TSC2200 TSC220 TSC220 0 0 SBAS191F – FEBRUARY 2001 – REVISED APRIL 2004 PDA ANALOG INTERFACE CIRCUIT FEATURES APPLICATIONS ● 4-WIRE TOUCH SCREEN INTERFACE AND 4-BY-4 KEYPAD INTERFACE ● RATIOMETRIC CONVERSION ● SINGLE 2.7V TO 3.6V SUPPLY ● SERIAL INTERFACE ● INTERNAL DETECTION OF SCREEN TOUCH AND KEYPAD ● PROGRAMMABLE 8-, 10-, OR 12-BIT RESOLUTION ● PROGRAMMABLE SAMPLING RATES ● DIRECT BATTERY MEASUREMENT (0.
ABSOLUTE MAXIMUM RATINGS(1) ELECTROSTATIC DISCHARGE SENSITIVITY VDD to GND ........................................................................ –0.3V to +6.0V VBAT Input Voltage to GND ............................................... –0.3V to +6.0V Analog Input Voltage to GND (except VBAT) ........... –0.3V to VDD + 0.3V Digital Input Voltage to GND ................................... –0.3V to VDD + 0.3V Operating Temperature Range ......................................
ELECTRICAL CHARACTERISTICS At –40°C to +85°C, +VDD = +2.7V, internal VREF = +2.5V, conversion clock = 2MHz, and 12-bit mode, unless otherwise noted. TSC2200IPW PARAMETER CONDITIONS AUXILIARY ANALOG INPUT Input Voltage Range Input Capacitance Input Leakage Current VOLTAGE REFERENCE Voltage Range 0.5 POWER-SUPPLY REQUIREMENTS Power-Supply Voltage, +VDD Quiescent Current MIN +VREF ✻ 6.0 –3 –40 ✻ +3 ✻ +85 ✻ ±2 2.5 1.25 20 1.0 Specified Performance See Note (1) See Note (2) Power-Down 2.
PIN CONFIGURATION 23 MISO VBAT1 7 22 DAV VBAT2 8 21 MOSI VREF 9 20 SS KBIRQ 10 19 SCLK R1 11 18 C4 R2 12 17 C3 R3 13 16 C2 R4 14 15 C1 TSC2200 25 NC 6 1 24 NC Y– 2 23 AOUT GND 3 22 PENIRQ VBAT1 4 21 MISO VBAT2 5 20 DAV VREF 6 19 MOSI KBIRQ 7 18 SS R1 8 17 SCLK TSC2200 16 GND X– C4 PENIRQ 26 ARNG 24 15 5 C3 Y– 27 AUX2 AOUT 14 25 C2 4 28 AUX1 X– 13 ARNG C1 26 29 VDD 3 12 Y+ R4 AUX2 30 VDD 27 11 2 R3 X+ 31
TYPICAL CHARACTERISTICS At TA = +25°C, +VDD = +2.7V, conversion clock = 2MHz, 12-bit mode, and VREF = +2.5V, unless otherwise noted. POWER-DOWN SUPPLY CURRENT vs TEMPERATURE CONVERSION SUPPLY CURRENT vs TEMPERATURE 10 1.86 1.85 8 1.84 IDD (nA) IDD (mA) 1.83 1.82 1.81 1.80 6 4 2 1.79 1.78 0 –60 –40 –20 0 20 40 60 80 100 –40 –20 0 POWER-DOWN SUPPLY CURRENT vs SUPPLY VOLTAGE 8.7 0.25 8.6 0.20 0.15 0.10 60 80 100 8.5 8.4 8.3 8.2 0.05 8.1 0 2.7 2.9 3.1 3.3 2.5 3.7 3.5 2.
TYPICAL CHARACTERISTICS (Cont.) At TA = +25°C, +VDD = +2.7V, conversion clock = 2MHz, 12-bit mode, and VREF = +2.5V, unless otherwise noted. INTERNAL REFERENCE vs VDD 1.275 2.54 1.270 2.54 1.270 1.265 2.53 2.52 1.260 2.52 1.260 2.51 1.255 2.51 1.255 2.50 1.250 1.25V Reference VREF (V) 2.53 2.5V Reference 2.49 1.245 2.50 1.250 2.5V Reference 2.49 2.48 1.240 2.47 1.235 2.47 1.235 2.46 1.230 2.46 1.230 1.225 100 2.45 –40 –20 0 20 40 60 80 1.225 2.5 2.7 2.9 3.
TYPICAL CHARACTERISTICS (Cont.) At TA = +25°C, +VDD = +2.7V, conversion clock = 2MHz, 12-bit mode, and VREF = +2.5V, unless otherwise noted. TEMP1 DIODE VOLTAGE vs SUPPLY VOLTAGE TEMP2 DIODE VOLTAGE vs TEMPERATURE 900 612.0 611.8 611.6 Diode Voltage (mV) Voltage (mV) 800 700 600 611.4 611.2 611.0 610.8 610.6 610.4 610.2 500 –60 610.0 –40 –20 0 20 40 60 80 100 2.5 2.7 2.9 TEMP2 DIODE VOLTAGE vs SUPPLY VOLTAGE 3.3 3.5 3.7 DAC OUTPUT CURRENT vs TEMPERATURE 727.06 1.00 727.04 0.
OVERVIEW Communication to the TSC2200 is via a standard SPI serial interface. This interface requires that the Slave Select signal be driven LOW to communicate with the TSC2200. Data is then shifted into or out of the TSC2200 under control of the host microprocessor, which also provides the serial data clock. The TSC2200 is an analog interface circuit for human interface devices. A register-based architecture eases integration with microprocessor-based systems through a standard SPI bus.
OPERATION—TOUCH SCREEN A resistive touch screen works by applying a voltage across a resistor network and measuring the change in resistance at a given point on the matrix where a screen is touched by an input stylus, pen, or finger. The change in the resistance ratio marks the location on the touch screen. The TSC2200 supports the resistive 4-wire configurations (see Figure 1). The circuit determines location in two coordinate pair dimensions, although a third dimension can be added for measuring pressure.
The TSC2200 touch screen interface can measure position (X and Y) and pressure (Z). Determination of these coordinates is possible under three different modes of the A/D converter: conversion controlled by the TSC2200, initiated by detection of a touch; conversion controlled by the TSC2200, initiated by the host responding to the PENIRQ signal; or conversion completely controlled by the host processor.
A unique configuration of low on-resistance switches allows an unselected A/D converter input channel to provide power and an accompanying pin to provide ground for driving the touch panel. By maintaining a differential input to the converter and a differential reference input architecture, it is possible to negate errors caused by the driver switch onresistances. The A/D converter is controlled by an A/D Converter Control Register.
pulled to ground through the touch screen and PENIRQ output goes LOW due to the current path through the panel to GND, initiating an interrupt to the processor. During the measurement cycles for the X- and Y-positions, the X+ input will be disconnected from the PENIRQ pull-down transistor to eliminate any leakage current from the pull-up resistor to flow through the touch screen, thus causing no errors.
To read all the first page of memory, for example, the host processor must send the TSC2200 the command 8000H—this specifies a read operation beginning at Page 0, Address 0. The processor can then start clocking data out of the TSC2200. The TSC2200 will automatically increment its address pointer to the end of the page; if the host processor continues clocking data out past the end of a page, the TSC2200 will simply send back the value FFFFH.
TSC2200 CONTROL REGISTERS the TSC2200, bits in control registers may refer to slightly different functions depending upon if you are reading the register or writing to it. A summary of all registers and bit locations is shown in Table IV. This section will describe each of the registers that were shown in the memory map of Table III. The registers are grouped according to the function they control.
TSC2200 A/D CONVERTER CONTROL REGISTER (PAGE 1, ADDRESS 00H) The A/D converter in the TSC2200 is shared between all the different functions. A control register determines which input is selected, as well as other options. The result of the conversion is placed in one of the result registers in Page 0 of memory, depending upon the function selected. lifted or the process is stopped. Continuous scans or conversions can be stopped by writing a 1 to this bit.
Bits[7:6]: AV1, AV0—Converter Averaging Control. These two bits allow you to specify the number of averages the converter will perform, as shown in Table X. Note that when averaging is used, the STS bit and the DAV output will indicate that the converter is busy until all conversions necessary for the averaging are complete. The default state for these bits is 00, selecting no averaging. These bits are the same whether reading or writing.
DL1 DL0 0 0 1 1 0 1 0 1 the register(s) updated by the conversion have been read. When all updated data has been read by the host, the DAV pin and this bit will return to a logic 1 (HIGH). DELAY TIME 0µs 100µs 500µs 1000µs DAVB TABLE XVII. Reference Power-Up Delay Settings. VALUE 0 Bit 1: PDN—Reference Power Down. If a 1 is written to this bit, the internal reference will be powered down between conversions. If this bit is a zero, the internal reference will be powered at all times.
KEYPAD CONTROL REGISTER (PAGE 1, ADDRESS 01H) KEYPAD MASK REGISTER (PAGE 1, ADDRESS 10H) The Keypad Control register is formatted as shown in Table XXV. The Keypad Mask register is formatted as shown in Table XXIX. This is the same format as used in the Keypad Data register (Page 0, Address 04H). Each bit in these registers represents one key on the keypad. In the Mask register, if a bit is set (1), then that key will not be detected in keyboard scans.
MSB BIT 15 BIT 14 BIT 13 BIT 12 BIT 11 BIT 10 BIT 9 BIT 8 BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 LSB BIT 0 1 0 1 1 1 0 1 1 X X X X X X X X TABLE XXXI. Reset Register. TSC2200 DATA REGISTERS The data registers of the TSC2200 hold data results from conversions or keypad scans, or the value of the D/A converter output current.
The time needed to get a complete X/Y-coordinate reading can be calculated by: (3) 1 tCOORDINATE = 2.5 µs + 2( tPVS + tPRE + tSNS ) + 2NAVG NBITS • + 4.
Turn On Drivers: Y+, X– Touch Screen Scan X, Y, and Z PENIRQ Initiated No Screen Touch Is Panel Voltage Stabilization Done Yes Turn On Drivers: X+, X– Issue Interrupt PENIRQ Power Up A/D Converter No Is PSM = 1 No Go to Host-Controlled Conversion Is Panel Voltage Stabilization Done Convert Z1-Coordinates Yes Yes No Start Clock Power Up A/D Converter Turn On Drivers: Y+, Y– Convert Y-Coordinates Is Data Averaging Done Yes Store Z1-Coordinates in Z1-Register No Is Panel Voltage Stabilization
Conversion Controlled by TSC2200 Initiated By Host Responding to PENIRQ scan functions. The conversion process then proceeds as described above, and as outlined in Figures 10 through 14. In this mode, the TSC2200 will detect when the touch panel is touched and cause the PENIRQ line to go LOW.
Screen Touch Touch Screen Scan X, Y, and Z Host Initiated Issue Interrupt PENIRQ Turn On Drivers: Y+, X– No No Is PSM = 1 Go to Host-Controlled Conversion Turn On Drivers: X+, X– Is Panel Voltage Stabilization Done Yes Power Up A/D Converter Done No Host Writes A/D Converter Control Register Is Panel Voltage Stabilization Done Convert Z1-Coordinates Yes Reset PENIRQ Power Up A/D Converter No Is Data Averaging Done Start Clock Convert Y-Coordinates Yes Store Z1-Coordinates in Z1-Register T
Screen Touch Touch Screen Scan X-Coordinate Host Initiated Issue Interrupt PENIRQ No Is PSM = 1 Go to Host-Controlled Conversion Convert X-Coordinates Done No Host Writes A/D Converter Control Register Is Data Averaging Done Yes Reset PENIRQ Store X-Coordinates in X-Register No Start Clock Are Drivers On Yes Turn On Drivers: Y+, Y– Power Down A/D Converter Issue Data Available Turn Off Clock Start Clock No Is Panel Voltage Stabilization Done Done Yes Power Up A/D Converter FIGURE 12.
Screen Touch Touch Screen Scan Y-Coordinate Host Initiated Issue Interrupt PENIRQ No Is PSM = 1 Go to Host-Controlled Conversion Store Y-Coordinates in Y-Register Done Power Down A/D Converter Host Writes A/D Converter Control Register Issue Data Available Reset PENIRQ Turn Off Clock Are Drivers On Done No Start Clock Yes Turn On Drivers: X+, X– Start Clock No Power Up A/D Converter Is Panel Voltage Stabilization Done Yes Convert Y-Coordinates No Is Data Averaging Done Yes FIGURE 13.
Screen Touch Touch Screen Scan Z-Coordinate Host Initiated Issue Interrupt PENIRQ No Is PSM = 1 Go to Host-Controlled Conversion Convert Z2-Coordinates Done Host Writes A/D Converter Control Register No Reset PENIRQ Are Drivers On Is Data Averaging Done Yes Store Z2-Coordinates in Z2-Register No Start Clock Power Down A/D Converter Turn On Drivers: Y+, X– Yes Issue Data Available Start Clock No Is Panel Voltage Stabilization Done Yes Power Up A/D Converter Turn Off Clock Done Convert Z1-C
Conversion Controlled by the Host In this mode, the TSC2200 will detect when the touch panel is touched and cause the PENIRQ line to go LOW. The host will recognize the interrupt request. Instead of starting a sequence in the TSC2200 which then reads each coordinate in turn, the host now must control all aspects of the conversion. Generally, upon receiving the interrupt request, the host will turn on the Y-drivers.
Host-Controlled Y-Coordinate Screen Touch Host Writes A/D Converter Control Register Issue Interrupt PENIRQ No Start Clock No Is PSM = 1 Go to Host-Controlled Conversion Are Drivers On Yes Turn On Drivers: X+, X– Start Clock Done Host Writes A/D Converter Control Register Is Panel Voltage Stabilization Done Yes Power Up A/D Converter Convert Y-Coordinate No Reset PENIRQ Turn On Drivers: X+, X– No Done Is Data Averaging Done Yes Store Y-Coordinates in Y-Register Power Down A/D Converter
Screen Touch Host-Controlled Z-Coordinate Issue Interrupt PENIRQ No Is PSM = 1 Convert Z2-Coordinates Go to Host-Controlled Conversion Done No Host Writes A/D Converter Control Register Is Data Averaging Done Yes Reset PENIRQ Store Z2-Coordinates in Z2-Register Turn On Drivers: Y+, X– Power Down A/D Converter Done Issue Data Available Host Writes A/D Converter Control Register Turn Off Clock Reset PENIRQ Done Is Data Averaging Done No Start Clock Turn On Drivers: Y+, X– Yes Start Clock No I
OPERATION—TEMPERATURE MEASUREMENT Host Writes A/D Converter Control Register In some applications, such as battery recharging, a measurement of ambient temperature is required. The temperature measurement technique used in the TSC2200 relies on the characteristics of a semiconductor junction operating at a fixed current level. The forward diode voltage (VBE) has a well-defined characteristic versus temperature.
OPERATION—BATTERY MEASUREMENT Host Writes A/D Converter Control Register An added feature of the TSC2200 is the ability to monitor the battery voltage on the other side of a voltage regulator (DC/DC converter), as shown in Figure 21. The battery voltage can vary from 0.5V to 6V while maintaining the voltage to the TSC2200 at 2.7V, 3.3V, etc. The input voltage (VBAT1 or VBAT2 ) is divided down by 4 so that a 6.0V battery voltage is represented as 1.5V to the A/D converter.
OPERATION—AUXILIARY MEASUREMENT OPERATION—PORT SCAN The two auxiliary voltage inputs can be measured in much the same way as the battery inputs, as shown in Figures 24 and 25. Applications might include external temperature sensing, ambient light monitoring for controlling the backlight, or sensing the current drawn from the battery. If making measurements of all the analog inputs (except the touch screen) is desired on a periodic basis, the Port Scan mode can be used.
OPERATION—D/A CONVERTER 0.9 The TSC2200 has an onboard 8-bit D/A converter, configured as shown in Figure 27. This configuration yields a current sink (AOUT) controlled by the value of a resistor connected between the ARNG pin and ground. The D/A converter has a control register that controls whether or not the converter is powered up. The 8-bit data is written to the D/A converter through the D/A converter data register. IOUT (Full-Scale) (mA) 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.
In the previous example, when the D/A converter current is zero, the voltage on the AOUT pin will rise above the TSC2200 supply voltage. This is not a problem, however, since V+ was within the absolute maximum ratings of the TSC2200, so no special precautions are necessary. Many LCD displays require voltages much higher than the absolute maximum ratings of the TSC2200. In this case, the addition of an NPN transistor, as shown in Figure 29, will protect the AOUT pin from damage.
LAYOUT The following layout suggestions should provide optimum performance from the TSC2200. However, many portable applications have conflicting requirements concerning power, cost, size, and weight. In general, most portable devices have fairly “clean” power and grounds because most of the internal components are very low power. This situation would mean less bypassing for the converter’s power and less concern regarding grounding.
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PACKAGE OPTION ADDENDUM www.ti.com (4) 27-Jul-2013 There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device. (5) Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation of the previous line and the two combined represent the entire Device Marking for that device.
PACKAGE MATERIALS INFORMATION www.ti.com 27-Jul-2013 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant TSC2200IPWR TSSOP PW 28 2000 330.0 16.4 6.9 10.2 1.8 12.0 16.0 Q1 TSC2200IRHBR VQFN RHB 32 3000 330.0 12.4 5.3 5.3 1.5 8.0 12.
PACKAGE MATERIALS INFORMATION www.ti.com 27-Jul-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) TSC2200IPWR TSC2200IRHBR TSSOP PW 28 2000 367.0 367.0 38.0 VQFN RHB 32 3000 338.1 338.1 20.
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