Hi,
I have begin tests with an ESP32 and a MCP23017
And this seem very too slow for my needs on my firsts basics tests on it 
(the display of ONLY one RGB charlieplexed tower of 4x RGB leds that are turned at 90 degrees for each level to the next = 12 monochromatics leds)
Here is the code, I use :
#include <Wire.h>
#include <MCP23017.h>
#define I2C_SDA 21
#define I2C_SCL 22
hw_timer_t *My_timer = NULL;
int seconds = 0;
int frames = 0;
MCP23017 mcp;
void IRAM_ATTR timer_func()
{
seconds++;
Serial.print(seconds);
Serial.print(" seconds (");
Serial.print(frame);
Serial.println(" fps)");
frames=0;
}
void setup_timer()
{
seconds = 0;
My_timer = timerBegin(0, 80, true);
timerAttachInterrupt(My_timer, &timer_func, true);
timerAlarmWrite(My_timer, 1000000, true);
timerAlarmEnable(My_timer); //Just Enable
}
int search_i2c()
{
byte error, address;
int nDevices;
Serial.println("Scanning ...");
nDevices = 0;
for(address = 1; address < 127; address++ )
{
// The i2c_scanner uses the return value of
// the Write.endTransmisstion to see if
// a device did acknowledge to the address.
Wire.beginTransmission(address);
error = Wire.endTransmission();
if (error == 0)
{
Serial.print("I2C device found at address 0x");
if (address<16)
Serial.print("0");
Serial.print(address,HEX);
Serial.println(" :)");
nDevices++;
}
else if (error==4)
{
Serial.print("Unknown error at address 0x");
if (address<16)
Serial.print("0");
Serial.println(address,HEX);
}
}
if (nDevices == 0)
Serial.println("No I2C devices found\n");
else
Serial.println("done\n");
delay(5000); // wait 5 seconds for next scan
return nDevices;
}
void setup_i2c(int sda = I2C_SDA, int scl = I2C_SCL)
{
int found = 0;
Wire.begin();
Serial.println("\nI2C Scanner");
while ( (found = search_i2c() ) == 0 )
{
Serial.println("I2C device not found \n");
delay(5000);
}
}
void mcp_reset()
{
// for ( int i = 0 ; i < 16 ; i++ )
for ( int i = 8 ; i < 12 ; i++ )
{
mcp.pinMode(i, INPUT);
}
}
void setup_mcp()
{
mcp.begin( 7 );
mcp_reset();
}
void mcp_set_pins(int low, int high)
{
mcp.pinMode(low, OUTPUT);
mcp.pinMode(high, OUTPUT);
mcp.digitalWrite(low, LOW);
mcp.digitalWrite(high, HIGH);
// delay(1);
}
void mcp_stage( int pin0, int pin1 )
{
/*
Serial.print("mcp_stage(");
Serial.print(pin0);
Serial.print(",");
Serial.print(pin1);
Serial.println(")");
*/
// mcp.digitalWrite(pin0, LOW);
// mcp.digitalWrite(pin1, HIGH);
mcp_reset();
mcp_set_pins( pin0, pin1);
}
void loop_mcp(int first)
{
int nextpin[4] = { 1, 2, 3, 0};
for ( int i = 0 ; i < 4 ; i++)
{
for ( int j = 0 ; j < 4 ; j++)
{
if( i != nextpin[j] )
{
mcp_stage(i + first, nextpin[j] + first);
}
}
// this seem needed to wait a little if we don't want a regular crash
delay(1);
}
}
void setup()
{
Serial.begin(115200);
setup_i2c();
setup_mcp();
setup_timer();
}
void loop()
{
// search_i2c();
loop_mcp( 8 );
frames++;
}This give me only something between 11 and 12 refresh per second when I need something very more high like 50 or 100 Hz
I find 12 fps with the mcp_reset() call into mcp_stage() and 23 fps without
I find too 23 fps without tje mcp__set_pins(pin0, pin1)
And A VERY BIGGER frequency of refresh at 250 fps without mcp_reset() AND mcp_ set_pins() calls
(and I reset only 4 pins at the mcp_reset() call, not alls pins because in this case the fps is lowered to ONLY 4 fps ...)
It exist another MCP23017 package that is very more speed than the version that I have use from https://www.waveshare.com/wiki ?
(I use the mcp23017.h and . cpp files into the arduino directory of the MCP23017-IO-Expansion-Board-Demo-Code.7z archive)
