LMT86LP模拟温度传感器

介绍

LMT86是精密的CMOS温度传感器，它的大致参数如下：

精度：±0.4误差
范围：0°C 至 150°C
封装：TO-92S
引脚：VDD、GND、OUT
价格：4RMB
厂商：德州仪器
供电：2.2V 至 5.5V

模块外观大概长这么样

硬件

VDD、GND、OUT引脚连线参考，电源端（VDD）加去耦电容、输出端（OUT）加滤波电容

连接ADC采集模拟量

关系表

温度和VOUT的对应关系

温度(°C)	VOUT(mV)	温度(°C)	VOUT(mV)	温度(°C)	VOUT(mV)	温度(°C)	VOUT(mV)	温度(°C)	VOUT(mV)
-50	2616	-10	2207	30	1777	70	1335	110	883
-49	2607	-9	2197	31	1766	71	1324	111	872
-48	2598	-8	2186	32	1756	72	1313	112	860
-47	2589	-7	2175	33	1745	73	1301	113	849
-46	2580	-6	2164	34	1734	74	1290	114	837
-45	2571	-5	2154	35	1723	75	1279	115	826
-44	2562	-4	2143	36	1712	76	1268	116	814
-43	2553	-3	2132	37	1701	77	1257	117	803
-42	2543	-2	2122	38	1690	78	1245	118	791
-41	2533	-1	2111	39	1679	79	1234	119	780
-40	2522	0	2100	40	1668	80	1223	120	769
-39	2512	1	2089	41	1657	81	1212	121	757
-38	2501	2	2079	42	1646	82	1201	122	745
-37	2491	3	2068	43	1635	83	1189	123	734
-36	2481	4	2057	44	1624	84	1178	124	722
-35	2470	5	2047	45	1613	85	1167	125	711
-34	2460	6	2036	46	1602	86	1155	126	699
-33	2449	7	2025	47	1591	87	1144	127	688
-32	2439	8	2014	48	1580	88	1133	128	676
-31	2429	9	2004	49	1569	89	1122	129	665
-30	2418	10	1993	50	1558	90	1110	130	653
-29	2408	11	1982	51	1547	91	1099	131	642
-28	2397	12	1971	52	1536	92	1088	132	630
-27	2387	13	1961	53	1525	93	1076	133	618
-26	2376	14	1950	54	1514	94	1065	134	607
-25	2366	15	1939	55	1503	95	1054	135	595
-24	2355	16	1928	56	1492	96	1042	136	584
-23	2345	17	1918	57	1481	97	1031	137	572
-22	2334	18	1907	58	1470	98	1020	138	560
-21	2324	19	1896	59	1459	99	1008	139	549
-20	2313	20	1885	60	1448	100	997	140	537
-19	2302	21	1874	61	1436	101	986	141	525
-18	2292	22	1864	62	1425	102	974	142	514
-17	2281	23	1853	63	1414	103	963	143	502
-16	2271	24	1842	64	1403	104	951	144	490
-15	2260	25	1831	65	1391	105	940	145	479
-14	2250	26	1820	66	1380	106	929	146	467
-13	2239	27	1810	67	1369	107	917	147	455
-12	2228	28	1799	68	1358	108	906	148	443
-11	2218	29	1788	69	1346	109	895	149	432

驱动

ADC配置：初始化ADC2用于温度传感器读取

void InitAdc2(void)
{
    extern void DSP28x_usDelay(Uint32 Count);

    // To powerup the ADC2 the ADC2ENCLK bit should be set first to enable
    // clocks, followed by powering up the bandgap, reference circuitry, and
    // ADC2 core.
    // Before the first conversion is performed a 5ms delay must be observed
    // after power up to give all analog circuits time to power up and settle

    // Please note that for the delay function below to operate correctly the
    // CPU_RATE define statement in the F28M35x_Examples.h file must
    // contain the correct CPU clock period in nanoseconds.
    EALLOW;
    Adc2Regs.ADCCTL1.bit.ADCBGPWD  = 1;      // Power ADC2 BG
    Adc2Regs.ADCCTL1.bit.ADCREFPWD = 1;      // Power reference
    Adc2Regs.ADCCTL1.bit.ADCPWDN   = 1;      // Power ADC2
    Adc2Regs.ADCCTL1.bit.ADCENABLE = 1;      // Enable ADC2
    Adc2Regs.ADCCTL1.bit.ADCREFSEL = 0;      // Select interal BG
    EDIS;

    DELAY_US(ADC_usDELAY);         // Delay before converting ADC2 channels
}

void TempSensor_Init(void)
{
    EALLOW;

    // 初始化ADC2（假设已有InitAdc2()函数）
    InitAdc2();

    // 配置ADC2
    Adc2Regs.ADCCTL2.bit.ADCNONOVERLAP = 1;     // 启用非重叠模式
    Adc2Regs.ADCCTL1.bit.INTPULSEPOS   = 1;     // 中断在结果锁存后触发
    Adc2Regs.INTSEL1N2.bit.INT1E       = 1;     // 启用ADCINT1
    Adc2Regs.INTSEL1N2.bit.INT1CONT    = 0;     // 禁用连续模式
    Adc2Regs.INTSEL1N2.bit.INT1SEL     = 0;     // EOC0触发ADCINT1

    // 配置SOC0
    Adc2Regs.ADCSOC0CTL.bit.CHSEL      = 0;     // ADC2A0通道
    Adc2Regs.ADCSOC0CTL.bit.TRIGSEL    = 0;     // 软件触发
    Adc2Regs.ADCSOC0CTL.bit.ACQPS      = 6;     // 采样窗口7个ADC时钟周期

    EDIS;
}

温度电压映射关系数组

static const LMT86_LUT_Entry lmt86_lut[] = {
    // 负温度区 (-50°C 到 -1°C)
    {-50, 2616}, {-49, 2607}, {-48, 2598}, {-47, 2589}, {-46, 2580},
    {-45, 2571}, {-44, 2562}, {-43, 2553}, {-42, 2543}, {-41, 2533},
    {-40, 2522}, {-39, 2512}, {-38, 2501}, {-37, 2491}, {-36, 2481},
    {-35, 2470}, {-34, 2460}, {-33, 2449}, {-32, 2439}, {-31, 2429},
    {-30, 2418}, {-29, 2408}, {-28, 2397}, {-27, 2387}, {-26, 2376},
    {-25, 2366}, {-24, 2355}, {-23, 2345}, {-22, 2334}, {-21, 2324},
    {-20, 2313}, {-19, 2302}, {-18, 2292}, {-17, 2281}, {-16, 2271},
    {-15, 2260}, {-14, 2250}, {-13, 2239}, {-12, 2228}, {-11, 2218},
    {-10, 2207}, {-9, 2197}, {-8, 2186}, {-7, 2175}, {-6, 2164},
    {-5, 2154}, {-4, 2143}, {-3, 2132}, {-2, 2122}, {-1, 2111},

    // 正温度区 (0°C 到 150°C)
    {0, 2100}, {1, 2089}, {2, 2079}, {3, 2068}, {4, 2057},
    {5, 2047}, {6, 2036}, {7, 2025}, {8, 2014}, {9, 2004},
    {10, 1993}, {11, 1982}, {12, 1971}, {13, 1961}, {14, 1950},
    {15, 1939}, {16, 1928}, {17, 1918}, {18, 1907}, {19, 1896},
    {20, 1885}, {21, 1874}, {22, 1864}, {23, 1853}, {24, 1842},
    {25, 1831}, {26, 1820}, {27, 1810}, {28, 1799}, {29, 1788},
    {30, 1777}, {31, 1766}, {32, 1756}, {33, 1745}, {34, 1734},
    {35, 1723}, {36, 1712}, {37, 1701}, {38, 1690}, {39, 1679},
    {40, 1668}, {41, 1657}, {42, 1646}, {43, 1635}, {44, 1624},
    {45, 1613}, {46, 1602}, {47, 1591}, {48, 1580}, {49, 1569},
    {50, 1558}, {51, 1547}, {52, 1536}, {53, 1525}, {54, 1514},
    {55, 1503}, {56, 1492}, {57, 1481}, {58, 1470}, {59, 1459},
    {60, 1448}, {61, 1436}, {62, 1425}, {63, 1414}, {64, 1403},
    {65, 1391}, {66, 1380}, {67, 1369}, {68, 1358}, {69, 1346},
    {70, 1335}, {71, 1324}, {72, 1313}, {73, 1301}, {74, 1290},
    {75, 1279}, {76, 1268}, {77, 1257}, {78, 1245}, {79, 1234},
    {80, 1223}, {81, 1212}, {82, 1201}, {83, 1189}, {84, 1178},
    {85, 1167}, {86, 1155}, {87, 1144}, {88, 1133}, {89, 1122},
    {90, 1110}, {91, 1099}, {92, 1088}, {93, 1076}, {94, 1065},
    {95, 1054}, {96, 1042}, {97, 1031}, {98, 1020}, {99, 1008},
    {100, 997}, {101, 986}, {102, 974}, {103, 963}, {104, 951},
    {105, 940}, {106, 929}, {107, 917}, {108, 906}, {109, 895},
    {110, 883}, {111, 872}, {112, 860}, {113, 849}, {114, 837},
    {115, 826}, {116, 814}, {117, 803}, {118, 791}, {119, 780},
    {120, 769}, {121, 757}, {122, 745}, {123, 734}, {124, 722},
    {125, 711}, {126, 699}, {127, 688}, {128, 676}, {129, 665},
    {130, 653}, {131, 642}, {132, 630}, {133, 618}, {134, 607},
    {135, 595}, {136, 584}, {137, 572}, {138, 560}, {139, 549},
    {140, 537}, {141, 525}, {142, 514}, {143, 502}, {144, 490},
    {145, 479}, {146, 467}, {147, 455}, {148, 443}, {149, 432},
    {150, 420}
};

使用线性插值计算温度

// 使用线性插值计算温度
static float VoltageToTemperature(float voltage_mV)
{
    Uint16 i;
    float slope;
    // 边界检查
    if (voltage_mV >= lmt86_lut[0].voltage) return lmt86_lut[0].temp;
    if (voltage_mV <= lmt86_lut[LMT86_LUT_SIZE-1].voltage) return lmt86_lut[LMT86_LUT_SIZE-1].temp;

    // 线性搜索(实际使用时建议改为二分查找)
    for (i=0; i<LMT86_LUT_SIZE-1; i++) {
        if (voltage_mV <= lmt86_lut[i].voltage && voltage_mV >= lmt86_lut[i+1].voltage) {
            // 线性插值
            slope = (lmt86_lut[i+1].temp - lmt86_lut[i].temp) / (float)(lmt86_lut[i+1].voltage - lmt86_lut[i].voltage);
            return lmt86_lut[i].temp + slope * (voltage_mV - lmt86_lut[i].voltage);
        }
    }
        return 0.0f; // 不应执行到此处
}

读取当前温度(°C)

// 读取当前温度(°C)
float TempSensor_ReadTemperature(Uint16 adcValue)
{
    float voltage_mV = ADC_ToVoltage(adcValue);
    return VoltageToTemperature(voltage_mV);
}

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