Hands-On: Flash & EEPROM Access

/* NvM block access: read and write via AUTOSAR NvM API */
#include "NvM.h"

/* NvM block IDs (generated by AUTOSAR configurator) */
#define NVM_BLOCK_ODOMETER    ((NvM_BlockIdType)2u)
#define NVM_BLOCK_CALIB       ((NvM_BlockIdType)5u)

/* RAM mirrors: NvM copies NV data here on read; writes from here */
static uint32 g_odometer_km = 0u;   /* RAM mirror for odometer */
static uint8  g_calib[512];          /* RAM mirror for calibration */

/* --- Read at startup (called from EcuM_AL_DriverInitTwo) --- */
void NvM_ReadAll_AndWait(void)
{
    NvM_ReadAll();  /* triggers async read of all NvM blocks */

    /* Wait for all reads to complete (startup phase only) */
    /* In production: use NvM status polling in startup sequence */
    uint16 timeout = 10000u;  /* 10s max */
    while ((NvM_GetErrorStatus(NVM_BLOCK_ODOMETER, ...) == NVM_REQ_PENDING)
           && (timeout-- > 0u)) {
        NvM_MainFunction();
        Fls_MainFunction();
        Eep_MainFunction();
        /* 1ms delay */
    }
}

/* --- Write (triggered by application) --- */
void App_UpdateOdometer(uint32 new_km)
{
    g_odometer_km = new_km;
    /* Request NvM write (async: Fee/EEP will handle at next opportunity) */
    NvM_WriteBlock(NVM_BLOCK_ODOMETER, &g_odometer_km);
    /* NvM_WriteAll() called at shutdown (EcuM GoSleep) to flush pending writes */
}

/* Power-loss safe odometer: write with CRC protection */
/* NvM handles CRC automatically when NvMBlockUseCrc = TRUE */
/* On read after power loss during write: NvM detects CRC mismatch,
   restores from redundant block (NvM_BlockManagementType = REDUNDANT) */

#define ODOMETER_MAX_KM  999999u

typedef struct {
    uint32 km_total;      /* total odometer */
    uint32 km_trip;       /* trip counter */
    uint16 write_count;   /* NVM write cycle counter (wear monitor) */
    uint8  reserved[2];
} OdometerBlock_t;

static OdometerBlock_t g_odometer;  /* NvM RAM mirror */

void Odometer_Update_1min(uint32 distance_m)
{
    if (g_odometer.km_total >= ODOMETER_MAX_KM) return;

    g_odometer.km_total  += distance_m / 1000u;
    g_odometer.km_trip   += distance_m / 1000u;
    g_odometer.write_count++;

    /* NvM write request: NvM writes at shutdown or on periodic flush */
    NvM_SetDataIndex(NVM_BLOCK_ODOMETER, 0u);  /* select dataset 0 */
    NvM_WriteBlock(NVM_BLOCK_ODOMETER, &g_odometer);
    /* NvM_BlockManagementType = REDUNDANT: two physical copies written */
    /* If power fails during write, second copy is used on next startup */
}