MAX1233/MAX1234触摸屏控制器入门

时间：03-17 来源：互联网点击：

T W AC 2b01	Trigger ADC scan of TEMP1; ADC control word 0x2b01 means: ADC_control_wr_demand_scan ADC_control_ AD1010 /* measure TEMP1 / ADC_control_RES11 / 12-bit resolution / ADC_control_AVG00 / no averaging / ADC_control_CNR00 / conversion rate 3.5μs / ADC_control_RFV / RFV=1: VREF=2.5V */	0x0040 0x2b01
T R T1	Read TEMP1 result TEMP1 _code	0x8009 0x0000
T MC	Measure TEMP1, TEMP2 with 12-bit resolution and 3.5μs conversion rate	0x0040 0x3301 0x8009 0x0000 0x800a 0x0000
T W AC 3301	Trigger ADC scan of TEMP1 and TEMP2; ADC control word 0x3301 means: ADC_control_wr_demand_scan ADC_control_ AD 1100 /* measure TEMP1,TEMP2 / ADC_control_RES11 / 12-bit resolution / ADC_control_AVG00 / no averaging / ADC_control_CNR00 / conversion rate 3.5μs / ADC_control_RFV / RFV=1: VREF=2.5V */	0x0040 0x3301
T R T1	Read TEMP1 result TEMP1 _code	0x8009 0x0000
T R T2	Read TEMP2 result TEMP2 _code	0x800a 0x0000

2.8) 将TEMP1转换结果译为物理值

下面的C/C++伪代码片断总结了DEMO1234程序是怎样解释TEMP1转换结果的。

    /* ADC control resolution value selects num_codes 4096 (12-bit), 1024 (10-bit), or 256 (8-bit) */int num_codes = 4096; /* ADC_control_RES11: 12-bit resolution *//* Voltage that corresponds to the full-scale ADC code; may be internal 1V or 2.5V ref, or ext ref. */double ADC_fullscale_voltage = 2.5; /* ADC_control_RFV=1: VREF=2.5V.  RFV=0: VREF=1.0V. *//* TEMP1_code is the 16-bit result read by SPI command 0x8009 */double TEMP1_Voltage = (TEMP1_code * ADC_fullscale_voltage) / num_codes;/* Calibration values */const double Temp1V_Room = 0.590; // temp1 voltage at room temperature 25Cconst double Temp1K_Room = 298.15;  // Room temperature Kelvins (298.15K=25C)const double Temp1V_Per_K = -0.002; // TempCo -2mV per degree C/* Convert to absolute temperature */double Kelvin = (TEMP1_Voltage - Temp1V_Room) / Temp1V_Per_K + Temp1K_Room;/* Optional conversion to commonly used temperature units */double Centigrade = Kelvin - 273.15;double Fahrenheit = (Centigrade * 9.0 / 5.0) + 32;

2.9) 将TEMP1和TEMP2转换结果译为物理值

下面的C/C++伪代码片断总结了DEMO1234程序是怎样解释TEMP1和TEMP2转换结果的。TEMP2只在和TEMP1对比时才有意义。

    /* ADC control resolution value selects num_codes 4096 (12-bit), 1024 (10-bit), or 256 (8-bit) */int num_codes = 4096; /* ADC_control_RES11: 12-bit resolution *//* Voltage that corresponds to the full-scale ADC code; may be internal 1V or 2.5V ref, or ext ref. */double ADC_fullscale_voltage = 2.5; /* ADC_control_RFV=1: VREF=2.5V.  RFV=0: VREF=1.0V. *//* TEMP1_code is the 16-bit result read by SPI command 0x8009 */double TEMP1_Voltage = (TEMP1_code * ADC_fullscale_voltage) / num_codes;/* TEMP2_code is the 16-bit result read by SPI command 0x800a */double TEMP2_Voltage = (TEMP2_code * ADC_fullscale_voltage) / num_codes;/* Calibration values */const double K_Per_Temp21_Delta_V = 2680.0; // nominal 2680 5/27/2002/* Convert to absolute temperature */double Kelvin = (TEMP2_Voltage - TEMP1_Voltage) * K_Per_Temp21_Delta_V;/* Optional conversion to commonly used temperature units */double Centigrade = Kelvin - 273.15;double Fahrenheit = (Centigrade * 9.0 / 5.0) + 32;

2.10) 测量外部电压输入AUX1、AUX2、BAT1、BAT2和温度

表9. ADC测量命令序列

DEMO1234 Command

Action (Triggered by A/D3210 Bits)

SPI data in

T MB

Measure BAT1/4, BAT2/4, AUX1, AUX2, TEMP1, TEMP2 with 12-bit resolution and 3.5μs conversion rate

0x0040 0x2f01

0x8005 0x0000

0x8006 0x0000

0x8007 0x0000

0x8008 0x0000

0x8009 0x0000

0x800a 0x0000

T W AC 2f01

Trigger ADC scan of BAT1-2, AUX1-2, TEMP1-2;
ADC control word 0x2f01 means:
ADC_control_wr_demand_scan
ADC_control_ AD1011 /* measure AUX1 etc. */
ADC_control_RES11 /* 12-bit resolution */
ADC_control_AVG00 /* no averaging */
ADC_control_CNR00 /* conversion rate 3.5μs */
ADC_control_RFV /* RFV=1: VREF=2.5V */

0x0040 0x2f01

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