Re: [Lcd4linux-devel] display on WRAP-Board - how fast is i2c? ho w good is the lpc connector?

[Stefan K. <ste...@cr...>]

Hi Luis,

Luis.F.Correia schrieb am 25.07.2006 11:47:
> 
> They are needed to pull up the I2C lines at 3.3V, this is a requirement from
> the I2C specifications.

o.k. - for the rest of the readers - I provide your schematics as ascii:

  VCC
   +            .------------.     .------------.
   '----o---o---|16         1|--.  |            |
        |   |   |    PCF8574 |  |  |        LCD |
       .-. .-.  |           2|--o  |            |
       | | | |  |            |  |  |            |
       | | | |  |           3|--o  |            |
       '-' '-'  |            |  |  |            |
        |   |   |            | === |            |
        |   |   |            | GND |            |
  SDA o-o---)---|15          |     |            |
            |   |           4|-----|D4          |
  SCL o-----o---|14          |     |            |
                |           5|-----|D5          |
   .------------|8           |     |            |
   |            |           6|-----|D6          |
  ===           |            |     |            |
  GND           |           7|-----|D7          |
                |            |     |            |
                |      10  9 |     | RS  E   RW |
                '------------'     '------------'
                       |   |         |   |   |
                       |   '---------'   |  ===
                       '-----------------'  GND

>> I wired my display like yours. I configured lcd4linux as
>> 
>> Display DOG-16x3 {
>>     Driver 'HD44780'
>>     Model 'generic'
>>     Bus 'i2c'
>>     Device '64'

is that correct? It's the address of the chip?

>>     Port '/dev/i2c-0'
>>     Icons '8'
>>     Size '16x3'
>> 
>>     Wire {
>>         RW        'GND'
>>         RS        'AUTOFD'
>>         ENABLE    'STROBE'
>>     }

That's wrong! It should be

Wire {
     RW        'GND'
     RS        'DB4'
     ENABLE    'DB5'
}

Isn't it?

> you'll need to add the specific /dev entries.

Be free to provide me wiht your major/minor numbers. My devices are
currently

ls -al /dev/i2*
crw-r--r--    1 root     root      89,   0 Jul 25 13:06 /dev/i2c-0
crw-r--r--    1 root     root      89,   1 Jul 25 13:06 /dev/i2c-1

> In WRAP, the temp sensor sits on bus 1, while the external bus is
> bus 0. You are getting different results because you are using the 
> in kernel I2C drivers. The WRAP board uses the 'worng' values for the
> I2C AccessBus controllers. Please check in the driver I previously
> sent to get the proper I/O ports. You may have to patch the I2C 
> driver to match this board (scx200_acb i mean).

Don't know what you want me to do ... Sure I'm using the in-kernel i2c
driver. It works fine. I do not want to make changes in the kernel modules.

> With lcd4linux, you will only need the i2c-core, i2c-dev, i2c-proc 
> and the access bud driver.
> 
> Nothing else is needed, because we do RAW chip access.

Do the already loadesd modules affect lcd4linux?

> Can you post the dmesg messages?

No, there is no dmesg in fli4l - but I have a full bootlog - what do you
expect to see?

MfG

Stefan