Stepper over MCP23017

[Juan1ll0]

Hi friends,
I'm working with a Nema17 connected to an L298N and this to a MC23017. I wrote a basic adaptor for MCP23017 to pass as DigitalWriter to Stepper driver. The code is like this:

package mcpDigitalWriter

import (
	"fmt"
	"slices"
	"strconv"

	"gobot.io/x/gobot/v2/drivers/i2c"
)

type MCPDigitalWriter struct {
	name      string
	MCPDevice *i2c.MCP23017Driver
}

func NewMCPDigitalWriter(mcp *i2c.MCP23017Driver) *MCPDigitalWriter {
	return &MCPDigitalWriter{
		name:      "default",
		MCPDevice: mcp,
	}
}

func (mcp *MCPDigitalWriter) DigitalWrite(pin string, level byte) error {
	if slices.Contains([]string{"0", "1", "2", "3", "4", "5", "6", "7"}, pin) {
		intPin, _ := strconv.Atoi(pin)
		mcp.MCPDevice.WriteGPIO(uint8(intPin), "A", level)
		return nil
	}

	if slices.Contains([]string{"8", "9", "10", "11", "12", "13", "14", "15"}, pin) {
		intPin, _ := strconv.Atoi(pin)
		intPin = intPin - 8
		mcp.MCPDevice.WriteGPIO(uint8(intPin), "B", level)
		return nil
	}

	return fmt.Errorf("not a valid pin number")
}

func (mcp *MCPDigitalWriter) Connect() error {
	return nil
}

func (mcp *MCPDigitalWriter) Finalize() error {
	return nil
}

func (mcp *MCPDigitalWriter) Name() string {
	return mcp.name
}

func (mcp *MCPDigitalWriter) SetName(n string) {
	mcp.name = n
}

And in main function:

....
r := raspi.NewAdaptor()
bus := 1

mux2 := i2c.NewMCP23017Driver(r, i2c.WithBus(bus), i2c.WithAddress(0x21))
mcpDigitalWriter := mcpDigitalWriter.NewMCPDigitalWriter(mux2)

countRot := 10
stepPerRevision := int(360.0 / 1.875)

stepper := gpio.NewStepperDriver(mcpDigitalWriter,
	[4]string{"0", "1", "2", "3"},
	gpio.StepperModes.DualPhaseStepping,
	uint(stepPerRevision),
)
.....

It works, but I notice that doesn't work as fine as if I connect L298N with stepper directly to Raspberry Pi, makes more noise, less torque and speed. I try changing pins but same result. Does anyone what is happening?. Is something wrong?

Thank you very much.