Search found 8 matches

by Paul van de Veen
Sat Jan 06, 2018 7:35 pm
Forum: Interface
Topic: PCF8574 I2C to 8-bit digital port expander (HCMODU0120)
Replies: 15
Views: 3516

Re: PCF8574 I2C to 8-bit digital port expander (HCMODU0120)

I attached a 4x3 keypad to this Port Expander. Works nice with the standard i2ckeypad.h library I also attached an LCD with I2C Backpack SHield. In this way an I2C keypad is achieved. But.... if I have NO LCD attached, this fails after a couple of keypresses. It seems that the I2C bus is messed up. ...
by Paul van de Veen
Mon Nov 27, 2017 3:54 pm
Forum: Interface
Topic: PCF8574 I2C to 8-bit digital port expander (HCMODU0120)
Replies: 15
Views: 3516

Re: PCF8574 I2C to 8-bit digital port expander (HCMODU0120)

Hi Andrew, Many thanks. Now it works as a charm. I and my friends completely overlooked that Mode is a Boolean, not a byte, so the bit manipulation in the previous .cpp were not allowed. A small but important difference. (It would be great if the Arduino compiler would have complained..) My sincere ...
by Paul van de Veen
Sun Nov 26, 2017 2:23 pm
Forum: Interface
Topic: PCF8574 I2C to 8-bit digital port expander (HCMODU0120)
Replies: 15
Views: 3516

Re: PCF8574 I2C to 8-bit digital port expander (HCMODU0120)

Would be great if this issue can be solved. I too checked the library and neither do I see any explanation why the order makes any difference. Of course knowing the issue is also the way to get around. But I included this Port Expander in a course for my students. And it is difficult to explain to t...
by Paul van de Veen
Sat Nov 25, 2017 6:23 pm
Forum: Interface
Topic: PCF8574 I2C to 8-bit digital port expander (HCMODU0120)
Replies: 15
Views: 3516

Re: PCF8574 I2C to 8-bit digital port expander (HCMODU0120)

I am just blinking two leds as a demonstration of this phenomenon. My code: My code: #include "HCPCF8574.h" //Include the HCPCF8574 library byte I2C_ADD = 0x20; //I2C address of the PCF8574 HCPCF8574 Port(I2C_ADD); //Create an instance of the library int PortLedpinA = 0; int PortLedpinB = 1; void se...
by Paul van de Veen
Sat Nov 25, 2017 11:24 am
Forum: Interface
Topic: PCF8574 I2C to 8-bit digital port expander (HCMODU0120)
Replies: 15
Views: 3516

Re: PCF8574 I2C to 8-bit digital port expander (HCMODU0120)

Hi all, I have a problem with the PCF8574 port expander I can not explain. 2 led's are connected by means of 330Ohm resistor to Vcc and to pin0 and pin1. They are supposed to blink simultaneously. The code is of maximum simplicity. When I define the Port.pinMode in increasing order it works. Port.pi...
by Paul van de Veen
Tue Oct 31, 2017 6:12 pm
Forum: Interface
Topic: PCF8574 I2C to 8-bit digital port expander (HCMODU0120)
Replies: 15
Views: 3516

Re: PCF8574 I2C to 8-bit digital port expander (HCMODU0120)

I received 3 of these and tested them, there Hex Address start at 0x20 for the current devices which are PCF8574T. if the chip is PCF8574A the start Address is 0x38 the Sketch will need to be altered accordingly. I.E #define I2C_ADD 0x20 I can't find the library. Could you post a working link pleas...
by Paul van de Veen
Tue Oct 31, 2017 6:08 pm
Forum: Arduino
Topic: HCPCF8574 - Library for PCF8574 8 bit port expander
Replies: 2
Views: 2051

Re: HCPCF8574 - Library for PCF8574 8 bit port expander

The link to the HCPCF8574 library is broken.
Can anyone provide me with this library?

Thanks in advance!
Paul