TSC2005 SBAS379C – DECEMBER 2006 – REVISED MARCH 2008 1.6V to 3.6V, 12-Bit, Nanopower, 4-Wire TOUCH SCREEN CONTROLLER with SPI™ Interface FEATURES APPLICATIONS • • • • • • • • • • • • • 1 23 • • • • • • 4-Wire Touch Screen Interface Ratiometric Conversion Single 1.6V to 3.
TSC2005 www.ti.com SBAS379C – DECEMBER 2006 – REVISED MARCH 2008 This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage. ESD damage can range from subtle performance degradation to complete device failure.
TSC2005 www.ti.com SBAS379C – DECEMBER 2006 – REVISED MARCH 2008 ELECTRICAL CHARACTERISTICS At TA = –40°C to +85°C, SNSVDD = VREF = +1.6V to +3.6V, I/OVDD = +1.2V to +3.6V, unless otherwise noted.
TSC2005 www.ti.com SBAS379C – DECEMBER 2006 – REVISED MARCH 2008 ELECTRICAL CHARACTERISTICS (continued) At TA = –40°C to +85°C, SNSVDD = VREF = +1.6V to +3.6V, I/OVDD = +1.2V to +3.6V, unless otherwise noted. TSC2005 PARAMETER TEST CONDITIONS MIN TYP MAX UNIT DIGITAL INPUT/OUTPUT Logic family CMOS VIH VIL Logic level IIL 1.2V ≤ I/OVDD < 1.6V 0.7 × I/OVDD I/OVDD + 0.3 V 1.6V ≤ I/OVDD ≤ 3.6V 0.7 × I/OVDD I/OVDD + 0.3 V 1.2V ≤ I/OVDD < 1.6V –0.3 0.2 × I/OVDD V 1.6V ≤ I/OVDD ≤ 3.6V –0.
TSC2005 www.ti.com SBAS379C – DECEMBER 2006 – REVISED MARCH 2008 PIN CONFIGURATION YZL PACKAGE WCSP-18 (TOP VIEW, SOLDER BUMPS ON BOTTOM SIDE) AGND VREF X+ Y+ SUBGND AUX NC NC NC X- I/OVDD NC NC NC Y- DGND NC NC NC NC SNSGND SDI SCLK SDO CS D E F SNSVDD 5 Rows 4 3 2 RESET PINTDAV 1 A B C Columns (FRONT VIEW) PIN ASSIGNMENTS PIN NO.
TSC2005 www.ti.com SBAS379C – DECEMBER 2006 – REVISED MARCH 2008 TIMING INFORMATION The TSC2005 supports SPI programming in mode CPOL = 0 and CPHA = 0. The falling edge of SCLK is used to change output (MISO) data and the rising edge is used to latch input (MOSI) data. Eight SCLKs are required to complete the Byte 1 command cycle, and 24 SCLKs are required for the Byte 0 command cycle.
TSC2005 www.ti.com SBAS379C – DECEMBER 2006 – REVISED MARCH 2008 TYPICAL CHARACTERISTICS At TA = –40°C to +85°C, SNSVDD = VREF = +1.6V to +3.6V, I/OVDD = +1.2V to +3.6V, fADC = fOSC/2, fSCLK = 10MHz, 12-bit mode, and non-continuous AUX measurement, unless otherwise noted. SUPPLY CURRENT vs TEMPERATURE SUPPLY CURRENT vs TEMPERATURE 40 I/OVDD = SNSVDD = 3V VREF = 2.
TSC2005 www.ti.com SBAS379C – DECEMBER 2006 – REVISED MARCH 2008 TYPICAL CHARACTERISTICS (continued) At TA = –40°C to +85°C, SNSVDD = VREF = +1.6V to +3.6V, I/OVDD = +1.2V to +3.6V, fADC = fOSC/2, fSCLK = 10MHz, 12-bit mode, and non-continuous AUX measurement, unless otherwise noted. CHANGE IN GAIN vs TEMPERATURE 0.6 6 I/OVDD = SNSVDD = 3V VREF = 2.5V 0.2 0 -0.2 -0.4 -20 0 60 20 40 Temperature (°C) 80 -2 100 -40 -20 20 40 Temperature (°C) 60 80 Figure 9.
TSC2005 www.ti.com SBAS379C – DECEMBER 2006 – REVISED MARCH 2008 TYPICAL CHARACTERISTICS (continued) At TA = –40°C to +85°C, SNSVDD = VREF = +1.6V to +3.6V, I/OVDD = +1.2V to +3.6V, fADC = fOSC/2, fSCLK = 10MHz, 12-bit mode, and non-continuous AUX measurement, unless otherwise noted. TEMP DIODE VOLTAGE vs TEMPERATURE Measurement Includes A/D Converter Offset and Gain Errors TEMP Diode Voltage (mV) 800 95.2mV 750 TEMP2 700 650 600 TEMP1 550 138.
TSC2005 www.ti.com SBAS379C – DECEMBER 2006 – REVISED MARCH 2008 OVERVIEW The TSC2005 is an analog interface circuit for a human interface touch screen device. A register-based architecture eases integration with microprocessor-based systems through a standard SPI bus. All peripheral functions are controlled through the registers and onboard state machines.
TSC2005 www.ti.com SBAS379C – DECEMBER 2006 – REVISED MARCH 2008 TOUCH SCREEN OPERATION A resistive touch screen operates by applying a voltage across a resistor network and measuring the change in resistance at a given point on the matrix where the screen is touched by an input (stylus, pen, or finger). The change in the resistance ratio marks the location on the touch screen. The TSC2005 supports the resistive 4-wire configurations, as shown in Figure 21.
TSC2005 www.ti.com SBAS379C – DECEMBER 2006 – REVISED MARCH 2008 Measure X-Position X+ Y+ Touch X-Position Y- X- Measure Z1-Position Y+ X+ Touch Z1-Position Y- X- Y+ X+ Touch Z2-Position X- YMeasure Z2-Position Figure 22. Pressure Measurement When the touch panel is pressed or touched and the drivers to the panel are turned on, the voltage across the touch panel often overshoots and then slowly settles down (decays) to a stable dc value.
TSC2005 www.ti.com SBAS379C – DECEMBER 2006 – REVISED MARCH 2008 INTERNAL TEMPERATURE SENSOR In some applications, such as battery recharging, an ambient temperature measurement is required. The temperature measurement technique used in the TSC2005 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.
TSC2005 www.ti.com SBAS379C – DECEMBER 2006 – REVISED MARCH 2008 ANALOG-TO-DIGITAL CONVERTER Figure 24 shows the analog inputs of the TSC2005. The analog inputs (X, Y, and Z touch panel coordinates, chip temperature and auxiliary inputs) are provided via a multiplexer to the Successive Approximation Register (SAR) Analog-to-Digital (A/D) converter. The A/D architecture is based on capacitive redistribution architecture, which inherently includes a sample-and-hold function.
TSC2005 www.ti.com SBAS379C – DECEMBER 2006 – REVISED MARCH 2008 Data Format The TSC2005 output data is in Straight Binary format as shown in Figure 25. This figure shows the ideal output code for the given input voltage and does not include the effects of offset, gain, or noise. FS = Full-Scale Voltage = VREF(1) 1LSB = VREF(1)/4096 1LSB 11...111 Output Code 11...110 11...101 00...010 00...001 00...000 0V Input Voltage (2) FS - 1LSB (V) (1) Reference voltage at converter: +REF – (–REF).
TSC2005 www.ti.com SBAS379C – DECEMBER 2006 – REVISED MARCH 2008 Touch Detect PINTDAV can be programmed to generate an interrupt to the host. Figure 26 details an example for the Y-position measurement. While in the power-down mode, the Y– driver is on and connected to GND. The internal pen-touch signal depends on whether or not the X+ input is driven low.
TSC2005 www.ti.com SBAS379C – DECEMBER 2006 – REVISED MARCH 2008 Preprocessing The TSC2005 offers an array of powerful preprocessing operations that reduce unnecessary traffic on the bus and reduce host processor loading. This reduction is especially critical for the serial interface, where limited bandwidth is a tradeoff, keeping the connection lines to a minimum. All data acquisition tasks are looking for specific data that meet certain criteria.
TSC2005 www.ti.com SBAS379C – DECEMBER 2006 – REVISED MARCH 2008 NOTE: The default setting for MAVF is MVF (median value filter with averaging bypassed) for any invalid configuration. For example, if (M1, M0, W1, W0) = (1,0,1,0), the MAVF performs as it was configured for (1,0,0,0), median filter only with filter size = 7 and no averaging. The only exception is M > 1 and (W1, W0) = (1,1). This setting is reserved and should not be used. Table 3.
TSC2005 www.ti.com SBAS379C – DECEMBER 2006 – REVISED MARCH 2008 DIGITAL INTERFACE The TSC2005 communicates through a standard SPI bus. The SPI allows full-duplex, synchronous, serial communication between a host processor (the master) and peripheral devices (slaves). The SPI master generates the synchronizing clock and initiates transmissions. The SPI slave devices depend on a master to start and synchronize transmissions. A transmission begins when initiated by a master SPI.
TSC2005 www.ti.com SBAS379C – DECEMBER 2006 – REVISED MARCH 2008 Table 7. Converter Function Select C3 C2 C1 C0 FUNCTION 0 0 0 0 Touch screen scan function: X, Y, Z1, and Z2 coordinates converted and the results returned to X, Y, Z1, and Z2 data registers. Scan continues until either the pen is lifted or a stop bit is sent. 0 0 0 1 Touch screen scan function: X and Y coordinates converted and the results returned to X and Y data registers.
TSC2005 www.ti.com SBAS379C – DECEMBER 2006 – REVISED MARCH 2008 Touch Sensor Short-Circuit Test If the TBM bits of CFR1 detailed in Table 20 are all set to '1', a short-circuit in the touch sensor can be detected. C3-C0 = 1011: PINTDAV = 0 during this short-circuit test. A '1' shown at end of the test indicates there is no short-circuit detected (through X-axis) between the flex and stable layers. If there is a short-circuit detected, PINTDAV stays low until a stop bit (STS set to '1') is issued.
TSC2005 www.ti.com SBAS379C – DECEMBER 2006 – REVISED MARCH 2008 Table 10.
TSC2005 www.ti.com SBAS379C – DECEMBER 2006 – REVISED MARCH 2008 REGISTER ACCESS (Control Byte 0 with R/W Bit) Control byte 0, beginning with D7 = 0, is used to access the internal registers. This control byte uses the last bit, D0, to control the flow of data. If D0 is '1', then the content of the register pointed by the address bits (A3-A0) is output to SDO (MISO) in the next cycle.
TSC2005 www.ti.com SBAS379C – DECEMBER 2006 – REVISED MARCH 2008 COMMUNICATION PROTOCOL The TSC2005 is controlled entirely by registers. Reading and writing to these registers are accomplished by the use of Control Byte 0, which includes a 4-bit address plus one read/write TSC register control bit. The data registers defined in Table 10 are all 16-bit, right-adjusted.
TSC2005 www.ti.com SBAS379C – DECEMBER 2006 – REVISED MARCH 2008 CL1, CL0—Conversion clock control. These two bits specify the clock rate that the A/D converter uses to perform conversion, as shown in Table 15. These bits are the same whether reading or writing. Table 15. A/D Converter Conversion Clock Control CL1 CL0 FUNCTION 0 0 fADC = fOSC/1. This is referred to as the 4MHz A/D converter clock rate, 10-bit resolution only. 0 1 fADC = fOSC/2.
TSC2005 www.ti.com SBAS379C – DECEMBER 2006 – REVISED MARCH 2008 Table 18. Sense Time Selection SNS2 SNS1 SNS0 SENSE TIME (tSNS) 0 0 0 32µs 0 0 1 96µs 0 1 0 544µs 0 1 1 608µs 1 0 0 2.080ms 1 0 1 2.144ms 1 1 0 2.592ms 1 1 1 2.656ms DTW—Detection of pen touch in wait (patent pending). Writing a '1' to this bit enables the pen touch detection in background while waiting for the host to issue the converter function in host-initiated/controlled modes.
TSC2005 www.ti.com SBAS379C – DECEMBER 2006 – REVISED MARCH 2008 BTD2-BTD0—Batch Time Delay mode. These are the selection bits that specify the delay before a sample/conversion scan cycle is triggered. When it is set, Batch Time Delay mode uses a set of timers to automatically trigger a sequence of sample-and-conversion events. The mode works for both TSC-initiated scans (XYZ or XY) and host-initiated scans (XYZ or XY).
TSC2005 www.ti.com SBAS379C – DECEMBER 2006 – REVISED MARCH 2008 Configuration Register 2 Configuration register 2 (CFR2) defines the preprocessor configuration. Table 22. Configuration Register 2 (Reset Value = 0000h) MSB D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 LSB D0 PINTS1 PINTS0 M1 M0 W1 W0 TZ1 TZ0 AZ1 AZ0 Resrvd MAVE X MAVE Y MAVE Z MAVE AUX MAVE TEMP PINTS1 (default 0)—This bit controls the output format of the PINTDAV pin.
TSC2005 www.ti.com SBAS379C – DECEMBER 2006 – REVISED MARCH 2008 Converter Function Select Register The Converter Function Select (CFN) register reflects the converter function select status. Table 25. Converter Function Select Status Register (Reset Value = 0000h) MSB D15 D14 D13 D12 D11 D9 D8 D7 D6 D5 D4 D3 D2 D1 LSB D0 CFN9 CFN8 CFN7 CFN6 CFN5 CFN4 CFN3 CFN2 CFN1 CFN0 D10 CFN15 CFN14 CFN13 CFN12 CFN11 CFN10 CFN15-CFN0—Converter function select status.
TSC2005 www.ti.com SBAS379C – DECEMBER 2006 – REVISED MARCH 2008 DATA REGISTERS The data registers of the TSC2005 hold data results from conversions. All data registers default to 0000h upon device reset. X, Y, Z1, Z2, AUX, TEMP1 and TEMP2 REGISTERS The results of all A/D conversions are placed in the appropriate data registers, as described in Table 10. The data format of the result word (R) of these registers is right-justified, as shown in Table 29: Table 29.
TSC2005 www.ti.com SBAS379C – DECEMBER 2006 – REVISED MARCH 2008 REGISTER RESET There are three way to reset the TSC2005. First, at power-on, a power good signal will generate a prolonged reset pulse internally to all registers. Second, an external pin, RESET, is available to perform a system reset or allow other peripherals (such as a display) to reset the device if the pulse meets the timing requirement (at least 10µs wide). Any RESET pulse less than 5µs is rejected.
TSC2005 www.ti.com SBAS379C – DECEMBER 2006 – REVISED MARCH 2008 THEORY OF OPERATION TOUCH SCREEN MEASUREMENTS As noted previously in the discussion of the A/D converter, several operating modes can be used that allow great flexibility for the host processor. This section examines these different modes. Conversion Controlled by TSC2005 Initiated by TSC2005 (TSMode 1) In TSMode 1, before a pen touch can be detected, the TSC2005 must be programmed with PSM = 1 and one of two scan modes: 1.
TSC2005 www.ti.com SBAS379C – DECEMBER 2006 – REVISED MARCH 2008 Table 31.
TSC2005 www.ti.com SBAS379C – DECEMBER 2006 – REVISED MARCH 2008 If the pressure of the touch is also to be measured, the process continues in the same way, but measuring the Z1 and Z2 values instead, and storing the results in temporary registers. Once the complete sample set of data (X, Y, Z1, and Z2) are available, they are loaded in the X, Y, Z1, and Z2 registers. This process is illustrated in Figure 33. As before, this process time depends upon the settings previously described.
TSC2005 www.ti.com SBAS379C – DECEMBER 2006 – REVISED MARCH 2008 Conversion Controlled by TSC2005 Initiated by Host (TSMode 2) In TSMode 2, the TSC2005 detects when the touch panel is touched and causes the internal Pen-Touch signal to activate, which lowers the PINTDAV output if it is programmed as PENIRQ. The host recognizes the interrupt request, and then writes to the A/D Converter Control register to select one of the two touch screen scan functions: 1.
TSC2005 www.ti.com SBAS379C – DECEMBER 2006 – REVISED MARCH 2008 Conversion Controlled by Host (TSMode 3) In TSMode 3, the TSC2005 detects when the touch panel is touched and causes the internal Pen-Touch signal to be active, which lowers the PINTDAV output if it is programmed as PENIRQ. The host recognizes the interrupt request. Instead of starting a sequence in the TSC2005, which then reads each coordinate in turn, the host must now control all aspects of the conversion.
TSC2005 www.ti.
TSC2005 www.ti.
TSC2005 www.ti.com SBAS379C – DECEMBER 2006 – REVISED MARCH 2008 AUXILIARY AND TEMPERATURE MEASUREMENT The TSC2005 can measure the voltage from the auxiliary input (AUX) and from the internal temperature sensor. Applications for the AUX can include external temperature sensing, ambient light monitoring for controlling backlighting, or sensing the current drawn from batteries. There are two converter functions that can be used for the measurement of the AUX: 1.
TSC2005 www.ti.com SBAS379C – DECEMBER 2006 – REVISED MARCH 2008 LAYOUT The following layout suggestions should obtain optimum performance from the TSC2005. However, many portable applications have conflicting requirements for 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 power and less concern regarding grounding.
TSC2005 www.ti.com SBAS379C – DECEMBER 2006 – REVISED MARCH 2008 REVISION HISTORY NOTE: Page numbers for previous revisions may differ from page numbers in the current version. Changes from Revision B (December 2007) to Revision C ........................................................................................... Page • • • • • • • Changed resistance ratio from 80 to 91 ..............................................................................................................................
PACKAGE OPTION ADDENDUM www.ti.
PACKAGE MATERIALS INFORMATION www.ti.com 22-Sep-2011 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) TSC2005IYZLR DSBGA YZL 28 3000 180.0 8.4 TSC2005IYZLT DSBGA YZL 28 250 180.0 8.4 Pack Materials-Page 1 B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant 2.75 3.25 0.81 4.0 8.0 Q1 2.75 3.25 0.81 4.0 8.
PACKAGE MATERIALS INFORMATION www.ti.com 22-Sep-2011 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) TSC2005IYZLR DSBGA YZL 28 3000 210.0 185.0 35.0 TSC2005IYZLT DSBGA YZL 28 250 210.0 185.0 35.
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