请问ULP处理器数据如何与主控交互数据的？

根据官方提供的ULP计数例程里，主控代码里的ulp_edge_count 变量只在主控区域被引用，并没有跟ULP关联。而ULP代码里的计数变量edge_count也是跟主控代码没有任何关联。它们之间到底是如何交互数据的呢？

static void update_pulse_count(void){    const char* namespace = "plusecnt";    const char* count_key = "count";    ESP_ERROR_CHECK( nvs_flash_init() );    nvs_handle_t handle;    ESP_ERROR_CHECK( nvs_open(namespace, NVS_READWRITE, &handle));    uint32_t pulse_count = 0;    esp_err_t err = nvs_get_u32(handle, count_key, &pulse_count);    assert(err == ESP_OK || err == ESP_ERR_NVS_NOT_FOUND);    printf("Read pulse count from NVS: %5dn", (int)pulse_count);    /* ULP program counts signal edges, convert that to the number of pulses */    uint32_t pulse_count_from_ulp = (ulp_edge_count & UINT16_MAX) / 2;    /* In case of an odd number of edges, keep one until next time */    ulp_edge_count = ulp_edge_count % 2;    printf("Pulse count from ULP: %5dn",(int) pulse_count_from_ulp);    /* Save the new pulse count to NVS */    pulse_count += pulse_count_from_ulp;    ESP_ERROR_CHECK(nvs_set_u32(handle, count_key, pulse_count));    ESP_ERROR_CHECK(nvs_commit(handle));    nvs_close(handle);    printf("Wrote updated pulse count to NVS: %5dn", (int)pulse_count);}

edge_detected:        /* Reset debounce_counter to debounce_max_count */        move r3, debounce_max_count        move r2, debounce_counter        ld r3, r3, 0        st r3, r2, 0        /* Flip next_edge */        move r3, next_edge        ld r2, r3, 0        add r2, r2, 1        and r2, r2, 1        st r2, r3, 0        /* Increment edge_count */        move r3, edge_count        ld r2, r3, 0        add r2, r2, 1        st r2, r3, 0        /* Compare edge_count to edge_count_to_wake_up */        move r3, edge_count_to_wake_up        ld r3, r3, 0        sub r3, r3, r2        jump wake_up, eq        /* Not yet. End program */        halt