TLV API

通过API通信的TLV API使用以下格式的简单TLV帧。

TLV框架

类型

长度

价值

校验和

第1字节

第二字节

无校验和的有效载荷长度

有效负载字节数从第3位到最大值

SPI上最大252字节
UART上最大255字节

最后一个字节

类型255是保留类型，模块会忽略它。
未知的TLV类型被拒绝。
TLV响应确认每个TLV请求。

校验和算法是CRC8，参考值为 crc8 （多项式构造函数为 x⁸ + x⁵ + x⁴ +1），它将用于计算整个包的校验和。TLV长度不包括此校验和。

代码示例:

C

#include <stdlib.h>
#include "checksum.h"

static uint8_t crc_table[] = {

   0,   49,  98,  83,  196, 245, 166, 151, 185, 136, 219, 234, 125, 76,  31,  46,
   67,  114, 33,  16,  135, 182, 229, 212, 250, 203, 152, 169, 62,  15,  92,  109,
   134, 183, 228, 213, 66,  115, 32,  17,  63,  14,  93,  108, 251, 202, 153, 168,
   197, 244, 167, 150, 1,   48,  99,  82,  124, 77,  30,  47,  184, 137, 218, 235,
   61,  12,  95,  110, 249, 200, 155, 170, 132, 181, 230, 215, 64,  113, 34,  19,
   126, 79,  28,  45,  186, 139, 216, 233, 199, 246, 165, 148, 3,   50,  97,  80,
   187, 138, 217, 232, 127, 78,  29,  44,  2,   51,  96,  81,  198, 247, 164, 149,
   248, 201, 154, 171, 60,  13,  94,  111, 65,  112, 35,  18,  133, 180, 231, 214,
   122, 75,  24,  41,  190, 143, 220, 237, 195, 242, 161, 144, 7,   54,  101, 84,
   57,  8,   91,  106, 253, 204, 159, 174, 128, 177, 226, 211, 68,  117, 38,  23,
   252, 205, 158, 175, 56,  9,   90,  107, 69,  116, 39,  22,  129, 176, 227, 210,
   191, 142, 221, 236, 123, 74,  25,  40,  6,   55,  100, 85,  194, 243, 160, 145,
   71,  118, 37,  20,  131, 178, 225, 208, 254, 207, 156, 173, 58,  11,  88,  105,
   4,   53,  102, 87,  192, 241, 162, 147, 189, 140, 223, 238, 121, 72,  27,  42,
   193, 240, 163, 146, 5,   52,  103, 86,  120, 73,  26,  43,  188, 141, 222, 239,
   130, 179, 224, 209, 70,  119, 36,  21,  59,  10,  89,  104, 255, 206, 157, 172
};

/*
* The function crc_8() calculates the 8 bit wide CRC of an input string of a
* given length.
*/

uint8_t crc_8( const unsigned char *input_str, size_t num_bytes ) {

   size_t a;
   uint8_t crc;
   const unsigned char *ptr;

   crc = CRC_START_8;
   ptr = input_str;

   if ( ptr != NULL ) for (a=0; a<num_bytes; a++) {

      crc = crc_table[(*ptr++) ^ crc];
   }

   return crc;

}

void main(void) {
   uint8_t data[] = {0x01, 0x02, 0x03, 0x04, 0x05};
   uint8_t crc;

   crc = crc_8(data, sizeof(data));
}

Python

crc_table = bytes([
   0,   49,  98,  83,  196, 245, 166, 151, 185, 136, 219, 234, 125, 76,  31,  46,
   67,  114, 33,  16,  135, 182, 229, 212, 250, 203, 152, 169, 62,  15,  92,  109,
   134, 183, 228, 213, 66,  115, 32,  17,  63,  14,  93,  108, 251, 202, 153, 168,
   197, 244, 167, 150, 1,   48,  99,  82,  124, 77,  30,  47,  184, 137, 218, 235,
   61,  12,  95,  110, 249, 200, 155, 170, 132, 181, 230, 215, 64,  113, 34,  19,
   126, 79,  28,  45,  186, 139, 216, 233, 199, 246, 165, 148, 3,   50,  97,  80,
   187, 138, 217, 232, 127, 78,  29,  44,  2,   51,  96,  81,  198, 247, 164, 149,
   248, 201, 154, 171, 60,  13,  94,  111, 65,  112, 35,  18,  133, 180, 231, 214,
   122, 75,  24,  41,  190, 143, 220, 237, 195, 242, 161, 144, 7,   54,  101, 84,
   57,  8,   91,  106, 253, 204, 159, 174, 128, 177, 226, 211, 68,  117, 38,  23,
   252, 205, 158, 175, 56,  9,   90,  107, 69,  116, 39,  22,  129, 176, 227, 210,
   191, 142, 221, 236, 123, 74,  25,  40,  6,   55,  100, 85,  194, 243, 160, 145,
   71,  118, 37,  20,  131, 178, 225, 208, 254, 207, 156, 173, 58,  11,  88,  105,
   4,   53,  102, 87,  192, 241, 162, 147, 189, 140, 223, 238, 121, 72,  27,  42,
   193, 240, 163, 146, 5,   52,  103, 86,  120, 73,  26,  43,  188, 141, 222, 239,
   130, 179, 224, 209, 70,  119, 36,  21,  59,  10,  89,  104, 255, 206, 157, 172
])

def crc_8(input_str):
   crc = 0

   for data in input_str:
      crc = crc_table[data ^ crc]

   return crc

data = []

data.append(0x85)
data.append(0x04)
data.append(0x07)
data.append(0x00)
data.append(0x05)
data.append(0xff)

print (crc_8(data))

C#

byte[] crc_table = new byte[] {
   0,   49,  98,  83,  196, 245, 166, 151, 185, 136, 219, 234, 125, 76,  31,  46,
   67,  114, 33,  16,  135, 182, 229, 212, 250, 203, 152, 169, 62,  15,  92,  109,
   134, 183, 228, 213, 66,  115, 32,  17,  63,  14,  93,  108, 251, 202, 153, 168,
   197, 244, 167, 150, 1,   48,  99,  82,  124, 77,  30,  47,  184, 137, 218, 235,
   61,  12,  95,  110, 249, 200, 155, 170, 132, 181, 230, 215, 64,  113, 34,  19,
   126, 79,  28,  45,  186, 139, 216, 233, 199, 246, 165, 148, 3,   50,  97,  80,
   187, 138, 217, 232, 127, 78,  29,  44,  2,   51,  96,  81,  198, 247, 164, 149,
   248, 201, 154, 171, 60,  13,  94,  111, 65,  112, 35,  18,  133, 180, 231, 214,
   122, 75,  24,  41,  190, 143, 220, 237, 195, 242, 161, 144, 7,   54,  101, 84,
   57,  8,   91,  106, 253, 204, 159, 174, 128, 177, 226, 211, 68,  117, 38,  23,
   252, 205, 158, 175, 56,  9,   90,  107, 69,  116, 39,  22,  129, 176, 227, 210,
   191, 142, 221, 236, 123, 74,  25,  40,  6,   55,  100, 85,  194, 243, 160, 145,
   71,  118, 37,  20,  131, 178, 225, 208, 254, 207, 156, 173, 58,  11,  88,  105,
   4,   53,  102, 87,  192, 241, 162, 147, 189, 140, 223, 238, 121, 72,  27,  42,
   193, 240, 163, 146, 5,   52,  103, 86,  120, 73,  26,  43,  188, 141, 222, 239,
   130, 179, 224, 209, 70,  119, 36,  21,  59,  10,  89,  104, 255, 206, 157, 172
};

public byte crc_8(byte[] data) {

   byte crc = 0;

   foreach (byte b in data) { crc = crc_table[b ^ crc]; }

   return crc;
}

public void calculateChecksum() {

   byte[] data = new byte[6];

   data[0] = 0x85;
   data[1] = 0x04;
   data[2] = 0x07;
   data[3] = 0x00;
   data[4] = 0x5;
   data[5] = 0xff;

   byte crc = crc_8(data);
}

API TLV请求/响应中的CRC示例 leaps_alarm_start

TLV 请求
类型	长度	价值	校验和
0x85	0x04	0x07 0x00 0x05 0xff	0x80

TLV 响应
类型	长度	价值	校验和
0x40	0x01	0x00	0x06

如果配置启用了某些内部事件，则可以在某些接口上生成TLV帧，而无需之前的请求（例如在UART接口或BLE接口上）。CORE_INT GPIO引脚用于通知UART/SPI上的内部事件。

事件可以通过以下方式配置 leaps_int_cfg_set。新事件将设置CORE_INT引脚。在用户在UART或SPI接口上发起任何活动后，CORE_INT引脚会自动清除。多字节数据部分按小字节序排列。