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by cbaurtx
Thu Feb 21, 2013 10:15 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Support for GPIO-driven interrupts
Replies: 47
Views: 86920

Re: Support for GPIO-driven interrupts

I would like to use one of the GPIOs to serve the interrupt of the pcf8574_keypad.c
key pad driver (This driver is part of the kernel). I have read that your patch is now
part of raspbian and I worry that I am not able to use one of the GPIOs with a separate
ISR. Am I wrong ?
by cbaurtx
Tue Sep 25, 2012 8:41 pm
Forum: Troubleshooting
Topic: Problem accessing the serial port (/dev/ttyAMA0)
Replies: 2
Views: 2681

Problem accessing the serial port (/dev/ttyAMA0)

I cannot access /dev/tty/AMA0 anymore. ls -l /dev/ttyAMA0 crwxrwx--- 1 root uucp 204, 64 Sep 25 22:10 /dev/ttyAMA0 [[email protected]]$ groups cb uucp audio users [[email protected]]$ cat /dev/ttyAMA0 cat: /dev/ttyAMA0: Permission denied obviously cb is member of uucp and should be allowed to access /dev/ttyAMA0. If I change...
by cbaurtx
Sun Aug 19, 2012 11:48 am
Forum: HATs and other add-ons
Topic: Keypad interface with ADP5589
Replies: 2
Views: 1905

Keypad interface with ADP5589

For one of my projects (Convert a broken boom box to an internet radio) I need to address several push buttons and switches. Using the Analog devices ADP5589 seems to be attractive for the following reasons: 1. There is a Linux driver for it 2. It connects via the i2c bus and not a single precious I...
by cbaurtx
Sun Aug 05, 2012 6:14 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: serial port with cts/rts
Replies: 14
Views: 9824

Re: serial port with cts/rts

I had a similar problems, but with a PC and a home built microcontroller system. The main issue was that the MCU was reset when booting the PC. So I added an optocoupler to only reset the MCU when RTS is set and some serial data are transmitted at the same time. This system works well with a Prolifi...
by cbaurtx
Sun May 20, 2012 1:42 pm
Forum: Other projects
Topic: [Q]hd44780 lcd screen
Replies: 53
Views: 47377

Re: [Q]hd44780 lcd screen

You can use a PCF8574P port extender which converts i2c to parallel. A detailed description is here: http://lcdproc.sourceforge.net/docs/stable-0-5-x-user.html#hd44780-i2c.circuit Also some HD44780 based LCD displays fashion a i2c interface already. I plan to go with the PCF8574P. You have to run th...
by cbaurtx
Mon Apr 23, 2012 8:05 pm
Forum: Other projects
Topic: Linux device drivers for Rapberry Pi on-board I/O
Replies: 97
Views: 55863

Re: Linux device drivers for Rapberry Pi on-board I/O

<r>Lars T. Hansen said: <br/> <br/> <br/> I and Paolo Palmieri had decided to begin developing 2 Linux device drivers for Pi's on-board I/O.<br/> <br/> Both I and Paolo are engineers (BEng) in embedded systems. I had made 2 (kernel space) drivers before (not in the kernel tree), and Paolo had done "...

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