® PSoC Creator™ Component Datasheet Comparator (Comp) 1.80 Features Low input offset User-controlled offset calibration Multiple speed modes Low-power mode Output routable to digital logic blocks or pins Selectable output polarity Configurable operation mode during sleep General Description The Comparator (Comp) component provides a hardware solution to compare two analog input voltages. The output can be sampled in software or digitally routed to another component. Three speed levels are provided to allow you to optimize for speed or power consumption. A reference or external voltage can be connected to either input. You can also invert the output of the comparator using the Polarity parameter. When to Use a Comparator The Comparator can provide a faster comparison between two voltages than using an ADC. Although an ADC can be used with software to compare multiple voltage levels, applications requiring fast response or little software intervention are good candidates for this comparator. Some example applications include CapSense®, power supplies, or simple translation from an analog level to a digital signal. A common configuration is to create an adjustable comparator by connecting a voltage DAC to the negative input terminal. Cypress Semiconductor Corporation • 198 Champion Court • San Jose, CA 95134-1709 • 408-943-2600 Document Number: 001-73513 Rev. ** Revised October 14, 2011 ® Comparator (Comp) PSoC Creator™ Component Datasheet Input/Output Connections This section describes the input and output connections for the Comparator. An asterisk (*) in the list of I/Os states that the I/O may be hidden on the symbol under the conditions listed in the description of that I/O. Positive Input – Analog This input is usually connected to the voltage that is being compared. It can be routed to GPIOs and internal signals through analog globals, and to a selection of references. Negative Input – Analog This input is usually connected to the reference voltage. It can be routed to GPIOs and internal signals through the analog globals and to a selection of references. Comparator Out – Digital Output The output of the comparison. For noninverting configuration, this output goes high when the positive input voltage is greater than the negative input voltage. If the polarity is set to inverting, the output goes high when the negative input voltage is greater than the positive input voltage. The output can be routed to the digital interconnect and interrupt structures. clock – Digital Input * The clock input synchronizes the comparator output to the rising edge of the clock when the Sync parameter is set to Normal. This forces the comparator output to be sampled on the rising edge of the clock. When the Sync parameter is set to Bypass, the output is not synchronized and the clock input terminal is no longer displayed on the component symbol. Sync: Normal Page 2 of 14 Sync: Bypass Document Number: 001-73513 Rev. ** ® PSoC Creator™ Component Datasheet Comparator (Comp) Component Parameters Drag a Comparator onto your design and double-click it to open the Configure dialog. Document Number: 001-73513 Rev. ** Page 3 of 14 ® Comparator (Comp) PSoC Creator™ Component Datasheet The Comparator provides the following parameters. Hysteresis This parameter allows you to add approximately 10 mV of hysteresis to the comparator. This helps to ensure that slowly moving voltages or slightly noisy voltages will not cause the output of the comparator to oscillate when the two input voltages are near equal. Hysteresis Disabled Hysteresis Enabled Speed This parameter provides a way for you to optimize speed versus power consumption. Speed Options Description Ultra Low Power Use this setting for very low power applications. Slow (default) Use this setting for signals requiring response times slower than 80 ns. Fast Use this setting for signals requiring response times faster than 80 ns. PowerDownOverride Enabling the power down override parameter causes the comparator to stay active during Sleep mode. When the PowerDownOverride option is enabled, the customizer automatically sets the power mode to Ultra Low Power and remaining power options become unavailable. This is because Ultra Low Power is the only valid power mode for the comparator in Sleep mode. Note This parameter is only valid for PSoC 3 silicon. For PSoC 5 silicon, this feature is not supported and the GUI option is unavailable. Polarity This parameter allows you to invert the output of the comparator. This is useful for peripherals that require an inverted signal from the comparator. The sampled signal state returned by the software API and the comparator output seen by the power manager (see the System Reference Guide section on Alt Active and Sleep) is not affected by this parameter. Note Inversion logic for comparator is implemented using UDBs. Page 4 of 14 Document Number: 001-73513 Rev. ** ® PSoC Creator™ Component Datasheet Comparator (Comp) Polarity Options Description Inverting Output goes high when the positive input is less than the negative input Non-Inverting (default) Output goes high when the positive input is greater than the negative input Sync This parameter selects between synchronizing the output with a clock and connecting directly to the comparator output. When Norm is selected, the output changes on the rising edge of the clock input. Sync Options Description Norm (default) Sync the comparator output with the clock input. Bypass Connect the analog comparator directly to the output signal. Resources API Memory (Bytes) Digital Blocks Analog Block Datapaths Macro cells Status Registers Control Registers Counter7 Flash RAM Pins (per External I/O) Comparator fixed HW * N/A N/A N/A N/A N/A 597 2 3 *The Comparator component uses one analog comparator block. Application Programming Interface Application Programming Interface (API) routines allow you to configure the component using software. The following table lists the interface to each function. The subsequent sections cover each function in more detail. By default, PSoC Creator assigns the instance name “Comp_1” to the first instance of a component in a given design. You can rename the instance to any unique value that follows the syntactic rules for identifiers. The instance name becomes the prefix of every global function name, variable, and constant symbol. For readability, the instance name used in the following table is “Comp.” Function Description Comp_Start() Initializes the Comparator with default customizer values. Comp_Stop() Turns off the Comparator. Comp_SetSpeed() Sets speed of the Comparator. Document Number: 001-73513 Rev. ** Page 5 of 14 ® Comparator (Comp) PSoC Creator™ Component Datasheet Function Description Comp_ZeroCal() Zeros the input offset of the Comparator. Comp_GetCompare() Returns compare result. Comp_LoadTrim() Writes a value to the Comparator trim register. Comp_Sleep() Stops Comparator operation and saves the user configuration. Comp_Wakeup() Restores and enables the user configuration. Comp_Init() Initializes or restores default Comparator configuration. Comp_Enable() Enables the Comparator. Comp_SaveConfig() Empty function. Provided for future use. Comp_RestoreConfig() Empty function. Provided for future use. Comp_PwrDwnOverrideEnable() Enables Comparator operation in sleep mode. Only valid for PSoC 3 silicon. Comp_PwrDwnOverrideDisable() Disables Comparator operation in sleep mode. Only valid for PSoC 3 silicon. Global Variables Variable Comp_initVar Description Indicates whether the Comparator has been initialized. The variable is initialized to 0 and set to 1 the first time Comp_Start() is called. This allows the component to restart without reinitialization after the first call to the Comp_Start() routine. If reinitialization of the component is required, then the Comp_Init() function can be called before the Comp_Start() or Comp_Enable() function. void Comp_Start(void) Description: This is the preferred method to begin component operation. Comp_Start() sets the initVar variable, calls the Comp_Init() function, and then calls the Comp_Enable() function. Parameters: None Return Value: None Side Effects: If the initVar variable is already set, this function only calls the Comp_Enable() function. Page 6 of 14 Document Number: 001-73513 Rev. ** ® PSoC Creator™ Component Datasheet Comparator (Comp) void Comp_Stop(void) Description: Disables and powers down the comparator. Note This API is not recommended for use on PSoC 3 ES2 and PSoC 5 silicon. These devices have a defect that causes connections to several analog resources to be unreliable when not powered. The unreliability manifests itself in silent failures (for example, unpredictably bad results from analog components) when the component using that resource is stopped. When using this silicon, all analog components in a design should be powered up (by calling their respective _Start() APIs, for instance Comp_Start()) at all times. Do not call the Comp_Stop() APIs. Parameters: None Return Value: None Side Effects: None void Comp_SetSpeed(uint8 speed) Description: This function selects one of three speed modes for the comparator. The comparator power consumption increases for the faster speed modes. Parameters: uint8 speed: Speed parameter, see the following table for valid settings. Speed Options Description Comp_LOWPOWER Use this setting for very low power applications Comp_SLOWSPEED Use this setting for signals requiring response times slower than 80 ns Comp_HIGHSPEED Use this setting for signals requiring response times faster than 80 ns Return Value: None Side Effects: None Document Number: 001-73513 Rev. ** Page 7 of 14 ® Comparator (Comp) PSoC Creator™ Component Datasheet uint8 Comp_ZeroCal(void) Description: Performs custom calibration of the input offset to minimize error for a specific set of conditions: comparator reference voltage, supply voltage, and operating temperature. A reference voltage in the range at which the comparator will be used must be applied to the negative input of the comparator while the offset calibration is performed. The comparator component must be configured for Fast or Slow operation when calibration is performed. The calibration process will not work correctly if the comparator is configured in Low Power mode. Parameters: None Return Value: uint8: The value from the comparator trim register after the offset calibration is complete. This value has the same format as the input parameter for the Comp_LoadTrim() API ® ® routine. Refer to the PSoC 3, PSoC 5 Architecture TRM for a description of the comparator trim register. Side Effects: During the calibration procedure, the comparator output may behave erratically. During the calibration procedure, the analog routing switches for the comparator positive input are reconfigured. This reconfiguration may affect the analog signal routing for other components that are connected to the comparator positive input. When calibration is complete, all routing and comparator configuration registers are restored to the state they were in before calibration occurred. uint8 Comp_GetCompare(void) Description: This function returns a nonzero value when the voltage connected to the positive input is greater than the negative input voltage. This value is not affected by the Polarity parameter. This value always reflects a noninverted state. Parameters: None Return Value: uint8: Comparator output state. Nonzero value when the positive input voltage is greater than the negative input voltage; otherwise, the return value is zero. Side Effects: None void Comp_LoadTrim(uint8 trimVal) Description: This function writes a value into the comparator trim register. Parameters: uint8 trimVal: Value to be stored in the comparator trim register. This value has the same format as the parameter returned by the Comp_ZeroCal() API ® ® routine. Refer to the PSoC 3, PSoC 5 Architecture TRM for a description of the comparator trim register. Return Value: None Side Effects: None Page 8 of 14 Document Number: 001-73513 Rev. ** ® PSoC Creator™ Component Datasheet Comparator (Comp) void Comp_SaveConfig(void) Description: This function saves the component configuration and nonretention registers. It also saves the current component parameter values, as defined in the Configure dialog or as modified by appropriate APIs. This function is called by the Comp_Sleep() function. Parameters: None Return Value: None Side Effects: Empty function. Implemented for future usage. Calling this function has no effect. void Comp_RestoreConfig(void) Description: This function restores the component configuration and nonretention registers. It also restores the component parameter values to what they were prior to calling the Comp_Sleep() function. Parameters: None Return Value: None Side Effects: Empty function. Implemented for future use. Calling this function has no effect. void Comp_Sleep(void) Description: This is the preferred routine to prepare the component for sleep. The Comp_Sleep() routine saves the current component state. Then it calls the Comp_Stop() function and calls Comp_SaveConfig() to save the hardware configuration. Call the Comp_Sleep() function before calling the CyPmSleep() or the CyPmHibernate() function. Refer to the PSoC Creator System Reference Guide for more information about power management functions. Parameters: None Return Value: None Side Effects: None void Comp_Wakeup(void) Description: This is the preferred routine to restore the component to the state when Comp_Sleep() was called. The Comp_Wakeup() function calls the Comp_RestoreConfig() function to restore the configuration. If the component was enabled before the Comp_Sleep() function was called, the Comp_Wakeup() function will also re-enable the component. Parameters: None Return Value: None Side Effects: Calling the Comp_Wakeup() function without first calling the Comp_Sleep() or Comp_SaveConfig() function may produce unexpected behavior. Document Number: 001-73513 Rev. ** Page 9 of 14 ® Comparator (Comp) PSoC Creator™ Component Datasheet void Comp_PwrDwnOverrideEnable(void) Description: This is the power-down override feature. This function allows the component to stay active during sleep mode. Before calling this API, the Comp_SetPower() API should be called with the Comp_LOWPOWER parameter to set the comparator power mode to Ultra Low Power. This is because Ultra Low Power is the only valid power mode for the comparator in Sleep mode. The Comp_PwrDwnOverrideEnable() function is valid only for PSoC 3 silicon. It is not available for PSoC 5 silicon. Parameters: None Return Value: None Side Effects: None void Comp_PwrDwnOverrideDisable(void) Description: This is the power-down override feature. This function allows the comparator to stay inactive during Sleep mode. This API is valid only for PSoC 3 silicon and is not available for PSoC 5 silicon. Parameters: None Return Value: None Side Effects: None void Comp_Init(void) Description: Initializes or restores the component according to the customizer Configure dialog settings. It is not necessary to call Comp_Init() because the Comp_Start() routine calls this function and is the preferred method to begin component operation. Parameters: None Return Value: None Side Effects: All registers will be set to values according to the customizer Configure dialog. void Comp_Enable(void) Description: Activates the hardware and begins component operation. It is not necessary to call Comp_Enable() because the Comp_Start() routine calls this function, which is the preferred method to begin component operation. Parameters: None Return Value: None Side Effects: None Page 10 of 14 Document Number: 001-73513 Rev. ** ® PSoC Creator™ Component Datasheet Comparator (Comp) Sample Firmware Source Code PSoC Creator provides many example projects that include schematics and example code in the Find Example Project dialog. For component-specific examples, open the dialog from the Component Catalog or an instance of the component in a schematic. For general examples, open the dialog from the Start Page or File menu. As needed, use the Filter Options in the dialog to narrow the list of projects available to select. Refer to the “Find Example Project” topic in the PSoC Creator Help for more information. Functional Description The Comparator is functionally a high-gain high-bandwidth differential amplifier (an opamp with the compensation removed). The comparator is trimmed at the factory to achieve low input offset voltage. It can be trimmed at run time in the customer’s code to achieve improved input offset voltage precision at a specific point. Hysteresis is enabled by adding offsetting currents to the input stage. The nominal hysteresis is 10 mV (33 mV maximum), which is enough to be significantly larger than the sum of any input self noise of the comparator and internal routing interference. Input offset voltage is normally specified as the absolute value of the difference between the two inputs when the output of the Comparator switches state. DC and AC Electrical Characteristics for PSoC 3 The Comparator operates at all valid supply voltages. Comparator DC Specifications Parameter VIOFF VIOFF Description Conditions Typ Max Units Input offset voltage in fast mode Factory trim – 2.0 10 mV Input offset voltage in slow mode Factory trim – 2.0 10 mV 1 Custom trim – 1.0 4.0 mV Custom trim – 1.0 4.0 mV – 12 – mV – 10 33 mV Input offset voltage in fast mode Input offset voltage in slow mode 1 Min VIOFF Input offset voltage in ultra low power mode VHYST Hysteresis 1 Hysteresis enable mode The recommended procedure for using a custom trim value for the on-chip comparators can be found in the TRM. Document Number: 001-73513 Rev. ** Page 11 of 14 ® Comparator (Comp) Parameter VICM CMRR ICMP PSoC Creator™ Component Datasheet Description Conditions Input common-mode voltage Min Typ High current/fast mode 0 – Low current/slow mode 0 – VDDA V Ultra low power mode 0 – VDDA – 0.9 V Common-mode rejection ratio High current mode/fast mode Units VDDA – 0.1 V 30 60 – dB 2 – 250 400 µA 2 – 40 100 µA – 6.0 – µA Low current mode/slow mode Ultra low-power mode Max 2 Comparator AC Specifications Parameter TRESP Description Conditions Response time, high current 2 mode Response time, low current mode Response time, ultra low power 2 mode 2 Min Typ Max Units 50-mV overdrive, measured pin-to-pin – 80 110 ns 50-mV overdrive, measured pin-to-pin – 155 200 ns 50-mV overdrive, measured pin-to-pin – 55 – µs DC and AC Electrical Characteristics for PSoC 5 The Comparator operates at all valid supply voltages. Parameter VIOFF 2 Description Conditions Min Typ Max Units Input offset voltage in fast mode Factory trim, Vin ³ 0.5 V – – 15 mV Input offset voltage in slow mode Factory trim, Vin ³ 0.5 V – – 15 mV – ±12 – mV – 10 32 mV VIOFF Input offset voltage in ultra low power mode VHYST Hysteresis Hysteresis enable mode VICM Input common-mode voltage High current/fast mode VSSA – VDDA – 0.1 V Low current/slow mode VSSA – VDDA V Ultra low power mode VSSA – VDDA – 0.9 V CMRR Common-mode rejection ratio – 50 – dB ICMP High current mode/fast mode 2 – – 400 µA Based on device characterization (not production tested). Page 12 of 14 Document Number: 001-73513 Rev. ** ® PSoC Creator™ Component Datasheet Parameter Comparator (Comp) Description Low current mode/slow mode Ultra low-power mode Conditions 3 3 Min Typ Max Units – – 100 µA – 6 – µA Comparator AC Specifications Parameter TRESP Description Conditions Min Typ Max Units – 75 110 ns 50-mV overdrive, measured pin-to-pin – 155 200 ns 50-mV overdrive, measured pin-to-pin – 55 – µs Response time, high current mode 50-mV overdrive, measured pin-to-pin Response time, low current mode Response time, ultra low power 3 mode 3 Component Changes This section lists the major changes in the component from the previous version. Version 1.80 Description of Changes Updated configuration window with the accurate waveforms for Hysteresis enabled. Reason for Changes / Impact Previous waveforms for Hysteresis enabled did not provide enough information for ease of use. Added PSoC 5 DC and AC Electrical characteristics specifications to datasheet. 1.70 1.60 3 Comp_Stop() API changes for PSoC 5. Change required to prevent the component from impacting unrelated analog signals when stopped, when used with PSoC 5. Fixed an issue with using comparator as wakeup source for Sleep and Alt Active modes. Comparator was not configured correctly in previous version to use it as a wakeup source for Sleep and Alt Active modes. Changed Comp_SetSpeed() API to set the comparator trim values based on the speed settings. Comparator trim values were not properly set based on the speed settings in the previous version of the component. Comparator GUI updates To force the power mode to ultra low power when PowerDownOverride option is enabled. Updated configuration window with an accurate waveform including hysteresis. Previous configuration window did not provide enough information for ease of use. Based on device characterization (not production tested). Document Number: 001-73513 Rev. ** Page 13 of 14 ® Comparator (Comp) Version PSoC Creator™ Component Datasheet Description of Changes Corrected Hysteresis enable bit setting implementation Reason for Changes / Impact The meaning of the enable hysteresis bit was flipped. This has been corrected to correctly enable hysteresis on all versions of silicon Added characterization data to datasheet. Minor datasheet edits and updates. 1.50.a Added Known Problems and Solutions to datasheet To provide a workaround for hysteresis problem in PSoC 3 ES2 silicon. 1.50 Added Sleep/Wakeup and Init/Enable APIs. To support low power modes, as well as to provide common interfaces to separate control of initialization and enabling of most components. Updated Configure dialog with customized interface. The updated Configure dialog makes it easier to use. There is also a preview of how the component will change based on various selections. Added Power Down Override parameter to the Configure dialog. To allow configuration of Comparator to operate during sleep mode. Added Comp_PwrDwnOverrideEnable()/ Comp_PwrDwnOverrideDisable() APIs. To allow the component to stay active/inactive during sleep mode. © Cypress Semiconductor Corporation, 2011. The information contained herein is subject to change without notice. Cypress Semiconductor Corporation assumes no responsibility for the use of any circuitry other than circuitry embodied in a Cypress product. Nor does it convey or imply any license under patent or other rights. Cypress products are not warranted nor intended to be used for medical, life support, life saving, critical control or safety applications, unless pursuant to an express written agreement with Cypress. Furthermore, Cypress does not authorize its products for use as critical components in life-support systems where a malfunction or failure may reasonably be expected to result in significant injury to the user. The inclusion of Cypress products in lifesupport systems application implies that the manufacturer assumes all risk of such use and in doing so indemnifies Cypress against all charges. PSoC® and CapSense® are registered trademarks, and PSoC® Creator™ and Programmable System-on-Chip™ are trademarks of Cypress Semiconductor Corp. All other trademarks or registered trademarks referenced herein are property of the respective corporations. Any Source Code (software and/or firmware) is owned by Cypress Semiconductor Corporation (Cypress) and is protected by and subject to worldwide patent protection (United States and foreign), United States copyright laws and international treaty provisions. Cypress hereby grants to licensee a personal, non-exclusive, non-transferable license to copy, use, modify, create derivative works of, and compile the Cypress Source Code and derivative works for the sole purpose of creating custom software and or firmware in support of licensee product to be used only in conjunction with a Cypress integrated circuit as specified in the applicable agreement. Any reproduction, modification, translation, compilation, or representation of this Source Code except as specified above is prohibited without the express written permission of Cypress. Disclaimer: CYPRESS MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARD TO THIS MATERIAL, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A HALFICULAR PURPOSE. Cypress reserves the right to make changes without further notice to the materials described herein. Cypress does not assume any liability arising out of the application or use of any product or circuit described herein. Cypress does not authorize its products for use as critical components in lifesupport systems where a malfunction or failure may reasonably be expected to result in significant injury to the user. The inclusion of Cypress’ product in a life-support systems application implies that the manufacturer assumes all risk of such use and in doing so indemnifies Cypress against all charges. Use may be limited by and subject to the applicable Cypress software license agreement. Page 14 of 14 Document Number: 001-73513 Rev. **