peripherals are: Available for everyone (not protected) Mapped directly (virtual...
by ezKleber
Mon Apr 01, 2013 9:49 pm
Forum: Bare metal, Assembly language
Topic: Memory Paging
Replies: 16
Views: 6379

Re: Memory Paging

First of all, I'd like to say how amazing the PI is: for me, it has always been a mystery how a computer worked. I mean, I build up an ALU back in University, and I had some rough idea of how computers worked... but now that I have a Pi I'm really getting into it. I've been reading some books about ...
by ezKleber
Thu Feb 07, 2013 8:47 pm
Forum: Camera board
Topic: STICKY: Foundation (old) Camera Board information
Replies: 446
Views: 292733

Re: Foundation Camera Board information

It would be cool if it can be used for astrofotography, as someone already posted. If it comes with the IR filter, it will not be a good choice for deep space, but maybe a low-cost solution for planetary...
by ezKleber
Mon Jan 28, 2013 2:04 pm
Forum: General programming discussion
Topic: Raspberry Pi "thermal_zone0/temp" issue
Replies: 2
Views: 610

Raspberry Pi "thermal_zone0/temp" issue

Hi, I've been doing some scripting to gather cpu load average and temperatures at regular intervals of 1 min. The thing is that, for time to time (at least one of the measures per day), the temperature registered is, or negative (bigger than -1kºC), or 85ºC. http://pi.meruelo.com.es/img/temp.png Bot...

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