Go to advanced search

by kadamski
Tue Jun 04, 2013 9:07 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: i2c pulse stretch
Replies: 2
Views: 556

Re: i2c pulse stretch

Unfortunately, AFAIK it's not driver issue but hardware issue. As such, it may (but doesn't have to, maybe there is some workaround possible) be not fixable.
by kadamski
Tue Jun 04, 2013 8:49 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: i2c pulse stretch
Replies: 3
Views: 745

Re: i2c pulse stretch

You can also use software bitbanged GPIO driver. You need kernel recompilation for that currently, though. You can take a look at this thread for some more information.
by kadamski
Mon May 27, 2013 9:08 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Anyone interested in testing my avrdude with SPI support?
Replies: 23
Views: 7041

Re: Anyone interested in testing my avrdude with SPI support

Seems to be working with my atmega328p, using exacly the same wiring as for linuxgpio driver. I was able to properly read fuses and program some basic blink application. Great job! The only problem I have found (but I believe it may be in spi driver, not in your code) is that if I use linuxgpio driv...
by kadamski
Tue May 14, 2013 7:26 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: i2c configuration
Replies: 25
Views: 11212

Re: i2c configuration

Since you are using your own compiled kernel, you have to ensure that it is not overwriten by apt-get update. There are couple of ways you can achieve this. What I'm doing is to rename kernel.img to kernel-my.img and add kernel=kernel_my.img line to config.txt. This makes bootloader use kernel_my.im...
by kadamski
Tue May 14, 2013 3:28 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: i2c configuration
Replies: 25
Views: 11212

Re: i2c configuration

When you update the system with apt-get, your kernel may be updated (and it seems it was the case). The kernel consists of kernel.img file in /boot/ directory and of modules files in /lib/modules directory. It seems that you only overrides kernel.img file and not modules files. This causes your inco...
by kadamski
Mon May 13, 2013 6:36 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: i2c configuration
Replies: 25
Views: 11212

Re: i2c configuration

Check that you have w1-gpio and w1-therm kernel modules.
by kadamski
Sun May 12, 2013 7:40 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: i2c configuration
Replies: 25
Views: 11212

Re: i2c configuration

This is exacly what I was expecting when writing my last post in this thread. Good to hear that you managed to figure out yourself how to compile those modules. And by the way, the answer from SE that you quoted is actually mine. Noticed that in the middle of reading it :)
by kadamski
Fri May 10, 2013 11:22 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: i2c configuration
Replies: 25
Views: 11212

Re: i2c configuration

It's not distribution specific for sure. It may be kernel specific but I doubt it. I'm using latest raspbian image with my custom made kernel. And now that I think about this - this may be the cause of your problem. There is no gpio_pcf857x module in official raspberrypi's kernel. Are you able to lo...
by kadamski
Fri May 10, 2013 11:00 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: i2c configuration
Replies: 25
Views: 11212

Re: i2c configuration

I think I should have an entry "gpioXXX" in /sys/class/gpio after initializing the chip but I continue having the initial entries... Yes, you should have additional gpioXXX directory in /sys/class/gpio. And it works perfectly fine for me. But it only appears if i specify first argument to new_devic...
by kadamski
Thu May 09, 2013 7:36 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: i2c configuration
Replies: 25
Views: 11212

Re: i2c configuration

You can write anything you want as a frist argument to new_device. For example this wont give you an error: echo blah 0x20 > /sys/bus/i2c/devices/i2c-0/new_device Here's what I get from dmesg: i2c i2c-0: new_device: Instantiated device blah at 0x20 But of course it doesn't work. There is no driver f...
by kadamski
Thu May 09, 2013 4:28 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: i2c configuration
Replies: 25
Views: 11212

Re: i2c configuration

Are you sure that your device is pcf8574 and not pcf8574a or pca8574? Try those two as a first argument to /sys/bus/i2c/devices/i2c-1/new_device. Hint, you can remove previously created device using

Code: Select all

echo 0x3a >  /sys/bus/i2c/devices/i2c-1/delete_device
by kadamski
Wed May 08, 2013 3:57 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Bit-banged I²C kernel driver
Replies: 12
Views: 5948

Re: Bit-banged I²C kernel driver

You did everything right. 500/udelay comes from kernel documentation (include/linux/i2c-gpio.h). It does not work well for RaspberryPi, though. udelay value is a time in microseconds that scl should be low or high. This value is passed to udelay() kernel function that should sleep that long. So in o...
by kadamski
Fri May 03, 2013 9:57 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Bit-banged I²C kernel driver
Replies: 12
Views: 5948

Re: Bit-banged I²C kernel driver

There is a little hack in the code to check for errors when adding the bus. It is not working correctly, I have to investigate this. As a workaround, please add "sleep 0.5" just before "add_bus" line.
by kadamski
Thu May 02, 2013 7:39 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Bit-banged I²C kernel driver
Replies: 12
Views: 5948

Re: Bit-banged I²C kernel driver

Could you please show me the script you are using? And could you check dmesg to see if there are any error messages there?
by kadamski
Tue Apr 30, 2013 6:11 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Bit-banged I²C kernel driver
Replies: 12
Views: 5948

Re: Bit-banged I²C kernel driver

First the easiest question - in order to create the bus on system startup you can add insmod command to /etc/rc.local file. If you need some more busses, add apriopriate echo lines too. As for the restrictions - the only restrictions that I coded in the module is that you can't use pin 5 or 6. Using...
by kadamski
Thu Apr 25, 2013 3:15 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Enable both I2C Busses
Replies: 58
Views: 25998

Re: Enable both I2C Busses

Without having done any experimentation my feeling is that it would be much simpler if we had another set of busses running - but if it isn't possible then that's a non-starter. You could use software (bitbanged) I²C bus provided by i2c-gpio kernel module. Using my module from here you can easily s...
by kadamski
Tue Apr 16, 2013 10:10 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Bit-banged I²C kernel driver
Replies: 12
Views: 5948

Bit-banged I²C kernel driver

I've made a handy kernel module for everybody wanting to use bit-banged host instead (or in addition to) hardware one. It's like a wrapper for i2c-gpio kernel built-in module that let you dynamically create and remove i2c hosts on different gpio pins. It can be handy if you experience problems with ...
by kadamski
Mon Apr 15, 2013 9:37 am
Forum: Advanced users
Topic: Overclocking, CMA, and config.txt parameters
Replies: 2
Views: 3215

Re: Overclocking, CMA, and config.txt parameters

Overclocking part: Linux indeed has cpufreq mechanism for manipulating the frequency. It can't do this by magic, however. It has to have a driver. In case of a RaspberryPi, it's bcm2835-cpufreq driver (you can see the sources in drivers/cpufreq/bcm2835-cpufreq.c) in RaspberryPi specific kernel. If y...
by kadamski
Sat Apr 13, 2013 9:19 am
Forum: Advanced users
Topic: Wake from halt
Replies: 67
Views: 56361

Re: Wake from halt

Yes I was aware of where the power goes, that's why I was interested in the same measurement on model A. And I found it in the tread you linked to - 0.2W, not that bad. Now if only the LAN chip could be put in some deeper power safe mode..

Thanks for the link.
by kadamski
Thu Apr 11, 2013 9:51 am
Forum: Advanced users
Topic: Wake from halt
Replies: 67
Views: 56361

Re: Wake from halt

The Pi goes into a lower powered state. I was wondering how low the power usage is when RaspberryPi is halted. Connecting my multimeter, it seems that my model B takes about 110mA, which is 0.55W. It is almost 1/4 of the power consumption when turned on (and idle) but still quite high - it's almost...
by kadamski
Mon Apr 08, 2013 2:25 pm
Forum: Linux Kernel
Topic: RPi Kernel 3.8 Compilation
Replies: 2
Views: 4223

Re: RPi Kernel 3.8 Compilation

imagetool-uncompressed.py is not necessary anymore. Bootloader can boot Image or zImage directly nowadays.
by kadamski
Mon Oct 15, 2012 6:11 am
Forum: General discussion
Topic: Use initramfs?
Replies: 58
Views: 35663

Re: Use initramfs?

1) Maybe it was a building misconfiguration. I'll review it. It may also be a problem with the location bootloader puts initramfs file at. I didn't test the initramfs support for some time now. 2) Yes, I mean initramfs, not initrd, sorry. Do you think that ncurses problem causes the kernel panic? W...
by kadamski
Fri Sep 14, 2012 12:08 pm
Forum: Raspbian
Topic: ALSA on Raspbian
Replies: 167
Views: 154975

Re: ALSA on Raspbian

Unfortunately I don't know anything about espeak or using microphone. It seems to me that it first tries using ALSA, then jack, then PulseAudio but all fails. But I don't know why ALSA fails. For some reason it seems that it is trying to use dmix for capture stream which is not supported.
by kadamski
Fri Sep 14, 2012 11:14 am
Forum: Raspbian
Topic: ALSA on Raspbian
Replies: 167
Views: 154975

Re: ALSA on Raspbian

No, don't install PulseAudio, it makes more problems than it solves on RPi. It would be the best not to have any asound.conf file at start. Every change in this file is working next time you start some application using ALSA, no need for reboot.
by kadamski
Fri Sep 14, 2012 10:57 am
Forum: Raspbian
Topic: ALSA on Raspbian
Replies: 167
Views: 154975

Re: ALSA on Raspbian

Do you have PulseAudio installed? Do you have any .asound.conf or /etc/asound.conf files?

Go to advanced search