I2C PicKit Serial Demo Board Application

Location: ClaudeWork/PicKitI2CSerialDemoBdW

Supported Platforms: MODM7AE70 SBE70LC SOMRT1061 MOD5441X NANO54415

Overview

This application demonstrates the use of the Microchip PicKit Serial I2C Demo Board with NetBurner embedded systems using the Wire API. The demo showcases communication with five different I2C peripheral devices through both a serial menu interface and a web-based documentation page.

API

This application uses the NetBurner Wire API for I2C communication:

TwoWire Wire - Global I2C bus instance
Wire.begin() - Initialize I2C peripheral (handles pin configuration automatically)
TwoWireObject - Device wrapper for register read/write operations

Supported Platforms

MODM7AE70 - SAME70 based module
SBE70LC - SAME70 based single board computer
SOMRT1061 - i.MX RT1061 based module
MOD5441X - MCF5441X ColdFire based module
NANO54415 - MCF54415 ColdFire based module

I2C Peripherals Demonstrated

The application interfaces with the following Microchip I2C devices:

24LC0B EEPROM - 2Kbit (256 x 8) memory storage
MCP9800 - Digital temperature sensor with 12-bit resolution
MCP23008 - GPIO port expander connected to LEDs
TC1321 - 10-bit Digital-to-Analog Converter (DAC) with 2.5V reference
MCP3221 - 12-bit Analog-to-Digital Converter (ADC)

Features

Web Interface

Access the built-in web page at http://<device-ip>/ for:

I2C device table with addresses and descriptions
Serial console command reference
Hardware connection guide
Troubleshooting information

Interactive Serial Menu

The application provides a serial console menu with the following options:

1 - Erase EEPROM (fill with 0x00)
2 - Read EEPROM and display contents in hex format
3 - Write incrementing sequence to EEPROM (0x00, 0x01, 0x02...)
A - Read ADC voltage value
D - DAC test (prompts for value 0-1023)
T - Read temperature sensor

Automatic LED Sequence

The application continuously cycles through the LEDs connected to the MCP23008 GPIO expander, providing visual feedback that the system is running.

Temperature Sensor Configuration

The MCP9800 temperature sensor is automatically configured for 12-bit resolution on first use, providing temperature readings in both Celsius and Fahrenheit.

I2C Configuration

Bus Speed: Default Wire API speed
Address Format: 7-bit addresses (NetBurner standard)
Pin Configuration: Handled automatically by Wire.begin()

Hardware Pin Connections

MODM7AE70 (P2 Header)

Signal	Header Pin	Function
SDA	P2[39]	TWD0 - I2C Data
SCL	P2[42]	TWCK0 - I2C Clock

SBE70LC (J1 Header)

Signal	Header Pin	Function
SDA	J1[16]	TWD0 - I2C Data
SCL	J1[17]	TWCK0 - I2C Clock

SOMRT1061 (Module Pins)

Signal	Module Pin	Function
SDA	Pin 41	LPI2C1_SDA - I2C Data
SCL	Pin 40	LPI2C1_SCL - I2C Clock

MOD5441X (J2 Header)

Signal	Header Pin	Function
SDA	J2[39]	I2C0_SDA - I2C Data
SCL	J2[42]	I2C0_SCL - I2C Clock

NANO54415 (Module Pins)

Signal	Module Pin	Function
SDA	Pin 29	I2C0_SDA - I2C Data
SCL	Pin 27	I2C0_SCL - I2C Clock

Also connect GND and 3.3V to power the PicKit board.

I2C Pull-up Resistors

The PicKit Serial I2C Demo Board includes onboard pull-up resistors, so no external pull-ups are required.

Typical I2C pull-up resistor values for reference:

Bus Speed	Resistor Value	Notes
Standard (100 kHz)	4.7k	Most common
Fast (400 kHz)	2.2k - 4.7k	Lower values for faster rise times
Fast+ (1 MHz)	1k - 2.2k	Needed for high-speed operation

Note:** Adding too many pull-ups in parallel can cause signal issues. The NetBurner dev boards may also have internal or onboard pull-ups.

I2C Address Mapping

The application handles the conversion from Microchip's 8-bit address format (including R/W bit) to NetBurner's 7-bit format:

Device          8-bit Address    7-bit Address
24LC0B EEPROM   0xA0            0x50
MCP9800 Temp    0x92            0x49
MCP23008 GPIO   0x40            0x20
TC1321 DAC      0x90            0x48
MCP3221 ADC     0x9A            0x4D

Key Functions

EEPROM Operations

EepromWriteBuf() - Writes data with automatic page boundary handling (8-byte pages)
EepromRead() - Reads data from EEPROM
WaitForEepromWriteCmpl() - Polls EEPROM for write completion

Sensor Reading

ReadTempSensor() - Configures and reads MCP9800 temperature sensor
ReadADC() - Reads 12-bit ADC value and converts to voltage
WriteDAC() - Writes 10-bit value to DAC with user input

LED Control

WriteLeds() - Controls LEDs via MCP23008 GPIO expander
IncrementLEDs() - Automatic LED sequencing

Technical Details

Wire API Status Codes

The application includes I2C status checking with descriptive error messages:

wire_success (0) - Operation successful
wire_data_too_big (1) - Data too large for buffer
wire_NACK_on_address (2) - Device not responding
wire_NACK_on_data (3) - Device rejected data
wire_other_error (4) - Other error
wire_timeout (5) - Operation timed out

Data Conversion

Temperature readings are converted from 2's complement format to floating-point
ADC values are converted to voltage (3.3V reference, 12-bit resolution)
DAC values support 0-2.5V output range (10-bit resolution)

Address Conflict Warning

Many NetBurner development boards include a Real Time Clock (RTC) at I2C address 0x51 (0xA2). This conflicts with the PicKit EEPROM address range. When the PicKit board is connected, the onboard RTC will not function correctly.

Usage Instructions

Connect the Microchip PicKit Serial I2C Demo Board to your NetBurner development board's I2C pins (SDA, SCL, GND, 3.3V)
Compile and load the application onto your target platform
Access the web interface at http://<device-ip>/ for documentation
Connect to the serial console (typically 115200 baud)
Use the interactive menu to test different I2C peripherals
Observe the LED sequence to verify system operation

Troubleshooting

If you see "LED GPIO Expander error - check if PicKit board is connected":

Verify the PicKit board is properly connected
Check I2C pull-up resistors are present
Ensure correct voltage levels (3.3V)

Requirements

NetBurner development tools and runtime system
Microchip PicKit Serial I2C Demo Board
Compatible NetBurner hardware platform (MODM7AE70 or SBE70LC)

Project Structure

PicKitI2CSerialDemoBdW/
├── src/
│   ├── main.cpp      - Main application code
│   └── htmldata.cpp  - Auto-generated web content
├── html/
│   ├── index.html    - Web documentation page
│   └── logo.png      - NetBurner logo
├── makefile          - Build configuration
└── ReadMe.txt        - This file