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From: Laurent H. <lau...@fr...> - 2014-04-07 14:23:10
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Hi all
I'm currently trying to use lcd4linux on a WR703N router with OpenWRT,
with a 20x4 HD44780 LCD equipped with an I2C interface.
Unfortunately, after several hours of struggle, I finally found that the
I2C integrated (soldered) interface - model YwRobot LCM1602 - is
finally not compatible with the plain HD44780-I2C driver :-( I got the
same behavior as the TRAC ticket #295 described.
These LCD + interfaces are sold by many vendors (mostly Chinese etc.)
and under several brands.
Actually, the 4 bits of data are assigned to the 4 HIGHER bits of the
"abstracted Port", and RS, RW, and EN are assigned to the LOWER bits :-(
Here is the corresponding table between the PCF8574 output pins and the LCD
PCF 8574 LCD
Pin Function Pin Function
4 P0 4 RS
5 P1 5 RW
6 P2 6 EN
7 P3 NC (backlight ?)
9 P4 11 D4
10 P5 12 D5
11 P6 13 D6
12 P7 14 D7
From what I read on the HD44780 wiki page, in 4 bits mode, the data
bits are ALWAYS assigned to DB0-DB3, and it seems there is no way to
assign them to DB4-DB7 (which in turn are always assigned to control
signals).
Can you help ?
Thanks !
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From: Michael R. <mi...@re...> - 2014-04-10 16:40:49
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Hello Laurent,
Although I never owned nor used a HD44780-i2c-display, I had a quick look at the sources: i2c should support
"Soft-Wiring", this menas you shouldbe able to specify the signals in lcd4linux.conf
But I don't know the syntax :-) just try some of the examples from the normal wiring, usind onnly DB0..DB7
try to strat lcd4linux with -fvv, ond look in the output for occurences like
info("%s: wiring: [DISPLAY:%s]<==>[i2c:DB%d]", Driver, name, w);
the soft-wiring code is in drv_generic_i2c.c, function
unsigned char drv_generic_i2c_wire(const char *name, const char *deflt)
good luck! :-)
Am 2014-04-07 16:22, schrieb Laurent HAAS:
> Hi all
>
> I'm currently trying to use lcd4linux on a WR703N router with OpenWRT,
> with a 20x4 HD44780 LCD equipped with an I2C interface.
>
> Unfortunately, after several hours of struggle, I finally found that the
> I2C integrated (soldered) interface - model YwRobot LCM1602 - is
> finally not compatible with the plain HD44780-I2C driver :-( I got the
> same behavior as the TRAC ticket #295 described.
>
> These LCD + interfaces are sold by many vendors (mostly Chinese etc.)
> and under several brands.
>
> Actually, the 4 bits of data are assigned to the 4 HIGHER bits of the
> "abstracted Port", and RS, RW, and EN are assigned to the LOWER bits :-(
>
> Here is the corresponding table between the PCF8574 output pins and the LCD
>
> PCF 8574 LCD
> Pin Function Pin Function
> 4 P0 4 RS
> 5 P1 5 RW
> 6 P2 6 EN
> 7 P3 NC (backlight ?)
> 9 P4 11 D4
> 10 P5 12 D5
> 11 P6 13 D6
> 12 P7 14 D7
>
> From what I read on the HD44780 wiki page, in 4 bits mode, the data
> bits are ALWAYS assigned to DB0-DB3, and it seems there is no way to
> assign them to DB4-DB7 (which in turn are always assigned to control
> signals).
>
> Can you help ?
>
> Thanks !
>
> ------------------------------------------------------------------------------
> Put Bad Developers to Shame
> Dominate Development with Jenkins Continuous Integration
> Continuously Automate Build, Test & Deployment
> Start a new project now. Try Jenkins in the cloud.
> http://p.sf.net/sfu/13600_Cloudbees_APR
> _______________________________________________
> Lcd4linux-users mailing list
> Lcd...@li...
> https://lists.sourceforge.net/lists/listinfo/lcd4linux-users
>
>
--
Michael Reinelt <mi...@re...>
http://home.pages.at/reinelt
GPG-Key 0xDF13BA50
ICQ #288386781
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From: Benjamin F. <bfu...@go...> - 2014-04-12 17:09:13
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Hello Laurent,
did you have any success?
Am 10.04.2014 18:40, schrieb Michael Reinelt:
> Hello Laurent,
>
> Although I never owned nor used a HD44780-i2c-display, I had a quick look at the sources: i2c should support
> "Soft-Wiring", this menas you shouldbe able to specify the signals in lcd4linux.conf
>
> But I don't know the syntax :-) just try some of the examples from the normal wiring, usind onnly DB0..DB7
>
> try to strat lcd4linux with -fvv, ond look in the output for occurences like
>
> info("%s: wiring: [DISPLAY:%s]<==>[i2c:DB%d]", Driver, name, w);
>
> the soft-wiring code is in drv_generic_i2c.c, function
> unsigned char drv_generic_i2c_wire(const char *name, const char *deflt)
>
>
> good luck! :-)
>
>
> Am 2014-04-07 16:22, schrieb Laurent HAAS:
>> Hi all
>>
>> I'm currently trying to use lcd4linux on a WR703N router with OpenWRT,
>> with a 20x4 HD44780 LCD equipped with an I2C interface.
>>
>> Unfortunately, after several hours of struggle, I finally found that the
>> I2C integrated (soldered) interface - model YwRobot LCM1602 - is
>> finally not compatible with the plain HD44780-I2C driver :-( I got the
>> same behavior as the TRAC ticket #295 described.
>>
>> These LCD + interfaces are sold by many vendors (mostly Chinese etc.)
>> and under several brands.
>>
>> Actually, the 4 bits of data are assigned to the 4 HIGHER bits of the
>> "abstracted Port", and RS, RW, and EN are assigned to the LOWER bits :-(
>>
>> Here is the corresponding table between the PCF8574 output pins and the LCD
>>
>> PCF 8574 LCD
>> Pin Function Pin Function
>> 4 P0 4 RS
>> 5 P1 5 RW
>> 6 P2 6 EN
>> 7 P3 NC (backlight ?)
>> 9 P4 11 D4
>> 10 P5 12 D5
>> 11 P6 13 D6
>> 12 P7 14 D7
>>
>> From what I read on the HD44780 wiki page, in 4 bits mode, the data
>> bits are ALWAYS assigned to DB0-DB3, and it seems there is no way to
>> assign them to DB4-DB7 (which in turn are always assigned to control
>> signals).
>>
>> Can you help ?
>>
>> Thanks !
>>
>> ------------------------------------------------------------------------------
>> Put Bad Developers to Shame
>> Dominate Development with Jenkins Continuous Integration
>> Continuously Automate Build, Test & Deployment
>> Start a new project now. Try Jenkins in the cloud.
>> http://p.sf.net/sfu/13600_Cloudbees_APR
>> _______________________________________________
>> Lcd4linux-users mailing list
>> Lcd...@li...
>> https://lists.sourceforge.net/lists/listinfo/lcd4linux-users
>>
>>
>
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