How to use Infineon's TLE9877 chip to achieve EEPROM data storage function

 The Infineon TLE9877 is a highly integrated automotive-grade motor control IC with an embedded ARM® Cortex®-M3 core, FLASH memory, and peripherals like ADCs, PWMs, and communication interfaces. While the TLE9877 does not have dedicated EEPROM memory, data storage functionality can be achieved using its internal Flash memory.

You can simulate EEPROM-like behavior using a portion of the Flash memory designated for data retention. This method is often referred to as EEPROM emulation and is common in microcontrollers that lack dedicated EEPROM.

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Steps to Achieve EEPROM Functionality on TLE9877

1. Overview of Flash Memory

The TLE9877 contains 128 KB of Flash memory, which is primarily used to store code. However, a portion of this Flash memory can be reserved for data storage. Key features:

• Flash memory is non-volatile, meaning data persists after power loss.
• It supports page-based erase operations (erase before write).
• Flash endurance is typically 10,000 cycles, so it’s less durable than true EEPROM.

2. Key Concepts for EEPROM Emulation

To emulate EEPROM:

• Use one or more Flash pages to store data.
• Organize the Flash pages into "active" and "backup" pages for wear leveling.
• Implement mechanisms to manage writes and erases efficiently.

Flash Memory Structure:

• Sector Size: The Flash in the TLE9877 is organized into sectors, with the smallest erasable unit being a Flash page (2 KB in size).
• Writing to Flash memory requires:
  1. Erasing the page.
  2. Writing new data to the erased page.

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3. Reserve Flash Memory for Data Storage

1. Decide on the Storage Size: Determine the amount of Flash memory you want to reserve for "EEPROM" data.
2. Reserve Flash Pages:
   • Ensure the reserved Flash area does not overlap with the program code.
   • Adjust the linker script or memory map accordingly.

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4. Implement EEPROM Emulation

Below is a step-by-step process to achieve EEPROM functionality:

Step 1: Erase a Flash Page

Flash memory must be erased before new data can be written. Erase operations set all bits to 1.

c

#include "tle_device.h"

#define EEPROM_START_ADDRESS  0x0801F800U // Example: Last page of Flash memory (modify accordingly)

// Function to erase a Flash page
void Flash_ErasePage(uint32_t address) {
    // Enable Flash for programming
    FLASH->FPR = 0x5AA5; // Unlock Flash write access
    FLASH->FSR = 0x0001; // Select Page Erase operation

    *(volatile uint32_t *)address = 0x00000000U; // Dummy write to trigger erase

    while (FLASH->FSR & FLASH_FSR_BSY) {
        // Wait until Flash operation is complete
    }

    FLASH->FPR = 0x0000; // Lock Flash programming
}

Step 2: Write Data to Flash

Write data word-by-word (32-bit words) into the erased Flash page.

c

// Function to write a 32-bit word to Flash
void Flash_WriteWord(uint32_t address, uint32_t data) {
    FLASH->FPR = 0x5AA5; // Unlock Flash write access
    FLASH->FSR = 0x0000; // Select standard program operation

    *(volatile uint32_t *)address = data; // Write data

    while (FLASH->FSR & FLASH_FSR_BSY) {
        // Wait until Flash operation is complete
    }

    FLASH->FPR = 0x0000; // Lock Flash programming
}

Step 3: Read Data from Flash

Reading from Flash memory is straightforward, as it behaves like normal memory.

c

// Function to read a 32-bit word from Flash
uint32_t Flash_ReadWord(uint32_t address) {
    return *(volatile uint32_t *)address;
}

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5. Store and Update Data

To simulate EEPROM functionality:

1. Erase a Flash page.
2. Write your data sequentially (like a log).
3. Use the latest valid data entry during read operations.

Example: Writing and Reading Data

c

#define EEPROM_DATA_ADDRESS EEPROM_START_ADDRESS

void Write_EEPROM_Data(uint32_t data) {
    Flash_ErasePage(EEPROM_DATA_ADDRESS); // Erase the page
    Flash_WriteWord(EEPROM_DATA_ADDRESS, data); // Write new data
}

uint32_t Read_EEPROM_Data(void) {
    return Flash_ReadWord(EEPROM_DATA_ADDRESS); // Read data
}

int main(void) {
    uint32_t stored_data;

    // Write example data
    Write_EEPROM_Data(0x12345678);

    // Read back the data
    stored_data = Read_EEPROM_Data();

    while (1) {
        // Keep looping (check stored_data in debugger)
    }
}

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6. Enhance with Wear Leveling (Optional)

To improve Flash longevity:

• Divide the reserved Flash pages into multiple blocks.
• Rotate writes among blocks to distribute the erase/write cycles evenly.

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7. Precautions

1. Endurance: Flash memory has a limited number of erase/write cycles (e.g., 10,000 cycles). Use wear leveling for frequent writes.
2. Power Loss: If power is lost during an erase/write operation, data corruption can occur. Implement checksums or redundancy to ensure data integrity.
3. Alignment: Flash writes typically require word (32-bit) alignment.

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8. Tools and Debugging

• Use Infineon’s Config Wizard and DAVE IDE for development.
• Verify the Flash memory contents using a debugger or programming tools like MemTool.
• Simulate Flash writes in software to ensure correctness before deployment.

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Conclusion

To achieve EEPROM-like data storage using the Infineon TLE9877:

1. Reserve Flash memory pages for data storage.
2. Implement erase, write, and read functions for Flash memory.
3. Use techniques like wear leveling to increase the lifespan of the Flash memory.

This approach emulates EEPROM functionality and provides non-volatile data retention while leveraging the existing Flash memory.