ULP处理器数据如何与主控交互数据的？

[gezhia]

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？



主控代码

Code: Select all

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: %5d\n", (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: %5d\n",(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: %5d\n", (int)pulse_count);
}

ULP代码

Code: Select all

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

[ESP_ICY]

https://docs.espressif.com/projects/esp ... -variables 请查看官方文档的说明，这两个是一样的变量，只不过主程序要用ULP里的变量时前面要加ulp声明

[gezhia]

根据这段文字意思，主控变量measurement count在ULP的头文件里声明成ulp measurement count，就可以在ULP里使用了。这么理解
是否正确?

那是否意味着主控和ULP相互之间是不知道哪个变量是共享的，如果某个共享变量名书写错误，比如主控里M_easurement_count，而ULP里写成了ulp_measurement_count，会导致变量内容无法共享，而编译运行没有任何问题？

例如，ULP RISC-V 程序可以定义 measurement_count 变量，此变量可以定义程序从深度睡眠中唤醒芯片之前需要进行的 ADC 测量的次数。

volatile int measurement_count;

int some_function()
{
//读取测量计数，后续需使用
int temp = measurement_count;

...do something.
}
构建系统生成定义 ULP 编程中全局符号的 ${ULP_APP_NAME}.h 和 ${ULP_APP_NAME}.ld 文件，使主程序能够访问全局 ULP RISC-V 程序变量。上述两个文件包含 ULP RISC-V 程序中定义的所有全局符号，且这些符号均以 ulp_ 开头。

头文件包含对此类符号的声明：

extern uint32_t ulp_measurement_count;

[ESP_ICY]

应该说是 ULP 程序里的变量，在主程序里加上 ulp 前缀后使用