DRM050, 2.4-GHz Wireless Optical Mouse And Multimedia

Freescale Semiconductor, Inc.RF Front EndThe received serial data will pass into the interface IC RFW-D100, inwhich it will be converted to parallel data for the MCU.Mouse & KeyboardAntenna6-24MHzFreescale Semiconductor, Inc.XtalMCU GPIOs(JB8/LJ24)RFW-D100Serial to parallel interfaceKeyboard/MouseRFW-102ModuleParallel Add/Data bus3.3VDC-DCBatteryUSB DongleAntenna6-24MHzRFW-102ModuleParallel Add/Data busRFW-D100Serial to parallel interfaceXtalMCU USB–I/F(JB16)Power CircuitDC-DC3.3VUSB 5V2.3 RF Transceiver Module RFW102The RFW102 transceiver module is a short-range, half-duplex wirelessradio transceiver. The transceiver is intended for use in the unlicensedISM band of 2400–2483.5 MHz.The transceiver module provides a peak output power of 2 dBm and datarate up to 1Mbps. Power consumption during transmit is extremely low,(21 mA in 1Mbps, 28 mA in 1 kbps), which is directly dependent on thebit transfer rate. During standby mode, the transceiver consumes almostno power and features an extremely short wake up time of 20 ms.The communication link between the transceivers is a Direct SequenceSpread Spectrum (DSSS) pulse pipe. The modulation scheme is 100%Designer Reference Manual12DRM050 — Rev 0RF Front EndFor More Information On This Product,Go to: www.freescale.comMOTOROLA

Freescale Semiconductor, Inc.RF Front EndRF Transceiver Module RFW102Amplitude Shift Keying (ASK). The spreading modulation scheme is aBi-Phase modulation where each bit has a 13-bit Barker series.Freescale Semiconductor, Inc.Below are the key features of the transceiver module: 2.4-GHz unlicensed ISM band operation 1 Mbps data rate Sample 3 line digital interface Low power consumption 2 dBm typical peak output transmission power –80 dBm typical sensitivity Typical standby current of 2.6 mA Compiles with FCC regulation Wide range operating voltage (2.7 V–3.6 V) Direct Sequence Spread Spectrum (DSSS) 11 dB processing gain Short signal acquisition time (1.2 ms)The transceiver has a fully digital serial I/O interface providing a simple3-line interface. Tx/Rx is for controlling of the transceiver work in transmitor receive mode. Act is used for switching the transceiver betweenworking mode and sleep mode. Data IO is the data transfer channel.The transceiver chipset includes three chips. RFW24 — An RFIC performs all of the timing, amplifying,switching, transmitting, and receiving functions. RFW488C — A 4-pin SAW correlator, which is used as a directsequence spread spectrum spreading and de-spreading element. RFW488R — A 1-port SAW resonator, which serves as thesystem oscillation source.For detailed information on the internal implementation of the transceivermodule, please refer to the data sheet about the RFW102 fromRFWaves website:http://www.rfwaves.comDRM050 — Rev 0MOTOROLADesigner Reference ManualRF Front EndFor More Information On This Product,Go to: www.freescale.com13

Freescale Semiconductor, Inc.RF Front End2.4 Interface IC RFW-D100The RFW-D100 is a complimentary IC to the RFW-102 module. Itprovides an MCU with a parallel interface to the RFW-102 transceivermodule and other features that enable implementing a protocol suitablefor wireless communication with a small burden on the MCU.Freescale Semiconductor, Inc.In HID application, the MCU is in charge of the MAC layer protocol. TheRFW-D100 is used to reduce the real-time demands of the MCUhandling the MAC protocol. It converts the fast serial input to 8-bit words,which are much easier for 8-bit MCUs to work with. Also, it buffers theinput through a 16-byte FIFO, giving the MCU access the RFW-D100efficiently. Instead of reading one byte per interrupt, the MCU can readup to 16 bytes in each interrupt.Below are the features of the RFW-D100 interface IC: Provides parallel interface with the RFW102 modem Serial to parallel conversion of the RFW102 interface Input FIFO (RX FIFO) Output FIFO (TX FIFO) Preamble Correlation Packet Address Filter CRC calculation Watchdog Timer driven by internal RC oscillator Power saving mode: Idle, Power-down. Receiver signal strength indication (RSSI)For detailed information on the RFW-D100, please refer to the datasheet about the RFW-D100 from the RFWaves website:http://www.rfwaves.comDesigner Reference Manual14DRM050 — Rev 0RF Front EndFor More Information On This Product,Go to: www.freescale.comMOTOROLA

Freescale Semiconductor, Inc.RF Front EndAntenna and PCB Specification2.5 Antenna and PCB SpecificationThe antenna interface of the RFWaves module RFW102 is 200 Ωdifferential. For matching and placement of different antenna, refer to thedata sheet of the specific antenna you are using.Freescale Semiconductor, Inc.The reference antenna of the RFWaves transceiver module RFW102-Mused here is a special design printed circuit board differential loopantenna. The purpose of this design is aimed at low cost, small formfactor, and high directivity design.For the dimension and PCB specification of the antenna board, pleaserefer to documents which can be download from RFWaves website:http://www.rfwaves.comDRM050 — Rev 0MOTOROLADesigner Reference ManualRF Front EndFor More Information On This Product,Go to: www.freescale.com15

Freescale Semiconductor, Inc.Freescale Semiconductor, Inc.RF Front EndDesigner Reference Manual16DRM050 — Rev 0RF Front EndFor More Information On This Product,Go to: www.freescale.comMOTOROLA

Freescale Semiconductor, Inc.Designer Reference Manual — DRM050Section 3. Optical Mouse TransmitterFreescale Semiconductor, Inc.3.1 IntroductionThe JB8 has 8K Flash memory, 3-MHz bus processing power, 16-bit2-channel timer module, and appropriate number of I/O pins makes thisMCU suited for this 2.4-GHz Wireless Optical Mouse application. Themain features of the reference design include: 2.4-GHz RF Link 1 Mbps data rate 800 DPI Resolution Smart Power Management3.2 System OverviewThe optical mouse consists of the JB8, the Agilent optical mouse sensorADNS-2030, the baseband IC and RF Module from RFWaves, andDC/DC converter. Figure 3-1 shows the block diagram of the system.DRM050 — Rev 0MOTOROLADesigner Reference ManualOptical Mouse TransmitterFor More Information On This Product,Go to: www.freescale.com17

Freescale Semiconductor, Inc.Optical Mouse TransmitterLOOPANTENNAL2.4 GHz RFTransceiverModuleMRL2R2Freescale Semiconductor, E0SCLKPTE1SDIOPTE2PDIMAGESENSORXY LEDPTA4(16-pin PDIP)BasebandMAC ICD100DGNDPTA5PTA6RFD INTIRQDATA BUSADDRESS / CTL BUSPTB7-PTB0Z2RSTOSC210MPTC7-PTC0OSC1DC/DC Converters3.3V and 5VZ-axisEncoderZ1X1100nF30pF6MHz30pF(44-pin QFP)Figure 3-1. Mouse Block Diagram3.2.1 Microcontroller JB8The functions of the JB8 are to get the XY displacement from the sensor,detect the Z displacement, check button status, control the baseband ICto sending out data, and perform the overall power management.Three standard left, middle, and right buttons (and two additional buttonsreserved for future development) are implemented.3.2.2 Optical Mouse SensorThe AN2030 is a 3-V supply sensor specially design for wireless opticalmouse. The communication between the sensor and the JB8 is throughSerial Peripheral Interface with clock input at the SCLK pin andbidirection data interface at SDIO pin. The Power Down (PD) pin is usedto power down the sensor when it’s not in use.Designer Reference Manual18DRM050 — Rev 0Optical Mouse TransmitterFor More Information On This Product,Go to: www.freescale.comMOTOROLA

Freescale Semiconductor, Inc.Optical Mouse TransmitterSystem Overview3.2.3 RF TransmissionThe data from the MCU will be transferred to the baseband IC for parallelto serial packet conversion as well as error checking. The encoded datawill be passed to the RF module for ASK modulation in IF band andfrequency spreading with DSSS scheme. The modulated signal will befurther up-converted into 2.4-GHz ISM band for final transmission.Freescale Semiconductor, Inc.3.2.4 DC/DC ConverterThe power supply for a handheld device should be able to keep the DCvoltage output at a constant level even though the input battery voltageis continuously dropping down. There are two DC/DC converters; the3.3-V supply is used for the baseband IC and RF module. The 5-Vsupply is only used for the JB8, but it would be eliminated in the finalproduct when the low-voltage version JT8 is used.DRM050 — Rev 0MOTOROLADesigner Reference ManualOptical Mouse TransmitterFor More Information On This Product,Go to: www.freescale.com19

Freescale Semiconductor, Inc.Freescale Semiconductor, Inc.Optical Mouse TransmitterDesigner Reference Manual20DRM050 — Rev 0Optical Mouse TransmitterFor More Information On This Product,Go to: www.freescale.comMOTOROLA

Freescale Semiconductor, Inc.Designer Reference Manual — DRM050Section 4. Mouse Transmitter Firmware4.1 MAC Layer ProtocolFreescale Semiconductor, Inc.Each piece of firmware on the mouse, keyboard, or dongle consists of aMAC layer implementing the RFWaves Carrier Sense Multiple Access(CSMA) protocol. In CSMA protocol, every device in the network usesthe same physical channel for communication. Each device will firstdetect whether the channel is being used by others before it initiates itsown transmission.The MAC layer manages the wireless communication between themouse/keyboard and the dongle through the baseband RFW-D100 IC.The MAC layer implements two interrupt functions from each of theMCUs. The IRQ and one Timer Channel are used by the MAC.Interface functions have been built for the application to access theMAC. For example, the application layer can invoke these functions: Initiate the MAC layer and the RF hardware Initiate transmission of a new packet Initiates a packet receiving by the MAC layer Check and locate any newly received packet in the MAC buffer Sets the MAC and RF hardware to low power mode, or resumefrom itThe “MACAPI.H” header file in each of the firmware contains moredetails about these functions and their uses.DRM050 — Rev 0MOTOROLADesigner Reference ManualMouse Transmitter FirmwareFor More Information On This Product,Go to: www.freescale.com21

Freescale Semiconductor, Inc.Mouse Transmitter Firmware4.2 Application Firmware FlowFigure 4-1 shows the main application firmware flow of the wirelessoptical mouse. One of the main challenges in wireless optical mousedesign is the power management to minimize the power consumptionand maximize the performance.Freescale Semiconductor, Inc.MAIN PROGRAMINITIATE SENSOR,AND RF HARDWAREGET XY DISPLACEMENTFROM SENSORGET Z DISPLACEMENTFOR EVERY MSIRQ ISRIRQ DRIVEN BYYESPERIODICALWAKEUP SIGNAL?NOSERVE THE INTERRUPTEVENT FROMRFW-D100 BASEBAND CHIPDISABLE THE PERIODICALWAKEUP FOR MCU TO CHECKMOVEMENT AND BUTTONSCHECK BUTTONFOR EVERY MSNNEWMOUSE DATA?YINIT MAC TOTRANSMIT DATAPOWER MANAGEMENTFigure 4-1. Firmware StructureDesigner Reference Manual22DRM050 — Rev 0Mouse Transmitter FirmwareFor More Information On This Product,Go to: www.freescale.comMOTOROLA

Freescale Semiconductor, Inc.Mouse Transmitter FirmwarePower Management for the MouseFreescale Semiconductor, Inc.The main program continually checks the registers of the sensor to seeif any XY movement happened. If any XY movement is detected, it getsthe X and Y displacements from the sensor registers, puts them in theFIFO buffer and sets the corresponding flags. For every ms timer tick, itchecks the Z movement and the buttons’ status. If new mouse data hasbeen detected, JB8 will initiate the RF data transmission through thebaseband RFW-D100 IC.Apart from serving the interrupt events from the baseband D100 ICduring normal operation, IRQ serves as the periodical wakeup signalwhen JB8 is in sleep mode. The JB8 must check whether there is anynew movement or if the buttons’ status changed. IRQ ISR firmware willdetermine what appropriate actions must be taken.4.3 Power Management for the MouseSensor fully turned onZLED turned onfor every 700usxy no movementfor 5sHIGH CURRENTxy movementxy movementSensor and ZLED turnedon for every 250msSLEEPz movementor buttonSensor turned on every25ms, ZLED turned onfor every 700usPOWER SAVING(STARTUP)xyz no movementandno button for 50sFigure 4-2. Power ManagementDRM050 — Rev 0MOTOROLADesigner Reference ManualMouse Transmitter FirmwareFor More Information On This Product,Go to: www.freescale.com23

Freescale Semiconductor, Inc.Mouse Transmitter FirmwareFigure 4-2 shows the flow of the power management. There are threedefined stages — Power Saving, High Current, and Sleep stage.Freescale Semiconductor, Inc.After power up, the mouse is put in Power Saving stage. In this stage,the sensor is only turned on for every 25 ms to see if any XY movementoccurred. The Z movement and buttons are sensed for every ms.If no activity happens in 50 seconds, it enters the Sleep stage. In thisstage, the JB8 is put in stop mode and will be woken up every 250 ms tomonitor any activity. The RFW-D100 and RFW-D102 IC are in idle mode(not in power down mode). Their power consumption will be reducedbecause the system CLK to RFW-D100 has been stopped (JB8 andRFW-D100 share the same crystal CLK source).Any XY movement will cause the mouse to enter the High Current stage.At this stage, the sensor is powered on and XY movement is continuallymonitored. The Z movement and buttons’ activities are still monitored forevery ms. If no XY movement happens in 5 seconds, it then entersPower Saving Stage.Except for the 1 ms timer tick, all the above mentioned timings canconfigured by changing their constant values.4.4 Output Buffer Format for the RF PacketUsers may refer to the RFWaves RFW-D100 IC data sheet for moredetail about the RFWaves Packet Structure (Rev 1.3, Appendix B).Figure 4-3 shows the output buffer format for the mouse RF packet. Thecontents of this will be transmitted when invoking the transmissionfunction. Users can refer to the “TransmitData” function in “main.c” of thereference firmware as an example.The first byte is the total size of the buffer data (equal to 11 here). Bytes2 through 5 are the Network ID which is used to distinguish differentRFWaves Networks. Byte 6 is the node ID which is used for identificationof different device within the network. The last four bytes are the mousedata.Designer Reference Manual24DRM050 — Rev 0Mouse Transmitter FirmwareFor More Information On This Product,Go to: www.freescale.comMOTOROLA

Freescale Semiconductor, Inc.Mouse Transmitter FirmwareOutput Buffer Format for the RF PacketThe contents of the output buffer will be received by the JB16 dongle anddongle can extract the mouse data and send to the host through USB.Output Buffer StructureFor for Mouse RF PacketFreescale Semiconductor, Inc.Packet SizeNetwork ID byte1Network ID byte2Network ID byte3Network ID byte4Node IDReserved for SequencePacket SizeButton gure 4-3. Output Buffer Format for the Mouse PacketDRM050 — Rev 0MOTOROLADesigner Reference ManualMouse Transmitter FirmwareFor More Information On This Product,Go to: www.freescale.com25

Freescale Semiconductor, Inc.Freescale Semiconductor, Inc.Mouse Transmitter FirmwareDesigner Reference Manual26DRM050 — Rev 0Mouse Transmitter FirmwareFor More Information On This Product,Go to: www.freescale.comMOTOROLA

Freescale Semiconductor, Inc.Designer Reference Manual — DRM050Section 5. Multimedia Keyboard TransmitterFreescale Semiconductor, Inc.5.1 IntroductionThe LK24 has a built-in PLL with a low frequency crystal (32.768 kHz)and is able to operate as fast as 4 MHz bus speed at 3.3 V. It containsenough I/O pins for key matrix scanning. The main features of thekeyboard include: 2.4-GHz RF Link 1 Mbps data rate Power management keys (power, wake and sleep) supportMultimedia keys support5.2 System OverviewThe keyboard transmitter consists of the LK24, the baseband IC and RFModule from RFWaves, and DC/DC converter. Figure 5-1 shows theblock diagram of the system.DRM050 — Rev 0MOTOROLADesigner Reference ManualMultimedia Keyboard TransmitterFor More Information On This Product,Go to: www.freescale.com27

Freescale Semiconductor, Inc.Multimedia Keyboard TransmitterLOOPANTENNAMC68HC908LK24[Externalpullup R]2.4 GHz RFTransceiverModulePTF0-7PTC0-7PTB6-7COL[0:17]Key MatrixFreescale Semiconductor, Inc.(8 rows x 18 columns)PTA0-3PTD4-7BasebandMAC ICD100ROW[0:7][Externalpullup R]RFD INTDATA BUSADDRESS / CTL C/DC Converter3.3VX1OSC132.768kHz10pF(80-pin LQFP)Figure 5-1. Keyboard Block Diagram5.2.1 Microcontroller LK24The functions of the LK24 are to scan the key matrix and determine whatkeys are pressed and released, control the baseband IC to sending outdata, and perform the overall system control.5.2.2 RF TransmissionThe data from MCU will be transferred to the baseband IC for parallel toserial packet conversion as well as error checking. The encoded datawill be passed to the RF module for ASK modulation in IF band andfrequency spreading with DSSS scheme. The modulated signal will befurther up-converted into the 2.4-GHz ISM band for final transmission.Designer Reference Manual28DRM050 — Rev 0Multimedia Keyboard TransmitterFor More Information On This Product,Go to: www.freescale.comMOTOROLA

Freescale Semiconductor, Inc.Multimedia Keyboard TransmitterSystem Overview5.2.3 DC/DC ConverterFreescale Semiconductor, Inc.The power supply for a handheld device should be able to keep the DCvoltage output at a constant level even though the input battery voltageis continuously dropping down, so a 3.3 V DC/DC converter is designedfor the whole system, including the MCU and the baseband IC and RFmodule.DRM050 — Rev 0MOTOROLADesigner Reference ManualMultimedia Keyboard TransmitterFor More Information On This Product,Go to: www.freescale.com29

Freescale Semiconductor, Inc.Freescale Semiconductor, Inc.Multimedia Keyboard TransmitterDesigner Reference Manual30DRM050 — Rev 0Multimedia Keyboard TransmitterFor More Information On This Product,Go

8 System Overview MOTOROLA 1.3 System Overview Figure 1-1. System Overview The system consists of three functional devices, a wireless optical mouse using the MC68HC908JB8 (hereafter referred as JB8, production version uses the low voltage MC68HC08JT8), a wireless multimedia keyboard using the MC68HC908LK24 (hereafter referred as LK24), and