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Re: 3C : LCD I2C
Posted: Fri Aug 01, 2014 2:24 pm
by Dan81
Hello Milek
3.9K is OK. Keep (for now) WDT OFF.
May be, you can test the PCF with some Led and resistor between +5V and Outputs.
Test the file (just flashing led), if it is not OK , may a trouble with the I2C address.
Is it a PCF8574 or PCF8574A, A0 A1 A2 are really connected to gnd ?
Can you take a look with an oscilloscope on lines SCL and SDA ?
Daniel
Re: 3C : LCD I2C
Posted: Tue Aug 05, 2014 3:45 pm
by MilekNS
Dan81 wrote:Hello Milek
3.9K is OK. Keep (for now) WDT OFF.
May be, you can test the PCF with some Led and resistor between +5V and Outputs.
Test the file (just flashing led), if it is not OK , may a trouble with the I2C address.
Is it a PCF8574 or PCF8574A, A0 A1 A2 are really connected to gnd ?
Can you take a look with an oscilloscope on lines SCL and SDA ?
Daniel
Hi Dan
just tested, no leds blinking.
PCF8574T (nxp)
a0,a1,a2 = GND 100%
i have attached my pcb design files, if You have eagle CAD You may take a look but i checked design several times and i don't see any errors.
*note: one jumper is to turn back light ON all the time (ignoring npn transistor and P7 state ) and another one is to connect RW (lcd) to GND ignoring connection with P5 state. that's something i have added as option and it doesn't change anything if not used.
I don't have an oscilloscope
Re: 3C : LCD I2C
Posted: Thu Aug 07, 2014 7:22 pm
by KevinH
I have looked at the schematic and PCB and nothing stands out as an error.
As you don't have a scope I would check the PCF8574T interface writing a simple program to flash the backlight on and off at 1Hz.
That would at least check out the basic ICD and chip.
Re: 3C : LCD I2C
Posted: Thu Aug 07, 2014 9:33 pm
by KevinH
While surfing the forum to understand I2C and FC I came across this post:
http://www.matrixtsl.com/mmforums/viewt ... ave#p61217
It may not be relevant to your specific issue, but as it was interesting for I2C applications and as a good application note link thought I would post it here.
Re: 3C : LCD I2C
Posted: Sun Feb 28, 2016 7:13 pm
by Mouine
Hello,
I tried for a long time to run a 4x20 LCD display with i2c in flowcode v5. I try to redo the above diagram and test but it still doesn't work. Is there a macro to flowcode v5? Could someone help me?
Thank you
Re: 3C : LCD I2C
Posted: Sun Feb 28, 2016 7:25 pm
by Dan81
Hello Mouine
Which flowchart are you using ?
Have you put the pull up on SCL and SDA ?
Can you post a photo of your work?
Daniel
Re: 3C : LCD I2C
Posted: Tue Mar 01, 2016 12:11 pm
by Mouine
Dan81 Hello and thank you for your reply,
I used the following flowchart. I have read and applied all the posts but it does not work.
is there a macro to flowcode V5 ? I used pic18F452.
Thanks