Code Performance Analysis | Cypress CY4672 instruction

Keyboard

The interrupt latency includes two portions. The first portion is the time between the assertion of an enabled interrupt and the start of its ISR, which can be calculated using the following equation:

Latency1 = Time for current instruction to finish +

Time for M8C to change program counter to interrupt address + Time for LJMP instruction in interrupt table to execute.

For example, if the 5-cycle JMP instruction is executing when an interrupt becomes active, the total number of CPU clock cycles before the ISR begins are as follows:

(1 to 5 cycles for JMP to finish) + (13 cycles for interrupt routine) +

(7 cycles for LJMP) = 21 to 25 cycles.

In the example above, at 12 MHz, 25 clock cycles take 2.083 µs.

The second portion is the time between the start of the ISR and the set of the flag. For example, the row port interrupt (caused by pressing any key) takes 19 CPU clock cycles for this portion. There- fore, the Latency2 equals to 1.583 µs for the 12 MHz CPU.

Consequently, the total latency for a button interrupt is Latency1 + Latency2 = 3.667 µs

4.3.12Code Performance Analysis

A key press report is used to analyze the code performance. A typical key press report contains the following steps:

■A key press interrupts the MCU. The prior section has calculated that it takes 3.667 µs for MCU to responds to this Interrupt.

■MCU exits the sleep state, scans the Bind button and turns on the timer. It takes 40.8 µs.

■MCU calls function scan_keyboard() to detect which key is pressed. This function consumes 1.15 ms.

■MCU calls function generate_standard_report() to format the report and send the report to the bridge. This step takes 2.01 ms, which includes 1.66 ms radio transmission time.

As a result, it takes 3.20 ms for the keyboard to report a key press to the bridge.

CY4672 Reference Design Guide, Document # 001-16968 Revision **

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Cypress CY4672 manual Code Performance Analysis

Contents

CY4672 Reference Design Guide Disclaimer Copyrights Contents 4.1 2.3 Programmable Interval Timer User Module 2.42.1 2.2 9.3 9.19.2 6.18 2.4 1 Millisecond Interval Timer User Module 2.56.16 6.17 100 1.11.2 1.3 109 105107 108 Support IntroductionScope Chapter Overviews Acronyms ConventionsDefinitions Rssi Introduction Pseudo Noise Codes WirelessUSB ProtocolGeneral Overview Radio Channel Management Manufacturing ID Chip Error CorrectionAutomatic Acknowledgment AutoACK Network ID Channel Selection Algorithm Protocol Modes KISSBind Mode Ping Mode Bridge OnlyIdle Mode Bind Mode Reconnect Button Bind Mode Idle Mode HID onlyReconnect Mode HID only Enhanced KISSBind Slave Back Channel Data Support Data ModeUnbind Back Channel Transaction Sequence Dynamic Data Rate Dynamic Data Rate and Dynamic PA Bind/KISSBind Request Packet HID Packet Structures Device Type Bind Response Packet BridgeConnect Request HID Connect Response Packet Bridge Data Byte 0-N This is byte-aligned application data Ping Packet BridgeData Packet/Back Channel Data Packet Bridge and HID Bind and Reconnect Timing Bind Timing Diagram Device Signature Byte TEA Encryption TEA Key Management over WirelessUSBEncryption TEA Encryption Key Management AES Encryption AES Key Management Encryption and Power Consumption Trade Off WirelessUSB Protocol Introduction Design FeaturesRDK Mouse Assembly Mouse Bottom View Bind Button and On-Off Switch Schematics Hardware Block Diagram 1 ROM/RAM Usage PRoC LP Device ConfigurationFirmware Architecture Hardware Considerations CYRF69103 Device Architecture SPI Master User Module Global Configuration Flash Security Programmable Interval Timer User ModuleModel SPI Module Common CodeGenerated Library Code Debounce Module Flash Module Timer ModuleRadio Driver Protocol Module Mouse Module Application CodeISR Module Testmode Module Optical Module Wheel Module Buttons ModuleMfgtest Module Battery Module Configuration Options Mfgtxmodes PlatformhMOUSE800NOT400CPI Mfgtestcode Kissbind Wireless Protocol Data PayloadPlatform and Architecture Portability Initialization Byte Interrupt usage and timingPacket Format 9.2 Packet Format Tools Development EnvironmentCode Performance Analysis 2.1 M8C Sleep Watchdog TimerTips and Tricks Critical Test Points Keyboard Keyboard Plastic RDK Keyboard Assembly Radio and PSoC Board PDC-9265 Bind Button Schematic Row Keyboard Matrix Build Option ROM Usage RAM Usage Bytes EnCoRe II Device ConfigurationTotal ROM Total RAM Bytes Microcontroller Device Architecture This parameter is set to ‘1’ This parameter is set to EnableThis parameter is set to Disable This parameter is set to Tcap Reset Application TimerIsr Keyboard Module Test Module Encrypt Module Keyboardkeepalivetimeout Encryptaes TimercalEncrypttea Mouseemulationmode Keyboard Application Report Formats Modifier Reserved Scan Code Keys 0x00 Byte Name0xFC Modifier Reserved Scan Code Keys 0x00 0x04 Application Report Power Key Scan Interrupt Usage / Timing Ghost Key Detection Code Performance Analysis Build the firmware, the new key ‘My Computer’ will work Modifying the Keyboard Matrix or Adding New KeysModifying the Keyboard Matrix Adding New Keys RDK Keyboard with POD Installed 10. RDK Keyboard Test Points Bridge In-System Programming Bridge Photographs RDK Bridge with USB Adapter and PSoC MiniProg Schematics LED Usage Build Option ROM Usage Bytes RAM Usage Bytes Total ROM Bytes Total RAM Bytes CYRF69213 Device Architecture This parameter is set to 4.44 4.53 This parameter is set to 1Hz USB Device User Module 2.4 1 Millisecond Interval Timer User Module Modules consist of the common code logical grouping PSoC Generated Library Code Bridge Module TimerFlash Master Protocol USB Module Mfgtestcode Dalenable Powerbind Parameter Icc Units Suspend and Remote WakeupInterrupt Usage/Timing Polling method is used for the Bind button USB Descriptors USB Interface Keyboard HID Report Descriptor Device/Config Descriptors Keyboard HID Report Descriptor Endpoint Mouse/Keyboard HID Report Descriptor Bridge Keyboard power keys use Report ID Keyboard Report Format Reserved Standard Key Keyboard Endpoint EP1 Usage ID Usage Name Wheel Battery Level and Link Quality ReportsMouse Report Format Mouse Endpoint EP2 Report ID Unused Obtaining the RadioParams Report Requesting a New Battery Reading 17. Example keyboard Catc Trace Standard and MM Keys Example USB Bus Analyzer Catc Traces 18. Example Mouse Catc Trace Key Up 19. Example Keyboard Catc Trace Power Key Few of ways for working with the kit are the following Development and Debug Environment MTK Serial Protocol MTK Block DiagramManufacturing Test Support, MTK Serial Response Protocol Serial Command ProtocolCommand Command Description MTK DUT Source Code Porting Accessing MTK in the DUTSerial Port Parameter Settings MTK RF Protocol Manufacturing Test Support, MTK Test Parameter FCC Limit Measured Value Margin Regulatory Testing Results Regulatory Testing Results Usage Model Power ConsiderationsOperation Mode Icc mA with Average Icc Supply Voltage = RDK Keyboard RDK Mouse Battery Life CalculationsMode Hrs/day Days Average Icc mA Charge mAh Active mode-Move the mouse in a circle on white Paper Power Considerations USB HID API module Software GuideSoftware Code Modules Method Type Description CHidDevice Class MethodsCHidDeviceClass Methods CHidManagerClass Methods CHidManager Class Methods CCySysTray Methods System Tray ModuleCCySysTray Class Methods CWirelessUSBTrayApp Class Methods WirelessUSB System Tray Application Module CMainFrame Class Methods OnStopTimer Public This method stops the timer OnTimer CWirelessUSBStatusPropertySheet Class Methods CWirelessUSBStatusPropertyPage Class Methods CHidTrayManager Class Methods CHidTrayDevice Class Methods Appendix A. References + Feedback Numerics Index LED Pseudo noise codes 13, 14 PSoC Designer generated files Index Revision History + Feedback