PCF8575 ESP32 DigitalWrite Not working on sec I2C

Projects Programming
1

I have the digitalread on all pins working on my esp32, I followed the example but is not working. When I measure the pin to ground it stays low on digitalwrite. (the chip is not fried, I have multiple chip with all the same issue).

This is the expansion board I am using
2022-01-24_004035

I have solderd vcc to vdd (for not using the voltage regulator)
2022-01-24_004205

In the library I did

#define NOT_SEQUENTIAL_PINOUT

#include <PCF8575.h>
#include <Wire.h>

TwoWire I2Cone = TwoWire(0);
//TwoWire I2Ctwo = TwoWire(1);
PCF8575 PCF(&I2Cone, 0x20, 16,17);

void setup() {
	Serial.begin(115200);
	while (!Serial);
	//PCF.pinMode(P00, INPUT);

	I2Cone.begin(16, 17, 400000); // SDA pin 16, SCL pin 17, 400kHz frequency

	for (int i = 0; i < 8; i++) {
		PCF.pinMode(i, OUTPUT);
	}
	
	//PCF.begin(16, 17);

	PCF.begin();

	write();
}
void loop() {
	delay(1000);
	//read();
}
void read() {
	Serial.print("val: ");
	Serial.println(PCF.digitalRead(P00));
}
void write() {
	//PCF.digitalWrite(P07, HIGH);

	for (int i = 0; i < 8; i++) {
		PCF.digitalWrite(i, HIGH);
	}
}
2

Here is my log

Opening port
Port open
�Set pin 0 as 2
writeMode: 1readMode: 0
Write mode: 1
Set pin 1 as 2
writeMode: 11readMode: 0
Write mode: 11
Set pin 2 as 2
writeMode: 111readMode: 0
Write mode: 111
Set pin 3 as 2
writeMode: 1111readMode: 0
Write mode: 1111
Set pin 4 as 2
writeMode: 11111readMode: 0
Write mode: 11111
Set pin 5 as 2
writeMode: 111111readMode: 0
Write mode: 111111
Set pin 6 as 2
writeMode: 1111111readMode: 0
Write mode: 1111111
Set pin 7 as 2
writeMode: 11111111readMode: 0
Write mode: 11111111
Set write mode
usedPin pin 11111111111111111111111100000000
Start end trasmission if stop here check pullup resistor.
Begin trasmission
Write data 1 for pin 0 bin value 1 value 1
--> 1
1
0
Start end trasmission if stop here check pullup resistor.
Begin trasmission
Write data 11 for pin 1 bin value 10 value 1
--> 3
3
0
Start end trasmission if stop here check pullup resistor.
Begin trasmission
Write data 111 for pin 2 bin value 100 value 1
--> 7
7
0
Start end trasmission if stop here check pullup resistor.
Begin trasmission
Write data 1111 for pin 3 bin value 1000 value 1
--> 15
15
0
Start end trasmission if stop here check pullup resistor.
Begin trasmission
Write data 11111 for pin 4 bin value 10000 value 1
--> 31
31
0
Start end trasmission if stop here check pullup resistor.
Begin trasmission
Write data 111111 for pin 5 bin value 100000 value 1
--> 63
63
0
Start end trasmission if stop here check pullup resistor.
Begin trasmission
Write data 1111111 for pin 6 bin value 1000000 value 1
--> 127
127
0
Start end trasmission if stop here check pullup resistor.
Begin trasmission
Write data 11111111 for pin 7 bin value 10000000 value 1
--> 255
255
0
Start end trasmission if stop here check pullup resistor.

3

The ESP32's Arduino core defines the I2C pins as GPIO_NUM_22, SCL, and GPIO_NUM_21, SDA, why not use those pins? You can program the ESP32's pin matrix to set the I2C pins as GPIO_NUM_17/16, which are natural serial port pins. Here is a link to the ESP32's docs where you can read about how to redefine the ESP32's pin matrix to change the I2C GPIO pins.

4

I just change the pins to the defaults, still having the same issue.

PCF8575 PCF(0x20)

And left out wire.begin()

5

Could it be I need to solder the a1,a2 and a3 solderpads to ground? All tutorials tell me an if I want to change the adress. Maybe its a must?

I will try and rescan it, let you know if it works...

6

The address stays the same

Scanning...
I2C device found at address 0x20 !
done

Nothing changed... still low

7

Digitalread still works.

I have two 4.7k resistors as pullup. Maybe they are to weak... Can somebody tell me what the right value of pullup resistors?

8

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