PCF8574 error in SimulIDE

Hi all.

At the beginning, I have started the project with i2c Lcd and find out that i2c connect to Lcd 16x02 or 20x04 through IC PCF8574 has a problem in simulate.

Another thing I have test the same circuit in Proteus and it work as the picture I have include below.

In further, I take the circuit in a real world and it work fine.

The Conclusion is that I think it have a problem with this driver in SimulIDE (1.0.0 and 0.4.15)

Hi.
I will have a look, but without the source code there is not much I can do.

Try with the address 0x57.

arcachofo wrote:Hi.
I will have a look, but without the source code there is not much I can do.

I use Codevision Avr to write the code for driver lcd through PCF8574. As I have mention above, same hex I have uploaded for SimulIDE, Proteus and the same as I upload to my real IC on board.

thanks

Defran wrote:Try with the address 0x57.

it has nothing because in datasheet it takes the address config throughout A0 A1 A3 (range from 20h .. 27h). mine slave PCF8574 is 0x27.

Another thing I used to find out my slaver PCF8574 address is arduino : https://create.arduino.cc/projecthub/abdularbi17/how-to-scan-i2c-address-in-arduino-eaadda -> it is 0x27h

thanks

The problem is that the address in I2CToParallel component is not set correctly.
In your circuit it is set to 80 = 0x50 when it should be 32 = 0x20.

arcachofo wrote:The problem is that the address in I2CToParallel component is not set correctly.
In your circuit it is set to 80 = 0x50 when it should be 32 = 0x20.

I set it 32 as 0x20, nothing done, but if I set to 39 = 0x27, it shows right text on lcd. In datasheet A0 A1 A2 = Vdd Vdd Vdd = 0x27, Vss Vss Vss = 0x20




https://www.nxp.com/docs/en/data-sheet/PCF8574_PCF8574A.pdf

I set it 32 as 0x20, nothing done, but if I set to 39 = 0x27, it shows right text on lcd. In datasheet A0 A1 A2 = Vdd Vdd Vdd = 0x27, Vss Vss Vss = 0x20

In the circuit you sent A0 A1 A2 are connected to +5V.
Setting address to 32 works correctly.

Here you can see that the "hardcoded" address is 0x20, and the first 3 bits are set by A0 A1 A2 pins.
So the correct address is 0x20 = 32.

arcachofo wrote:Here you can see that the "hardcoded" address is 0x20, and the first 3 bits are set by A0 A1 A2 pins.
So the correct address is 0x20 = 32.

in SimulIDE I connected A0, A1, A2 to Ground, it means 32 = 0x20, but take 32 to Control Code in PCF8574 properties, it is not thing done.

You try it in my file SimulIDE that I included.

inclusion, in my code, my slaver address is 0x27 like this:

// I2C LCD Shield initialization for TWI
// PCF8574 I2C bus address: 0x27
// LCD characters/line: 16
lcd_twi_init(0x27, 16);

In proteus, I connect A0 A1 A2 = 0x27 = 39 (connect to 5V+) it work, but if to connect A0 A1 A2 = 0x22 = 32 (connect to ground), it show notthing (because the address now is 0x20).

Use this program to test.

in SimulIDE I connected A0, A1, A2 to Ground, it means 32 = 0x20, but take 32 to Control Code in PCF8574 properties, it is not thing done.

In the circuit you attached (main.sim1.sim1.simu) in your first post you connected A0, A1, A2 to +5V.
Which is the correct thing to do (you did the same in Proteus).
Connecting to ground is wrong if you want to use address 0x27.
If you connect to ground you must use address 0x20 as is clearly shown in the table in your own post.

In conclusion:
To use address 0x27 you must do what is shown in the table in your own post:
- "Control code" = 0x20 = 32
- A0 A1 A2 connected to +5V.

You try it in my file SimulIDE that I included.

I already did and I already told you that it works correctly.

Defran wrote:Use this program to test.

Open file error, I used both 1.0.0 and 0.4.15

arcachofo wrote:

in SimulIDE I connected A0, A1, A2 to Ground, it means 32 = 0x20, but take 32 to Control Code in PCF8574 properties, it is not thing done.

In the circuit you attached (main.sim1.sim1.simu) in your first post you connected A0, A1, A2 to +5V.
Which is the correct thing to do (you did the same in Proteus).
Connecting to ground is wrong if you want to use address 0x27.
If you connect to ground you must use address 0x20 as is clearly shown in the table in your own post.

In conclusion:
To use address 0x27 you must do what is shown in the table in your own post:
- "Control code" = 0x20 = 32
- A0 A1 A2 connected to +5V.

You try it in my file SimulIDE that I included.

I already did and I already told you that it works correctly.

Your "Control Code" reverse to datasheet of PCF85740

Vdd is positive supply 5V
Vss is negative supply or 0v or Ground

In the circuit above you have showed me, A0 A1 A2 you connect to 5V that mean A0 A1 A2 = Vdd Vdd Vdd = 0x27 = 39 (in datasheet). Am i right ? and the question is why you take the "Control Code" is 32 = 0x20 It work, but it must be right if you take 39 = 0x27 like datasheet, but it won't work if you take the "Control code" is 39? (in my code and hex code: it has been programmed to be 0x27 for the address)

in Conclusion, in Proteus, it work like I have mentioned.
Sorry about waste your time but I think it is very weird.



https://www.nxp.com/docs/en/data-sheet/PCF8574_PCF8574A.pdf

In the circuit above you have showed me, A0 A1 A2 you connect to 5V that mean A0 A1 A2 = Vdd Vdd Vdd = 0x27 = 39 (in datasheet).

That is YOUR circuit main.sim1.sim1.simu

and the question is why you take the "Control Code" is 32 = 0x20 It work,

Because that is how it works:
bits 0, 1 and 2 are determined by the state of the pins A0 A1 A2.

but it must be right if you take 39 = 27 like datasheet, but it don't work?

NO, the datasheets shows that you MUST connect A0 A1 A2 to Vdd to use address 0x27.

TEST 0X27 ADDR.

Defran wrote:TEST 0X27 ADDR.

It just like the same result my post above, I can't open your file in 1.0.0 or 0.4.15. but  inspected your code

Code:

#include <Wire.h>
#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x57,16,2);  // ADDRESS HERE

void setup()
{
lcd.init();
lcd.backlight();
lcd.print("Hi everyone!");
}

void loop()
{
 lcd.setCursor(0, 1);
 lcd.print(millis()/1000);
 lcd.print(" Secs");
 delay(100);
}

in datasheet PCF8574 for PCF8574A -> these is no address 0x57

- PCF8574


- PCF8574_A


In real world or proteus it will not work correct. You can try it and show your result right here to me.

thanks

For 0415

Defran wrote:For 0415

Read Table 4. PCF8574 Address Map and view your code with "LiquidCrystal_I2C lcd(0x27,16,2); // ADDRESS HERE" and asking yourself this question: why you code the address in arduino is 0x27 but in the simulate, the address you set for "Control Code" is 32 = 0x20 and it still work fine instead of the same address code 39 = 0x27 as the same of your code in arduino?

Thanks

Read Table 4. PCF8574 Address Map and view your code with "LiquidCrystal_I2C lcd(0x27,16,2); // ADDRESS HERE" and asking yourself this question: why you code the address in arduino is 0x27 but in the simulate, the address you set for "Control Code" is 32 = 0x20 and it still work fine instead of the same address code 39 = 0x27 as the same of your code in arduino?

"Control Code" is not the address, is just the upper part of the address, that is why it is not called "Address" but "Control Code".

The lower 3 bit of the address are determined by the state of pins A0 A1 A2.
So address = Control code (upper 4 bits) + A2 A1 A0