MAX1233/MAX1234触摸屏控制器入门

• Maxim MAX1234评估板 (MAX1234EVKIT)
• Maxim MINIQUSB+ (包括USB A-B电缆和MINIQUSB-X+扩展板)
• Windows® 2000/XP PC，支持USB。
• 四线阻性触摸屏(例如，PDA数字转换器/玻璃屏等)
• 可选：测量DAC输出电压的DMM
• 可选：驱动AUX和BAT输入的电压源
• 可选：示波器，用于观察/PENIRQ和/KEYIRQ引脚上的自动扫描中断脉冲。

1. 按照表1连接MAX1234评估板连接器J1和MINIQUSB-X+扩展电路板(包含在MINIQUSB+中)。可以采用3M®内部连接器922576-40来替代连接MAX1234评估板的焊线，将其插入到J1中，以提供方便的连接点。不要连接终端模块TB1。
   
   表1. MAX1234评估板和MINIQUSB+电路板之间的连接设置 MAX1234 SignalMAX1234 EV KitMINIQUSB-X+MINIQUSB SignalGNDJ1-1H2-8GNDV_CCJ1-7H2-13.3V supply from MINIQUSB+BUSY-BarJ1-27H2-7GPIO-K7 (MAXQ2000-INT2)PENIRQ-BarJ1-29H1-3GPIO-K6 (MAXQ2000-INT1)KEYIRQ-BarJ1-31H1-8GPIO-K5 (MAXQ2000-INT0)DOUTJ1-35*H2-2MISO (SPI master in, slave out)DINJ1-36*H2-5MOSI (SPI master out, slave in)SCLKJ1-37*H2-3SCLK (SPI clock)CS-BarJ1-38H2-4CS-bar (SPI chip select)USB+5VJ1-5J4-7USB+5V supply from PC* 注释：必须通过连接器J1来驱动MAX1234评估板数字输入，不能直接将其驱动至U1周围的测试点。必须采用板上MAX1841电平转换器来驱动MAX1234评估板数字信号。
   
   
2. 将MINIQUSB+插入到扩展板的顶部。
3. 连接MINIQUSB+和PC的USB端口。如果这是MINIQUSB+第一次和PC连接，将出现即插即用向导。指南窗口将提示器件驱动器(它包含在随附zip文件中)的安装位置。
4. 启动固件更新批处理文件FWUPDATE.BAT来更新MINIQUSB+固件。
5. 固件更新完成后，从PC的USB端口断开MINIQUSB+。

1. 将MAX1234评估板跳接器JU1设置到“MAX1234”位置。
2. 将MINIQUSB+连接至PC的USB端口。确定DACOUT电压 = mid-scale (2.2V)。
3. 启动DEMO1234.EXE程序。屏幕上将出现控制台。
4. 在控制台中输入下面的命令序列。

DEMO1234 Command*Expected Program Output

SPI data inVerification**

C

Board connected.Got board banner: Maxim MINIQUSB V01.05.41 Firmware version is OK. (configured for SPI auto-CS 4-byte mode) (SCLK=2MHz) ...

T W DD FF

Write_Register(regAddr=0x000b wr_DAC_data , data=http:///article/88/131/app/2008/0x00ff (no bits defined for this register)) result = 10x000b 0x00ffDACOUT = full-scale (4.5V)

T R DD

Read_Register(regAddr=0x800b wr_DAC_data ) result = 1, buffer = 0x00ff = 255 (no bits defined for this register)0x800b 0x0000Data buffer = 0x00ff

T W DD 80

Write_Register(regAddr=0x000b wr_DAC_data , data=http:///article/88/131/app/2008/0x0080 (no bits defined for this register)) result = 10x000b 0x0080DACOUT = mid-scale (2.2V)

T R DD

Read_Register(regAddr=0x800b wr_DAC_data ) result = 1, buffer = 0x0080 = 128 (no bits defined for this register)0x800b 0x0000data buffer = 0x0080* DEMO1234 Command命令列出了输入到DEMO1234.exe程序中的命令。
** Verification列出了可以进行的物理测试，验证所执行的命令。

1.5) SPI data in实例格式SPI data in一列列出了驱动至MAX1233/MAX1234 DIN引脚的SPI数据，采用了十六进制格式，最高有效字节在前。例如，序列0x000b 0x00ff中的SPI数据表示同步输入到DIN的32位序列是0000 0000 0000 1011 0000 0000 1111 1111。第一位0用于寄存器写操作，1用于寄存器读操作。

寄存器写操作是0000 0000 a7-a0 d15-d0格式的32位SPI传送过程。
寄存器读操作是1000 0000 a7-a0 0000 0000格式的32位SPI传送过程，在最后16位，接收到的数据从DOUT同步输入。

2) 模拟I/O实例下面的例子介绍了怎样使用DEMO1234.EXE程序来控制DAC输出，配置基准电压，测量AUX1/AUX2/BAT1/BAT2电压输入，以及测量内部MAX1234温度。

2.1) 控制DAC输出电压由两个寄存器来控制DAC。写入DAC数据寄存器来设置输出电压。写入DAC控制寄存器来关断或者对DAC上电。默认上电状态是DAC加电，DAC输出位于量程中部。DAC满量程电压通常为AV_DD的90% (最小85%，最大95%)。

对于AV_DD = 3.3V ±5%，DACOUT满量程范围在2.65V和3.27V之间，通常为2.96V。
对于AV_DD = 5.0V ±5%，DACOUT满量程范围在4.02V和4.97V之间，通常为4.48V。

表3. DAC输出命令

DEMO1234 CommandAction

SPI data inMAX1233 (3.3V)MAX1234 (5.0V)

T W DD FFDACOUT = full-scale

0x000b 0x00ffDACOUT = 2.96VDACOUT = 4.48V

T W DD 00DACOUT = 0V

0x000b 0x0000DACOUT = 0.0VDACOUT = 0.0V

T W DD 80DACOUT = mid-scale

0x000b 0x0080DACOUT = 1.485VDACOUT = 2.25V

T W DC 8000Disable DAC

0x0042 0x8000DACOUT = 0.0VDACOUT = 0.0V

T W DC 0Enable DAC

0x0042 0x0000DACOUT = 1.485VDACOUT = 2.25V
2.2) 选择ADC基准电源模式ADC需要一个基准电压。对于典型的嵌入式系统工作，默认设置是fine。在自动上电模式(ADC3210 = 0000，RES10 = 00)下，MAX1233/MAX1234提供自己的内部基准电压。在每次测量之前，内部基准自动上电，测量完成后关断。

对于第一次诊断，保持上电模式(ADC3210 = 0000，RES10 = 01)支持使用手持式DVM对基准电压进行外部验证。

ADC扫描选择位设置为0000，写入ADC控制寄存器(0x40)，来设置ADC基准电源模式。RES1/RES0位选择基准电源模式，基准控制位RFV选择内部1.0V或者2.5V基准(请参考MAX1233/MAX1234数据资料的表13)。

ADC控制字：x x 0 0 0 0 RES1 RES0 x x x x x x x RFV

表4. 内部基准命令

DEMO1234 CommandAction

SPI data inVerification

T W AC 0100Internal 1V reference always powered; write ADC control word with
ADC3210 = 0000,
RES10 = 01,
RFV = 0

0x0040 0x0100Voltage at pin 12 REF is between 0.98V and 1.02V

T W AC 0101Internal 2.5V reference always powered; write ADC control word with
ADC3210 = 0000,
RES10 = 01,
RFV = 1

0x0040 0x0101Voltage at pin 12 REF is between 2.47V and 2.53V

T W AC 0001Internal 2.5V reference powered when needed; write ADC control word with
ADC3210 = 0000,
RES10 = 00,
RFV = 1

0x0040 0x0001Voltage at pin 12 REF will be powered only briefly as necessary
表5. 外部基准命令

DEMO1234 CommandAction

SPI data in

T W AC 0300External reference must be provided;
ADC_control_wr_demand_scan:(write)demand scan
ADC_control_AD0000:configure reference
ADC_control_RES11:external reference

0x0040 0x0300
2.3) 测量外部电压输入AUX1和AUX2表6. ADC测量命令序列

DEMO1234 CommandAction (Triggered by A/D3210 Bits)

SPI data in

T M8Measure AUX1 with 12-bit resolution and 3.5µs conversion rate

0x0040 0x2301

0x8007 0x0000

T W AC 2301Trigger ADC scan of AUX1;
ADC control word 0x2301 means:
ADC_control_wr_demand_scan
ADC_control_AD1000 /* measure AUX1 */
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 0x2301

T R A1Read AUX1 result AUX1_code

0x8007 0x0000

T M9Measure AUX2 with 12-bit resolution and 3.5µs conversion rate

0x0040 0x2701

0x8008 0x0000
2.4) 将AUX1和AUX2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AUX1和AUX2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. */ /* AUX1_code is the 16-bit result read by SPI command 0x8007 */ double AUX1_Voltage = (AUX1_code * ADC_fullscale_voltage) / num_codes; /* AUX2_code is the 16-bit result read by SPI command 0x8008 */ double AUX2_Voltage = (AUX2_code * ADC_fullscale_voltage) / num_codes;2.5) 测量外部电压输入BAT1和BAT2表7. ADC测量命令序列

DEMO1234 CommandAction (Triggered by A/D3210 Bits)

SPI data in

T M6Measure BAT1 with 12-bit resolution and 3.5µs conversion rate

0x0040 0x1b01

0x8005 0x0000

T W AC 1b01Trigger ADC scan of BAT1;
ADC control word 0x1b01 means:
ADC_control_wr_demand_scan
ADC_control_AD0110 /* measure BAT1 */
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 0x1b01

T R B1Read BAT1 result BAT1_code

0x8005 0x0000

T W AC 1b21Trigger ADC scan of BAT1;
ADC control word 0x1b21 means:
ADC_control_wr_demand_scan
ADC_control_AD0110 /* measure BAT1 */
ADC_control_RES11 /* 12-bit resolution */
ADC_control_AVG00 /* no averaging */
ADC_control_CNR10 /* conversion rate 10µs */
ADC_control_RFV /* RFV=1: VREF=2.5V */

0x0040 0x1b21

T R B1Read BAT1 result BAT1_code

0x8005 0x0000

T M7Measure BAT2 with 12-bit resolution and 3.5µs conversion rate

0x0040 0x1f01

0x8006 0x0000
2.6) 将BAT1和BAT2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BAT1和BAT2转换结果的。注意：通过一个4:1输入分配器来测量BAT1和BAT2。

/* 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. */ /* Note: BAT1 and BAT2 measure through a 4:1 input divider. */ /* BAT1_code is the 16-bit result read by SPI command 0x8005 */ double BAT1_Voltage = 4 * (BAT1_code * ADC_fullscale_voltage) / num_codes; /* BAT2_code is the 16-bit result read by SPI command 0x8006 */ double BAT2_Voltage = 4 * (BAT2_code * ADC_fullscale_voltage) / num_codes;2.7) 测量内部温度TEMP1和TEMP2表8. ADC测量命令序列

DEMO1234 CommandAction (Triggered by A/D3210 Bits)

SPI data in

T MAMeasure TEMP1 with 12-bit resolution and 3.5µs conversion rate

0x0040 0x2b01

0x8009 0x0000

T W AC 2b01Trigger 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 T1Read TEMP1 result TEMP1 _code

0x8009 0x0000

T MCMeasure TEMP1, TEMP2 with 12-bit resolution and 3.5µs conversion rate

0x0040 0x3301

0x8009 0x0000

0x800a 0x0000

T W AC 3301Trigger ADC scan of TEMP1 and TEMP2;
ADC control word 0x3301 means:
ADC_control_wr_demand_scan
ADC_control_ AD1100 /* 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 T1Read TEMP1 result TEMP1 _code

0x8009 0x0000

T R T2Read 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 25C const 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 CommandAction (Triggered by A/D3210 Bits)

SPI data in

T MBMeasure 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 2f01Trigger 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

T R B1Read BAT1 result BAT1 _code

0x8005 0x0000

T R B2Read BAT2 result BAT2_code

0x8006 0x0000

T R A1Read AUX1 result AUX1 _code

0x8007 0x0000

T R A2Read AUX2 result AUX2 _code

0x8008 0x0000

T R T1Read TEMP1 result TEMP1 _code

0x8009 0x0000

T R T2Read TEMP2 result TEMP2 _code

0x800a 0x0000
3) 触摸屏实例下面的例子解释了怎样使用DEMO1234.EXE程序来获得触摸屏数据。

3.1) 低成本商用触摸屏在互联网上搜索"PDA Digitizer/Glasstop"，寻找合适的替代触摸屏。高清触摸屏玻璃的价格范围在50美元至10美元之间，价格取决于型号以及玻璃是否全部贴在显示屏上。

3.2) 连接触摸屏和评估板MAX1234评估板提供突出插头H5/H6来连接10mm柔性电缆或者长度更短的电缆。H6连接器的间距是0.5mm，比实际触摸屏柔性电缆间距更精细。把柔性电缆插入H6，上锁，选择位于四条柔性电缆中每一电缆中心位置的H5引脚。跳接器连接H5和标有U1的X+、Y+、X-以及Y-测试点。

3.3) 检验触摸屏的连接第一次连接触摸屏时，通过下面的步骤来验证X和Y连接是否正确。可以有几个触摸屏交叉连接，但大部分不会正常工作。在这些例子中，我们假设X- = left，X+ = right，Y- = top，Y+ = bottom。

表10. 触摸屏物理连接验证命令序列

DEMO1234 CommandAction

SPI data inVerificationConnect DVM to X+/GND

T MDNo measurement; drive Y+,Y-

0x0040 0x3701Touch top leftX+ = approx. Y-Touch top rightX+ = approx. Y-Touch bottom leftX+ = approx. Y+Touch bottom rightX+ = approx. Y+Connect DVM to Y+/GND

T MENo measurement; drive X+,X-

0x0040 0x3b01Touch top leftY+ = approx. X-Touch top rightY+ = approx. X+Touch bottom leftY+ = approx. X-Touch bottom rightY+ = approx. X+
表11. 纠正触摸屏连接问题 SymptomCorrectionTouch coordinates are mirrored top-to-bottomSwap the Y+ and Y- connectionsTouch coordinates are mirrored left-to-rightSwap the X+ and X- connectionsTouch coordinates are rotated 180 degreesSwap the X+ and X- connections, and swap the Y+ and Y- connectionsTouch coordinates are mirrored diagonallySwap the X+ and Y+ connections, and swap the X- and Y- connectionsTouch coordinates do not seem to track, and the distortion is not a simple flip/rotate/mirror transformationSwap the X+ and Y+ connections;
if distortion persists, swap the X+ and Y- connections;
if distortion still persists, disconnect touch screen and use DVM to verify X+ to X- resistance and Y+ to Y- resistance;
verify with no touch X+ and X- are isolated from Y+ and Y-
3.4) 检测触摸屏的操作：根据需要扫描在配置MAX1234检测触摸屏操作，根据需要数字化接触屏的位置时，写入寄存器0x40 (ADC控制)，其PENSTS=0，ADSTS=0 (请参考MAX1233/MAX1234数据资料的表6)。读取寄存器0x00 (X轴)后，检测到后续的触摸屏操作时，/PENIRQ信号锁存至低电平，在写入ADC控制寄存器测量X、Y轴之前，保持低电平。

表12. 触摸屏检测命令序列：根据需要扫描

DEMO1234 CommandAction

SPI data inVerification

T W AC 0b01Demand scan

0x0040 0x0b01

T R AXRead conversion result register X

0x8000 0x0000

P R 6Read PENIRQ-bar pin statusPENIRQ = 1Touch the touch screen

P R 6Read PENIRQ-bar pin statusPENIRQ = 0

T M2Measure X,Y,Z1,Z2

0x0040 0x0b01

0x8000 0x0000

0x8001 0x0000

0x8002 0x0000

0x8003 0x0000

P R 6Read PENIRQ-bar pin statusPENIRQ = 1Touch and hold the touch screen

P R 6Read PENIRQ-bar pin statusPENIRQ = 0

T M2Measure X,Y,Z1,Z2

0x0040 0x0b01

0x8000 0x0000

0x8001 0x0000

0x8002 0x0000

0x8003 0x0000

P R 6Read PENIRQ-bar pin statusPENIRQ = 0

T M2Measure X,Y,Z1,Z2

0x0040 0x0b01

0x8000 0x0000

0x8001 0x0000

0x8002 0x0000

0x8003 0x0000

P R 6Read PENIRQ-bar pin statusPENIRQ = 0Release the touch screen

P R 6Read PENIRQ-bar pin statusPENIRQ = 0

T M2Measure X,Y,Z1,Z2

0x0040 0x0b01

0x8000 0x0000

0x8001 0x0000

0x8002 0x0000

0x8003 0x0000

P R 6Read PENIRQ-bar pin statusPENIRQ = 1
3.5) 检测触摸屏操作：自动扫描在检测触摸屏操作，配置MAX1234，自动数字化触摸屏的接触位置时，写入寄存器0x40 (ADC控制)，其PENSTS=1，ADSTS=0 (请参考MAX1233/MAX1234数据资料的表6)。第一次接触屏幕时，/PENIRQ信号暂时变为低电平，并在读取X寄存器之前不会变化。

表13. 触摸屏检测命令序列：自动扫描

DEMO1234 CommandAction

SPI data inVerificationOptional: connect oscilloscope to PENIRQ-bar

I C 1 3Configure PENIRQ-bar pulse accumulator: falling-edge trigger

I 0 1Reset the pulse accumulator

I R 1Read the number of times PENIRQ-bar has pulsed lowcount = 0

T W AC 8bffWait for touch, then scan X,Y,Z1,Z2

0x0040 0x8bffTouch the touch screenPENIRQ pulse

I R 1Read the number of times PENIRQ-bar has pulsed lowcount has increased

T R PRead X,Y,Z1,Z2 conversion results

0x8000 0x0000

0x8001 0x0000

0x8002 0x0000

0x8003 0x0000Touch the touch screenPENIRQ pulse

I R 1Read the number of times PENIRQ-bar has pulsed lowcount has increased

T R PRead X,Y,Z1,Z2 conversion results

0x8000 0x0000

0x8001 0x0000

0x8002 0x0000

0x8003 0x0000Touch the touch screenPENIRQ pulse

I R 1Read the number of times PENIRQ-bar has pulsed lowcount has increased

T R PRead X,Y,Z1,Z2 conversion results

0x8000 0x0000

0x8001 0x0000

0x8002 0x0000

0x8003 0x0000
4) 键盘和通用输入/输出引脚下面的例子介绍了怎样使用DEMO1234.EXE程序来扫描键盘，怎样使用GPIO键盘扫描引脚。

4.1) 配置键盘和GPIO引脚GPIO控制寄存器将每个C1–C4和R1–R4引脚分别配置为输入、输出或者是键盘的一部分(请参考MAX1233/MAX1234数据资料的表2**表27)。此外，写入GPIO上拉禁止寄存器，将输出引脚配置为开漏输出。

表14. 键盘和GPIO配置实例

DEMO1234 CommandAction

SPI data in

T W GC FFFFKeypad: none;
GPIO outputs: C4,C3,C2,C1,R4,R3,R2,R1;
GPIO inputs: none

0x004f 0xffff

T W GC FF00Keypad: none;
GPIO outputs: none;
GPIO inputs: C4,C3,C2,C1,R4,R3,R2,R1

0x004f 0xff00

T W GC 0000Keypad: (C4,C3,C2,C1) x (R4,R3,R2,R1);
GPIO outputs: none;
GPIO inputs: none

0x004f 0x0000

T W GC C8C0Keypad: (C2,C1) x (R3,R2,R1);
GPIO outputs: C4,C3;
GPIO input: R4

0x004f 0xc8c0

T W GP 4000GPIO pullup disable: C3

0x004e 0x4000
4.2) 读写GPIO引脚GPIO数据寄存器读取GPIO输入引脚，写入GPIO输出引脚。注意：在这些例子中，C3、C4和R4是引脚名称，而不是元件名称。

表15. GPIO实例

DEMO1234 CommandAction

SPI data inVerification

T W GC C8C0Keypad:
(C2,C1) x (R3,R2,R1);
GPIO outputs: C4,C3;
GPIO input: R4

0x004f 0xc8c0

T W GP 4000GPIO pullup disable: C3

0x004e 0x4000Connect external resistor between C3 pin and DVDDConnect DVM to C4 pin

T W GD 8000GPIO write C4 = 1

0x000f 0x8000C4 pin = high

T W GD 0000GPIO write C4 = 0

0x000f 0x0000C4 pin = low

T W GD 8000GPIO write C4 = 1

0x000f 0x8000C4 pin = high

T W GD 0000GPIO write C4 = 0

0x000f 0x0000C4 pin = lowConnect DVM to C3 pin

T W GD 4000GPIO write C3 = 1

0x000f 0x4000C3 pin = high

T W GD 0000GPIO write C3 = 0

0x000f 0x0000C3 pin = low

T W GD 4000GPIO write C3 = 1

0x000f 0x4000C3 pin = high

T W GD 0000GPIO write C3 = 0

0x000f 0x0000C3 pin = lowConnect R4 pin to DVDD

T R GDGPIO read

0x800f 0x0000Buffer = 0x0800Connect R4 pin to GND

T R GDGPIO read

0x800f 0x0000Buffer = 0x0000
4.3) 检测按键：自动扫描可以配置键盘控制寄存器在探测到有按键按下时，自动扫描键盘。

表16. 按键命令序列：自动扫描

DEMO1234 CommandAction

SPI data inVerificationOptional: connect oscilloscope to KEYIRQ-bar

I C 0 3Configure KEYIRQ-bar pulse accumulator: falling-edge trigger

I 0 0Reset the pulse accumulator

I R 0Read the number of times KEYIRQ-bar has pulsed lowcount = 0

T W GC 0000Keypad:
(C4,C3,C2,C1) x (R4,R3,R2,R1);
GPIO outputs: none;
GPIO inputs: none

0x004f 0x0000

T W KC bf00Wait for keypress;
maximum debounce and hold times

0x0041 0xbf00Press and release R1C1 (key "1")KEYIRQ pulse

I R 0Read the number of times KEYIRQ-bar has pulsed lowcount has increased

T R KBRead raw keypad result

0x8004 0x00000x0001 = R1C1 keyPress and release R2C2 (key "5")KEYIRQ pulse

I R 0Read the number of times KEYIRQ-bar has pulsed lowcount has increased

T R KBRead raw keypad result

0x8004 0x00000x0020 = R2C2 keyPress and release R3C2 (key "8")KEYIRQ pulse

I R 0Read the number of times KEYIRQ-bar has pulsed lowcount has increased

T R KBRead raw keypad result

0x8004 0x00000x0040 = R3C2 key
4.4) 从键盘中屏蔽单个按键使用键盘屏蔽寄存器和键盘2结果寄存器来屏蔽每个按键。屏蔽掉的按键被扫描至KPD寄存器，但是不在键盘2结果寄存器中报告。

表17. 按键命令序列：屏蔽单个按键

DEMO1234 CommandAction

SPI data inVerification

T W GC 0000Keypad:
(C4,C3,C2,C1) x (R4,R3,R2,R1);
GPIO outputs: none;
GPIO inputs: none

0x004f 0x0000

T W KC bf00Wait for keypress;
maximum debounce and hold times

0x0041 0xbf00

T W KM 0020Mask only R2C2 key

0x0050 0x0020Press and release R1C1 (key "1")

T R KBRead raw keypad result

0x8004 0x00000x0001 = R1C1 key

T R K2Read masked keypad result

0x8011 0x00000x0001 = R1C1 keyPress and release R2C2 (key "5")

T R KBRead raw keypad result

0x8004 0x00000x0020 = R2C2 key

T R K2Read masked keypad result

0x8011 0x00000x0000 = no keyPress and release R3C2 (key "8")

T R KBRead raw keypad result

0x8004 0x00000x0040 = R3C2 key

T R K2Read masked keypad result

0x8011 0x00000x0040 = R3C2 key
4.5) 从键盘中屏蔽一列使用键盘列寄存器来屏蔽所有列。不扫描屏蔽列，因此，KPD寄存器不会探测这些列中的按键。

表18. 按键命令序列：屏蔽键盘的一列

DEMO1234 CommandAction

SPI data inVerification

T W GC 0000Keypad:
(C4,C3,C2,C1) x (R4,R3,R2,R1);
GPIO outputs: none;
GPIO inputs: none

0x004f 0x0000

T W KC bf00Wait for keypress;
maximum debounce and hold times

0x0041 0xbf00

T W KK 2000Mask entire C2 column

0x0051 0x2000Press and release R1C1 (key "1")

T R KBRead raw keypad result

0x8004 0x00000x0001 = R1C1 keyPress and release R2C2 (key "5")

T R KBRead raw keypad result

0x8004 0x0000(previous value)Press and release R3C2 (key "8")

T R KBRead raw keypad result

0x8004 0x0000(previous value)Press and release R2C3 (key "6")

T R KBRead raw keypad result

0x8004 0x00000x0200 = R2C3 key
5) 电源管理表19. 关断命令

DEMO1234 CommandAction

SPI data inVerification

T W AC C000Power off ADC

0x0040 0xc000—

T W AC 0300Power off internal reference

0x0040 0x0300REF = not driven

T W DC 8000Disable DAC

0x0042 0x8000DACOUT = 0.0V

T W KC C000Power off keypad

0x0041 0xc000—
6) 菜单系统全部源代码实现下面的控制台菜单系统，它连接至MINIQUSB+模块。

CmodComm测试程序主菜单—在连接前
A) adjust timing parameters
L) CmodLog... functions
C) connect
D) Debug Messages
X) exit

对C (连接)命令的响应
C
Hardware supports optimized native SMBus commands.

Board connected.

Got board banner: Maxim MINIQUSB V01.05.41
Firmware version is OK.
(configured for SPI auto-CS 4-byte mode) (SCLK=2MHz) ...

主菜单—连接后有效
T) Test the device
8) CmodP8Bus... functions
A) adjust timing parameters
L) CmodLog... functions
P) CmodPin... functions
S) CmodSpi... functions
M) CmodSMBus... functions
) CmodCommStringWrite list of hex codes

R) CmodBoardReset
D) Disconnect

测试菜单命令—连接后有效
R) Read register
W) Write register
M0) measure no measurement; configure reference
M1) measure X,Y
M2) measure X,Y,Z1,Z2
M3) measure X
M4) measure Y
M5) measure Z1,Z2
M6) measure BAT1/4
M7) measure BAT2/4
M8) measure AUX1
M9) measure AUX2
MA) measure TEMP1
MB) measure BAT1/4,BAT2/4,AUX1,AUX2,TEMP1,TEMP2
MC) measure TEMP1,TEMP2
MD) no measurement; drive Y+,Y-
ME) no measurement; drive X+,X-
MF) no measurement; drive Y+,X-
.) Exit this menu

6.1) 寄存器读/写命令表20. 读取寄存器助记符

DEMO1234 CommandMnemonic

SPI data in

T R A1Test Read AUX1 register

0x8007 0x0000

T R A2Test Read AUX2 register

0x8008 0x0000

T R ACTest Read ADC_control register

0x8040 0x0000

T R AXTest Read X register

0x8000 0x0000

T R AYTest Read Y register

0x8001 0x0000

T R AZ1Test Read Z1 register

0x8002 0x0000

T R AZ2Test Read Z2 register

0x8003 0x0000

T R B1Test Read BAT1 register

0x8005 0x0000

T R B2Test Read BAT2 register

0x8006 0x0000

T R DCTest Read DAC_control register

0x8042 0x0000

T R DDTest Read DAC_data register

0x800b 0x0000

T R GCTest Read GPIO_control register

0x804f 0x0000

T R GDTest Read GPIO_data register

0x800f 0x0000

T R GPTest Read GPIO_pullup register

0x804e 0x0000

T R K1Test Read KPDATA1 register

0x8010 0x0000

T R K2Test Read KPDATA2 register

0x8011 0x0000

T R KBTest Read KPD register

0x8004 0x0000

T R KCTest Read KEY_control register

0x8041 0x0000

T R KKTest Read KPCOLMASK register

0x8051 0x0000

T R KMTest Read KPKEYMASK register

0x8050 0x0000

T R T1Test Read TEMP1 register

0x8009 0x0000

T R T2Test Read TEMP2 register

0x800a 0x0000
表21. 写入寄存器助记符

DEMO1234 CommandMnemonic

SPI data in

T W AC hexValueTest Write ADC_control register

0x0040 hexValue

T W DC hexValueTest Write DAC_control register

0x0042 hexValue

T W DD hexValueTest Write DAC_data register

0x000b hexValue

T W GC hexValueTest Write GPIO_control register

0x004f hexValue

T W GD hexValueTest Write GPIO_data register

0x000f hexValue

T W GP hexValueTest Write GPIO_pullup register

0x004e hexValue

T W KC hexValueTest Write KEY_control register

0x0041 hexValue

T W KK hexValueTest Write KPCOLMASK register

0x0051 hexValue

T W KM hexValueTest Write KPKEYMASK register

0x0050 hexValue
表22. 触摸屏测量命令序列

DEMO1234 CommandAction (Triggered by A/D3210 Bits)

SPI data in Sequence

T M1Measure X,Y

0x0040 0x0701

0x8000 0x0000

0x8001 0x0000

T M2Measure X,Y,Z1,Z2

0x0040 0x0b01

0x8000 0x0000

0x8001 0x0000

0x8002 0x0000

0x8003 0x0000

T M3Measure X

0x0040 0x0f01

0x8000 0x0000

T M4Measure Y

0x0040 0x1301

0x8001 0x0000

T M5Measure Z1,Z2

0x0040 0x1701

0x8002 0x0000

0x8003 0x0000

T MDNo measurement; drive Y+,Y-

0x0040 0x3701

T MENo measurement; drive X+,X-

0x0040 0x3b01

T MFNo measurement; drive Y+,X-

0x0040 0x3f01
6.2) 中断和状态引脚命令表23. 引脚状态读取命令

DEMO1234 CommandAction

SPI data in

P R 5Read KEYIRQ-bar pin statusN/A

I C 0 3Enable KEYIRQ-bar falling-edge trigger pulse accumulatorN/A

I C 0 1Enable KEYIRQ-bar rising-edge trigger pulse accumulatorN/A

I C 0 0Disable KEYIRQ-bar pulse accumulatorN/A

I R 0Read the number of times KEYIRQ-bar has pulsed lowN/A

I 0 0Clear the KEYIRQ-bar pulse accumulatorN/A

P R 6Read PENIRQ-bar pin statusN/A

I C 1 3Enable PENIRQ-bar falling-edge trigger pulse accumulatorN/A

I C 1 1Enable PENIRQ-bar rising-edge trigger pulse accumulatorN/A

I C 1 0Disable PENIRQ-bar pulse accumulatorN/A

I R 1Read the number of times PENIRQ-bar has pulsed lowN/A

I 0 1Clear the PENIRQ-bar pulse accumulatorN/A

P R 7Read BUSY-bar pin statusN/A
6.3) 加入到更新后的MINIQUSB+固件中的命令表24. 更新后MINIQUSB+固件01.05.40支持的SPI命令

DEMO1234 CommandActionCPOLCPHACS-Bar ControlAF Length

S C L0Configure SPI for CPOL=00—GPIO-K91 byte

S C L1Configure SPI for CPOL=11—GPIO-K91 byte

S C A0Configure SPI for CPHA=0—0GPIO-K91 byte

S C A1Configure SPI for CPHA=1—1GPIO-K91 byte

S C C0Configure SPI for 8-bit——GPIO-K91 byte

S C C1Configure SPI for 8-bit auto-CS-bar——Automatic1 byte

S C C2Configure SPI for 16-bit auto-CS-bar——Automatic2 bytes

S C C3Configure SPI for 24-bit auto-CS-bar——Automatic3 bytes

S C C4Configure SPI for 32-bit auto-CS-bar——Automatic4 bytes

2 AE 00Configure SPI for 8-bit00GPIO-K91 byte

2 AE 01Configure SPI for 8-bit01GPIO-K91 byte

2 AE 02Configure SPI for 8-bit10GPIO-K91 byte

2 AE 03Configure SPI for 8-bit11GPIO-K91 byte

2 AE 08Configure SPI for 8-bit auto-CS-bar00Automatic1 byte

2 AE 09Configure SPI for 8-bit auto-CS-bar01Automatic1 byte

2 AE 0AConfigure SPI for 8-bit auto-CS-bar10Automatic1 byte

2 AE 0BConfigure SPI for 8-bit auto-CS-bar11Automatic1 byte

2 AE 18Configure SPI for 16-bit auto-CS-bar00Automatic2 bytes

2 AE 19Configure SPI for 16-bit auto-CS-bar01Automatic2 bytes

2 AE 1AConfigure SPI for 16-bit auto-CS-bar10Automatic2 bytes

2 AE 1BConfigure SPI for 16-bit auto-CS-bar11Automatic2 bytes

2 AE 28Configure SPI for 24-bit auto-CS-bar00Automatic3 bytes

2 AE 29Configure SPI for 24-bit auto-CS-bar01Automatic3 bytes

2 AE 2AConfigure SPI for 24-bit auto-CS-bar10Automatic3 bytes

2 AE 2BConfigure SPI for 24-bit auto-CS-bar11Automatic3 bytes

2 AE 38Configure SPI for 32-bit auto-CS-bar00Automatic4 bytes

2 AE 39Configure SPI for 32-bit auto-CS-bar01Automatic4 bytes

2 AE 3AConfigure SPI for 32-bit auto-CS-bar10Automatic4 bytes

2 AE 3BConfigure SPI for 32-bit auto-CS-bar11Automatic4 bytes

2 AF xxPerform an 8-bit SPI transfer (CS-bar = GPIO or auto-CS-bar = 1-byte)———1 byte

3 AF xx xxPerform a 16-bit SPI transfer (requires auto-CS-bar = 2-byte mode)———2 bytes

4 AF xx xx xxPerform a 24-bit SPI transfer (requires auto-CS-bar = 3-byte mode)———3 bytes

5 AF xx xx xx xxPerform a 32-bit SPI transfer (requires auto-CS-bar = 4-byte mode)———4 bytes

2 F9 0Drive CS-bar pin low——GPIO-K9—

2 F9 1Drive CS-bar pin high——GPIO-K9—
表25. 更新后MINIQUSB+固件01.05.41中的中断脉冲累加器命令

DEMO1234 CommandActionIntGPIO Input

Firmware Command

2 C3 00Query which of the C3 commands are supported; the return value is a 2-byte bitmap of commands C300 to C30F, msb first——

C3 00

I Q 0Query configuration of pulse accumulatorINT0GPIO-K5

C3 01 00

I Q 1Query configuration of pulse accumulatorINT1GPIO-K6

C3 01 01

I Q 2Query configuration of pulse accumulatorINT2GPIO-K7

C3 01 02

I Q 3Query configuration of pulse accumulatorINT3GPIO-K8

C3 01 03

I C 0 0Configure pulse accumulator: disable interruptINT0GPIO-K5

C3 02 00 00

I C 1 0Configure pulse accumulator: disable interruptINT1GPIO-K6

C3 02 01 00

I C 2 0Configure pulse accumulator: disable interruptINT2GPIO-K7

C3 02 02 00

I C 3 0Configure pulse accumulator: disable interruptINT3GPIO-K8

C3 02 03 00

I C 0 1Configure pulse accumulator: rising-edge triggerINT0GPIO-K5

C3 02 00 01

I C 1 1Configure pulse accumulator: rising-edge triggerINT1GPIO-K6

C3 02 01 01

I C 2 1Configure pulse accumulator: rising-edge triggerINT2GPIO-K7

C3 02 02 01

I C 3 1Configure pulse accumulator: rising-edge triggerINT3GPIO-K8

C3 02 03 01

I C 0 3Configure pulse accumulator: falling-edge triggerINT0GPIO-K5

C3 02 00 03

I C 1 3Configure pulse accumulator: falling-edge triggerINT1GPIO-K6

C3 02 01 03

I C 2 3Configure pulse accumulator: falling-edge triggerINT2GPIO-K7

C3 02 02 03

I C 3 3Configure pulse accumulator: falling-edge triggerINT3GPIO-K8

C3 02 03 03

I R 0Read pulse accumulatorINT0GPIO-K5

C3 03 00

I R 1Read pulse accumulatorINT1GPIO-K6

C3 03 01

I R 2Read pulse accumulatorINT2GPIO-K7

C3 03 02

I R 3Read pulse accumulatorINT3GPIO-K8

C3 03 03

I 0 0Clear pulse accumulatorINT0GPIO-K5

C3 04 00

I 0 1Clear pulse accumulatorINT1GPIO-K6

C3 04 01

I 0 2Clear pulse accumulatorINT2GPIO-K7

C3 04 02

I 0 3Clear pulse accumulatorINT3GPIO-K8

C3 04 03

I S 0 xxSet pulse accumulator count xx = 0 to 255INT0GPIO-K5

C3 05 00 xx

I S 1 xxSet pulse accumulator count xx = 0 to 255INT1GPIO-K6

C3 05 01 xx

I S 2 xxSet pulse accumulator count xx = 0 to 255INT2GPIO-K7

C3 05 02 xx

I S 3 xxSet pulse accumulator count xx = 0 to 255INT3GPIO-K8

C3 05 03 xx
7) 结论这些实例简要介绍了怎样使用MAX1233/MAX1234的主要功能模块，利用简化的控制台C++程序来测量并控制硬件。如果需要深入了解详细信息，请参考MAX1233/MAX1234数据资料。