linux

PIC18: PCF8563 I2C Real Time Clock Calendar

rtcc clock calendarThe Freedom II demoboard includes also a PCF8563 I2C Real Time Clock Calendar (RTCC); let's learn how to use it to display time and date and set an alarm.

PIC18: I2C EEPROM dump via RS-232 serial

In this project we are going to implement two different buses to get data from and to a PIC18: serial RS-232 and I2C bus. For an intro to I2C please see Wikipedia; the scenario that was implemented below is the one in which the PIC operates in master mode.

PIC18: branch instructions

binary codeSkimming through the PIC 18F4550 istruction set we can see, among others, a bunch of branch instructions.

What are they for and what's their relationship with the STATUS register? Let's see them in practice using some assembly code examples. This will also be a nice occasion to do a bit of simple HEX math.

Branch instructions

BC - Branch if Carry

BN - Branch if Negative

PIC18: a guide to assembling, linking and programming with Linux

microchip pic linux tuxHave you ever wondered how to program Microchip PICs in assembly under Linux? Here's a quite in-depth introduction that tries also to show the inner workings of the PIC18 family architecture.

We'll start to see how modular assembly is using relocatable code and how cool it is working at this low level, so low that we can understand how PICs think and work!

Formattazione Output: Cut

Supponiamo di avere un file di testo con un elenco, una piccola tabella con campi delimitati dal carattere ':'

$ cat elenco001.txt 

406378:Sales:Itorre:Jan
031762:Marketing:Nasium:Jim
636496:Research:Ancholie:Mel
396082:Sales:Jucacion:Ed

Lavorare con i campi

Se volessimo elencare solo i valori del 1° campo:

$ cat elenco001.txt | cut -d":" -f1

406378
031762
636496
396082

Con '-d' si stabilisce un delimiter dei campi (in questo caso ':').

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Formattazione Output: Awk e Sort

Supponiamo di dover elencare dei file ordinandoli per dimensione; l'output dovrà essere :

1) ls dei file

Prima di tutto diamo ls con gli opportuni parametri:

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DNS e BIND

dns zone

Record NS

Quando un name server riceve una richiesta di risoluzione nome e non ha in cache il risultato dell'interrogazione deve interrogare i name server autoritativi per la zona. I NS autoritativi sono sia il primary che gli slave; non c'è differenza tra i due per questo tipo di interrogazione.

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