midge.vlad.org.ua :: View topic

Posted: Fri Jan 19, 2007 1:35 pm Post subject: I2C info

In the latest svn toolchain the newest i2c driver are available.

With this driver you can use ANY gpio or switch led line for scl/sda !
Default is scl = gpio1 and sda = gpio3. This can changed in the kernelkonfig
or you load the driver with parameter "scl=x sda=y" for gpio x and y.
0..7 are the real gpios (depend on PLCC or BGA chip not all gpios are wired)
8..22 are the switch leds (3 leds per port, on BR6104K only 2 leds per port are connected !)
You must change with 4M-flash mod!

With use of the switch led lines its not needed to solder the very small ADM5120-pins.
You can load the driver several time, so you can drive several i2c-busses (-o paramter from insmod).
The i2c system is also updated to version 2.10.1.
To compile the lm_sensors tools please see on my site.
I have tested the tools i2cget, i2cset, eeprog, eeprom, eepromer, sensors and the driver for PCF8591 (4xADC/1xDAC) and LM75.
Libsensors is also available.
The lcd4linux can use the i2c to drive a lcd via a PCF8574(A).
My router now has a PCF8583 RTC and set the date/time on boot time
without internet connection.

Please do not forget the pullup-resistors ! The leds are NOT enough ! Solder a resistor in parallel.
_________________
2x Edimax BP6104K + USB-Mod
I2C-Bus with 40x2 LCD, RTC, ADC, DAC

Posted: Fri Jan 19, 2007 2:54 pm Post subject:

What you think, is possible to write kernel driver to implement serial interface via GPIO ?

Posted: Fri Jan 19, 2007 3:06 pm Post subject:

Posted: Fri Jan 19, 2007 6:22 pm Post subject:

@vlad
Sorry Im a beginner for C programms and also a beginner for linux programming.
I dont know how to write a serial driver for linux.
My work with the i2c and the coming led driver is only to modify a existing (simple) source.
But I think its not possible without additional UART-chips or similar because
a bit-bang driver do not work without a clock line.
Linux do not give a guarantee for time slice.
With a clock line like in I2C or SPI bus its no problem.
For what do you need additional serial interfaces ?

The next I will try to modify the mmc driver from WRT54. I hope its a
workaround for the "two usb devices problem". Then a usbserial converter can use better.

Other question, do you know the needed value for gpio 3 and 5 initializing with the 4M-flash mod ? I have no answer from dac922.

@MRX
Yes,
please see http://midge.vlad.org.ua/forum/viewtopic.php?t=350 and
http://translate.google.com/translate?u=http%3A%2F%2Fmidge.vlad.org.ua%2Fforum%2Fviewtopic.php%3Ft%3D450%26postdays%3D0%26postorder%3Dasc%26start%3D0&langpair=ru%7Cen&hl=en&ie=UTF8
The patch I have seen in the svn trunk, but I have no device or flash chip to test.
_________________
2x Edimax BP6104K + USB-Mod
I2C-Bus with 40x2 LCD, RTC, ADC, DAC

Posted: Sat Jan 20, 2007 9:09 am Post subject:

Posted: Sat Jan 27, 2007 7:23 pm Post subject:

I have made some simple test programs for driving these i2c chips -

1) LM75 thermometer
2) PCF8574 8 line port - set output lines
3) PCF8574 8 line port - read output lines
4) PCF8591 A/D and D/A - read one of 4 A/D lines and write to the D/A pin

All for any i2c bus address

You need the basic dl4huf i2c set-up on the Sweex/Edimax router

See pull down menu item 6 of my site below
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http://www.sunspot.co.uk/Projects/sweexproject.htm