MPR121_10 FREESCALE [Freescale Semiconductor, Inc], MPR121_10 Datasheet
MPR121_10
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MPR121_10 Summary of contents
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Freescale Semiconductor Technical Data An Energy Efficient Solution by Freescale Advanced Information Proximity Capacitive Touch Sensor Controller MPR121 OVERVIEW The MPR121 is the second generation sensor controller after the initial release of the MPR03x series devices. The MPR121 will feature ...
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PIN DESCRIPTION Pin No MPR121 2 Pin Description Pin Name Description IRQ Open Collector Interrupt pin 2 SCL I C ...
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SCHEMATIC DRAWINGS AND IMPLEMENTATION VDD 1. 2.75 V Figure 1. Configuration 1: MPR121 runs from a 1. 2.75 V supply. VDD 2 3.6 V Figure 2. Configuration 2: MPR121 runs from a 2.5 V ...
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Touch Sensing Once the capacitance is determined at any given moment, this information must then be translated into intelligent touch recognition. The MPR121 has a couple of systems that have improved over the previous generation in the MPR03x series devices. ...
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Table 1. Register Map REGISTER ELE0 - ELE7 Touch Status ELE7 ELE8 - ELE11, ELEPROX Touch Status OVCF ELE0-7 OOR Status ELE7 ELE8-11, ELEPROX OOR Status ARFF ELE0 Electrode Filtered Data LSB ELE0 Electrode Filtered Data MSB ELE1 Electrode Filtered ...
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Table 1. Register Map REGISTER NCL Falling FDL Falling NHD Amount Touched NCL Touched FDL Touched ELEPROX MHD Rising ELEPROX NHD Amount Rising ELEPROX NCL Rising ELEPROX FDL Rising ELEPROX MHD Falling ELEPROX NHD Amount Falling ELEPROX NCL Falling ELEPROX ...
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Table 1. Register Map REGISTER ELE3 Electrode Current ELE4 Electrode Current ELE5 Electrode Current ELE6 Electrode Current ELE7 Electrode Current ELE8 Electrode Current ELE9 Electrode Current ELE10 Electrode Current ELE11 Electrode Current ELEPROX Electrode Current ELE0, ELE1 Charge Time ELE2, ...
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ELECTRICAL CHARACTERISTICS Absolute Maximum Ratings Absolute maximum ratings are stress ratings only, and functional operation at the maxima is not guaranteed. Stress beyond the limits specified in Table 2 may affect device reliability or cause permanent damage to the device. ...
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DC CHARACTERISTICS This section includes information about power supply requirements and I/O pin characteristics. Table 4. DC Characteristics (Typical Operating Circuit, V and V DD REG Parameter Symbol High Supply Voltage V DD Low Supply Voltage V REG Average Supply ...
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CHARACTERISTICS 2 Table Characteristics (Typical Operating Circuit, and V V REG DD Parameter Serial Clock Frequency Bus Free Time Between a STOP and a START Condition Hold Time, (Repeated) START Condition Repeated ...
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AN3889: MPR121 Capacitance Sensing Settings INTRODUCTION Touch acquisition takes a few different parts of the system in order to detect touch. The first stage of this process is to capture the pad capacitance. Freescale’s MPR121 utilizes the principle that a ...
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V Electrode Charge Time Figure 4. MPR121 Electrode Measurement Charging Pad Capacitance When measuring capacitance there are some inherent restrictions due to the methodology used. On the MPR121 the voltage after charging must be in the range that is shown ...
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Any ADC counts outside of the range shown are invalid and settings must be adjusted to be within this range. If capacitance variation is of importance for an application after the current output, charge time and supply voltage are determined ...
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Sensitivity vs. Capacitance for 1.8 V and I =36 μA and μS 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0. CONFIGURATION From the implementation above, there are two elements ...
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FILTER CONFIGURATION REGISTER 7 R CDT W Reset Unimplemented Table 10. Filter Configuration Register Field Descriptions Field 7:5 Charge Discharge Time – The Charge Discharge Time field selects the amount of CDT time an electrode charges and discharges. ...
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ELECTRODE CHARGE TIME Reset Unimplemented Table 12. Electrode Charge Time Register Field Descriptions Field 6:4 Electrode # Charge Discharge Time – The Charge Discharge Time field selects the CDT# amount of time an electrode ...
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AUTO-CONFIG USL REGISTER Reset Unimplemented Table 14. AUTO-CONFIG USL Register Field Descriptions Field 7:0 Upper Limit – The Upper Limit for the auto-configuration baseline search is set to USL this value. 00000000 – Upper Limit ...
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Table 15. AUTO-CONFIG Target Level Register Field Descriptions Field 7:0 Target Level – The Target Level for the auto-configuration baseline search is set to TL this value. 00000000 – Target Level set to 0 00000001 – Target Level set to ...
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Table 17. AUTO-CONFIG Control Register Field Descriptions Field 7:6 First Filter Iterations – The first filter iterations field selects the number of samples taken AFES as input to the first level of filtering. This value must match the FFI set ...
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Table 18. ELE0-7 Out Of Range Status Register Field Descriptions Field 7 Electrode 7 OOR Status – The Electrode 7 OOR Status shows if the AUTO-CONFIG has failed. E7S 0 – Auto-configuration Successful 1 – Auto-configuration Failed 6 Electrode 6 ...
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ELE8-11, ELEPROX OUT OF RANGE STATUS REGISTER ARFF ACFF W Reset Unimplemented Figure 17. ELE8-11, ELEPROX Out Of Range Status Register Table 19. ELE8-11, ELEPROX Out Of Range Status Register Field Descriptions Field Automatic ...
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AN3890: MPR121 Capacitance Sensing — Filtering and Timing INTRODUCTION The capacitance sensing front end of the MPR121 produces data at extremely high rates, which significantly improves the capabilities of a filtering system. The capacitance engine described in AN3889 act on ...
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Table 20. AFE Configuration Register Field Descriptions Field 7:6 First Filter Iterations – The first filter iterations field selects the number of samples FFI taken as input to the first level of filtering. 00 Encoding 0 – Sets samples taken ...
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Table 21. Filter Configuration Register Field Descriptions Field 7:5 Charge Discharge Time – The Charge Discharge Time field selects the amount of CDT time an electrode charges and discharges. 000 Encoding 0 – Invalid 001 Encoding 1 – Time is ...
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The output data is the Filtered Data High and Low is the data coming out of the second stage filter. This means that the response time of the output is the SFI ...
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AN3891: MPR121 Baseline System INTRODUCTION Touch acquisition takes a few different parts of the system in order to detect touch. The baseline filter and touch detection are tightly coupled. The purpose of the baseline filter is to “filter out touches” ...
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NOISE HALF DELTA (NHD Reset Unimplemented Table 23. Noise Half Delta Register Field Descriptions Field 5:0 Noise Half Delta – The Noise Half Delta determines the incremental change when NHD non-noise drift is detected. ...
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FILTER DELAY LIMIT (FDL Reset Unimplemented Table 25. Filter Delay Limit Register Field Descriptions Field 7:0 Filter Delay Limit – The Filter Delay Limit determines the rate of operation of the FDL filter. A larger ...
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Case 2 Changes that are larger than double the MHD are regarded as noise and accounted for by the values of the NHD and NCL. Any data outside the MHD is rejected by the filter however sequential values that fall ...
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After this averaging the filter reacts to Cases 1, 2, and 3. MHD = 1 NCL = 3 Case 1 NHD = 1 FDL = 4 1 ADVANCED CASES With an understanding of the basic cases, more advanced cases can ...
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Case 6 The system needs the capability to handle environment changes that appear very similar to actual touches. In Case 5, the touch was a real touch, but slow enough that initially it is thought better for the baseline not ...
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Case 8 This case can also prevent keys from being stuck due to misuse. For example metal pen touches a button, this may initially engage the button but the pen is calibrated out over time and, normal function ...
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AN3892: MPR121 Jitter and False Touch Detection INTRODUCTION Touch acquisition takes a few different parts of the system in order to detect touch. The baseline filter and touch detection are tightly coupled. The purpose of the touch detection block is ...
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TOUCH STATUS REGISTER E7S W Reset Unimplemented Table 26. Touch Status Register 0 Field Descriptions Field 7 Electrode 7 Status – The Electrode 7 Status bit shows touched or not touched. E7S 0 – ...
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TOUCH STATUS REGISTER OVCF W Reset Unimplemented Table 27. Touch Status Register 1 Field Descriptions Field 7 Over Current Flag – The Over Current Flag will be set any time the wrong value of OVCF ...
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FILTERED DATA LOW Reset Unimplemented Table 29. Filtered Data Low Register Field Descriptions Field 7:0 Filtered Data Low Byte – The Filtered Data Low Byte displays the lower 8 bits of FDLB the 10 bit ...
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TOUCH THRESHOLD REGISTER Reset Unimplemented Table 31. Touch Threshold Register Field Descriptions Field 7:0 Touch Threshold – The Touch Threshold Byte sets the trip point for detecting a TTH touch. 00000000 Encoding 0 ~ 11111111 ...
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For the system to recognize a touch the delta must be greater than the Touch Threshold. A release is triggered when the Delta falls below the Release Threshold. This can happen for both changes to the Baseline and actual Data ...
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AN3893: MPR121 Proximity Detection INTRODUCTION MPR121 is a feature rich, second generation touch sensor controller after Freescale’s initial release of the MPR03x series device. Like MPR03x, MPR121 has a unique feature that all the electrode inputs can be internally connected ...
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Eleprox Baseline Value Register (0x2A) contains the 8 MSBs of the 10-bit baseline value for the 13 electrode. Writing to Baseline Value Register updates the 8 MSBs of baseline value and clears the 2 LSBs to zero. The Baseline Value ...
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Proximity Baseline Filter Setting As with the touch detection, the proximity detection also dedicates register sets for baseline filter control. These include the maximum half delta for rising/falling, the noise half delta for rising/falling/touched, the noise count limit for ...
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AFE and Filter Configuration Register The last two registers relevant to proximity detection are the AFE Configuration Register and Filter Configuration Register. These two registers set the numbers of samples for the 2 level filters and the sampling interval ...
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AN3894: MPR121 GPIO and LED Driver Function INTRODUCTION MPR121 is a feature rich second generation touch sensor controller after Freescale’s initial release of the MPR03x series de- vice. MPR121 not only has priority unique features like independent electrode auto configuration ...
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VDD 2 3.6 V Figure 47. Configuration 2: MPR121 runs from a 2 3.6 V supply. These registers control GPIO function. D7~D0 bits corresponds GPIO7~GPIO0 pins respectively. The GPIO control registers can write always regardless Shutdown ...
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The GPIO system allows the GPIO pins to be set as input or output. When an EN bit sets, the corresponding GPIO pin is enabled and the function is configured by CTL0, CTL1 and DIR bits. When the port is ...
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PWM0[3:0] ~ PWM7[3:0] is used to set the PWM duty of GPIO0 ~ GPIO7 respectively. The power up reset default setting for these four register is 0x00. When a GPIO is programmed as output and the DAT register is “1” ...
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AN3895: MPR121 Serial Communication INTRODUCTION 2 The MPR121 uses Serial Interface. The I Sensor Controller are detailed in this application note. SERIAL-ADDRESSING The MPR121 operates as a slave that sends and receives data through an I Data ...
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BIT TRANSFER One data bit is transferred during each clock pulse SDA SCL S START CONDITION ACKNOWLEDGE th The acknowledge bit is a clocked 9 bit each byte transferred effectively requires 9 bits. The master generates the 9 during the ...
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MESSAGE FORMAT FOR WRITING THE MPR121 A write to the MPR121 comprises the transmission of the MPR121’s keyscan slave address with the R/W bit set to 0, followed by at least one byte of information. The first byte of information ...
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AN3944: MPR121 Quick Start Guide INTRODUCTION The MPR121 is Freescale Semiconductor’s top of the line touch sensor and can fit into a wide range of applications. These applications can all be accommodated by having a device a with a very ...
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Register Address 0x7D AUTO-CONFIG USL Register 0x7E AUTO-CONFIG LSL Register 0x7F AUTO-CONFIG Target Level Register The following sections describe what each of the defaults do and recommendations for variations. Section A Register Address 0x2B MHD Rising 0x2C NHD Amount Rising ...
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Section C Register Address 0x41 ELE0 Touch Threshold 0x42 ELE0 Release Threshold 0x43 ELE1 Touch Threshold 0x44 ELE1 Release Threshold 0x45 ELE2 Touch Threshold 0x46 ELE2 Release Threshold 0x47 ELE3 Touch Threshold 0x48 ELE3 Release Threshold 0x49 ELE4 Touch Threshold ...
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Section E Register Address 0x5E Electrode Configuration Description: This register controls the number of electrodes being enabled and the mode the device is in. There are only two modes, Standby (when the value is 0x00) and Run (when the value ...
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MPR121 54 PACKAGE DIMENSIONS PAGE Sensors Freescale Semiconductor ...
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Sensors Freescale Semiconductor PAGE MPR121 55 ...
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MPR121 56 PACKAGE DIMENSIONS PAGE Sensors Freescale Semiconductor ...
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How to Reach Us: Home Page: www.freescale.com Web Support: http://www.freescale.com/support USA/Europe or Locations Not Listed: Freescale Semiconductor, Inc. Technical Information Center, EL516 2100 East Elliot Road Tempe, Arizona 85284 1-800-521-6274 or +1-480-768-2130 www.freescale.com/support Europe, Middle East, and Africa: Freescale Halbleiter ...