Hi to all,
I am not sure, if this is the correct forum for my question, so please move it if necessary.
I need to change the I2C pins. I use a color TFT display (https://www.az-delivery.de/products/2-4-tft-lcd-touch-display), which uses the standard SDA pin (A4) for LCD_RST. I could swap to Arduino Mega, but this board is too large (and uses too much current), I want to realize my project on an Arduino Mini Pro.
I found that there are some "bit banging" libraries which replace the Wire library, so BitBang_I2C (https://raw.githubusercontent.com/bitbank2/BitBang_I2C/master/examples/I2C_Detector/I2C_Detector.ino)
I used the following code to test the library and the device. (Hardware: AS7262 Breakout Board, SDA connected with D10, SCL connected with D11 of an Mini Pro 328, 5V)
When running the program I got an "0 device(s) found", when disconnecting the Breakout Board I got "I2C pins are not correct or the bus is being pulled low by a bad device; unable to run scan"
Can you help me to find out what was wrong?
//
// I2C Detector - scan and identify devices on an I2C bus using the BitBang_I2C library
//
// The purpose of this code is to provide a sample sketch which can serve
// to detect not only the addresses of I2C devices, but what type of device each one is.
// So far, I've added the 25 devices I've personally used or found to be reliably detected
// based on their register contents. I encourage people to do pull requests to add support
// for more devices to make this code have wider appeal.
// There are plenty of I2C devices which appear at fixed addresses, yet don't have unique
// "Who_Am_I" registers or other data to reliably identify them. It's certainly possible to
// write code which initializes these devices and tries to verify their identity. This can
// potentially damage them and would necessarily increase the code size. I would like to keep
// the size of this code small enough so that it can be included in many microcontroller
// projects where code space is scarce.
// Copyright (c) 2019 BitBank Software, Inc.
// Written by Larry Bank
// email: bitbank@pobox.com
// Project started 25/02/2019
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
//
// Uses my Bit Bang I2C library. You can find it here:
// https://github.com/bitbank2/BitBang_I2C
#include <BitBang_I2C.h>
#define SDA_PIN 10
#define SCL_PIN 11
//
// If you don't need the explicit device names displayed, disable this code by
// commenting out the next line
//
//#define SHOW_NAME
#ifdef SHOW_NAME
const char *szNames[] = {"Unknown","SSD1306","SH1106","VL53L0X","BMP180", "BMP280","BME280",
"MPU-60x0", "MPU-9250", "MCP9808","LSM6DS3", "ADXL345", "ADS1115","MAX44009",
"MAG3110", "CCS811", "HTS221", "LPS25H", "LSM9DS1","LM8330", "DS3231", "LIS3DH",
"LIS3DSH","INA219","SHT3X","HDC1080","MPU6886","BME680", "AXP202", "AXP192", "24AA02XEXX",
"DS1307", "MPU688X", "FT6236G", "FT6336G", "FT6336U", "FT6436", "BM8563","BNO055"};
#endif
BBI2C bbi2c;
void setup() {
Serial.begin(115200);
memset(&bbi2c, 0, sizeof(bbi2c));
bbi2c.bWire = 0; // use bit bang, not wire library
bbi2c.iSDA = SDA_PIN;
bbi2c.iSCL = SCL_PIN;
I2CInit(&bbi2c, 100000L);
delay(100); // allow devices to power up
}
void loop() {
uint8_t map[16];
uint8_t i;
int iDevice, iCount;
Serial.println("Starting I2C Scan");
I2CScan(&bbi2c, map); // get bitmap of connected I2C devices
if (map[0] == 0xfe) // something is wrong with the I2C bus
{
Serial.println("I2C pins are not correct or the bus is being pulled low by a bad device; unable to run scan");
}
else
{
iCount = 0;
for (i=1; i<128; i++) // skip address 0 (general call address) since more than 1 device can respond
{
if (map[i>>3] & (1 << (i & 7))) // device found
{
iCount++;
Serial.print("Device found at 0x");
Serial.print(i, HEX);
iDevice = I2CDiscoverDevice(&bbi2c, i);
Serial.print(", type = ");
#ifdef SHOW_NAME
Serial.println(szNames[iDevice]); // show the device name as a string
#else
Serial.println(iDevice); // show the device name as the enum index
#endif
}
} // for i
Serial.print(iCount, DEC);
Serial.println(" device(s) found");
}
delay(5000);
}
Thank you,
-richard
