User Guide - CompuPhase
Contents
1. also called phono connectors or CINCH connectors For good sound quality the input impedance of the equipment e g an amplifier that is attached to the audio outputs should be at least 2 7 kQ When connecting the audio outputs to equipment with low impedance low frequencies are cut off Button inputs Connector block J5 allows up to 16 switches to be attached to the controller A switch is down when the sense pin is shorted to the respective ground pin see the table below Each sense pin has a weak pull up a bounce filter and a Schmitt trigger hysteresis circuit The maximum switch frequency that can be detected is 50 Hz The switch inputs may also be used to detect logic levels from other digital equipment such as TTL levels Because of the internal pull up resistors open drain outputs can be connected to the sense pins as well J5 is a 2 54 mm pitch IDC header The triangle on the connector indicates pin 1 1 Switch 0 sense pin 2 Ground ie eg 3 Switch 1 sense pin 4 Ground OO 5 Switch 2 sense pin 6 Ground OO 7 Switch 3 sense pin 8 Ground OO 9 Switch 4 sense pin 10 Ground OO 11 Switch 5 sense pin 12 Ground aes 13 Switch 6 sense pin 14 Ground E A 15 Switch 7 sense pin 16 Ground 00 17 Switch 8 sense pin 18 Ground OO 19 Switch 9 sense pin 20 Ground OO 21 Switch 10 sense pin 22 Ground OO 23 Switch 11 sense pin 24 Ground aes 25 Switch 12 sense pin 26 Ground s A 27 Switch 12. back the encrypted tracks When ordering a series of MP3 players a customer may request a unique device key for that series In addition to the key the customer also receives a programs for encrypting MP3 tracks D3 tag information version 2 is preserved and non encrypted However the ID3 tag should not be modified after encrypting the file 13 Troubleshooting If you have a multimeter verify the voltage and the polarity of the power supply Refer to page 15 for the power requirements and to page 4 for the polarity A tension that is too high or an inverted polarity may damage the device To verify the basic operation of the device reformat the CompactFlash card with FAT or FAT32 and put a single MP3 file on the CompactFlash card The card should not contain any script AUTORUN AMX The name of the MP3 track is not important but the file extension must be mp3 Connect power to the H0420 and then insert the CompactFlash card After a short delay 1 or 2 seconds the LED behind the RS232 connector should light up and stay on for the duration of the MP3 track If you connect the audio outputs of the MP3 controller to an amplifier or to amplified speakers you will be able to hear the track playing For MP3 tracks that contain large D3 tags see page 12 it may take several seconds before audio output starts If the above test fails remove power and the CompactFlash card Then connect a serial cable between the H0420 MP
3. sampling RCS codes x res init 11 set up a display for visual feedback console 16 4 settimer 500 rcShandler code repeat switch code case RCS_Channelup nexttrack repeat case RCS_ChannelDown prevtrack repeat case RCS_Stop stop case RCS Play playtrack case RCS _VolumeUp volumeup Fra lies a an ACE lm 1 1 rac ia Ika I wa l I irom om lt Press F1 for help E E m Ln z1 col 1 The Quincy IDE A minimal script that plays one file on power on and then stops is reset Oley Moiese Olell ames The H0420 controller does not interpret the source code of the script directly but it executes a compiled form of the script You can compile directly from the Quincy IDE or use the separate PAWN compiler in a console window or DOS box The PAWN compiler generates the file AUTORUN AMX from the input file which is the name that the H0420 requires The next steps are to copy the AUTORUN AMX file to the CompactFlash card in the root directory insert that card in the H0420 controller and restart the controller In the Quincy IDE you can also adjust the output path so that the source file gets compiled directly onto the CompactFlash card Typically a script must do a lot more than play just a single file At the very least it should allow to re start playing one or more audio files without needing to power cycle the device More commonly the script must react on user inp
4. voltage to be within the range that the device supports and that the polarity is correct See page 15 for the specifications and page 4 for the power connector Voltages outside the appropriate range may cause malfunction Voltages above the high limit or with inverted polarity may damage the device Legal disclaimer ITB CompuPhase shall not be liable for the incidental or consequential losses or damage to tangible property injury or death of a person in connection with the use of this device Although the examples in this guide have been tested with care they may contain errors and they are not guaranteed for any particular purpose Overview of the H0420 The H0420 is a compact and solid state general purpose controller with an embedded MP3 audio decoder that runs under the control of a scripting language The audio fragments and the script that controls the operation and behaviour of the MP3 player are stored on a CompactFlash card Auxiliary devices such as an LCD electronic switches or data terminals may be attached through a 16 bit general purpose I O bus a standard header connector supporting 16 switches and an RS232 connector respectively This booklet introduces the scripting capabilities of the H0420 MP3 controller For technical details and a programming reference please see the documentation that is provided in Adobe Acrobat format on the CD ROM that comes with the product The script controls the operation of the H0420
5. with schmitt trigger and bounce filter Digital Osaera 16 pins TTL level at max 10 mA source 0 9 mA sink filtered to max 50 kHz max switching rate 4 kHz configurable per pin Analogue Output cccccccccecceeeeeeeeees 1 pin 0 to 5 V software controlled Real Time cloCk ssssesisiriesssisssnesssss accurate to 2 5 seconds per 24 hours Mechanical DIMENSIONS cceeeeeccceesecceeeeesceeeee sees 70 x 100 x 18 mm length x width x height the CompactFlash card exceeds the edge with max 3 mm W C10 IG 2 iasestsivscatvoscceccendeteimecedasedpoiaansaceat 0 065 kg INV OAR 1 Osco areectarierteenacenmanicteplantcoecteaneiecees 4 holes 3 1 mm spaced centre to centre at 90 mm horizontally and 60 mm vertically mounting holes are electrically connected to digital analogue ground 3 mm of clearance is needed below the PCB Operating conditions Tempera tne esseni a designed for 40 C to 85 C Firmware Operating System cccessscceeeeeeees FreeRTOS version 3 2 4 see http www freertos org Virtual Machine eee eeecceeceeeceee PAWN AMX see http Awww compuphase com pawn 13016 014 015 0 0 ee Block TEA amended version 128 bit key see Fast Software Encryption 2 ISBN 3540605908 15
6. 0 mm vertically Ensure at least 3 mm of clearance below the PCB See the datasheet for details and drawings The mounting holes are electrically connected to the digital and analogue ground of the device When the H0420 ground must be isolated from a grounded metal enclosure use nylon washers and nylon machine screws for fastening Contents of the CD ROM The product comes with a CD ROM containing Several ready to run and fully documented scripts that can be configured through an INP file and a playlist file No programming is required to run these scripts The PAWN development tools the compiler the debugger and configuration files Auxiliary utilities such as a file transfer utility and a serial monitor program An assortment of example scripts in source code form to get you starting with programming the H0420 MP3 controller Extensive documentation in Adobe Acrobat format the PAWN language manual the H0420 programming reference and the H0420 datasheet with detailed electrical and mechanical information Example MP3 tracks for testing purposes Installing the development tools On Microsoft Windows run the application called Setup on the CD ROM Then follow the directions of the installation utility The installer allows you to choose various optional components for installation The CD ROM also contains all files and tools in uncompressed form This may be convenient if you do not wish to install the entir
7. 3 controller and a PC this must be a straight cable do not use a null modem cable If your PC lacks a serial RS232 port you can alternatively use a converter from USB to RS232 On the PC launch The Termite utility that comes with the H0420 other serial terminal programs work too Please verify that the COM port is correct and that the serial settings are Baud rate 57600 Data bits 8 Parity none Stop bits l Hardware handshake none With the serial cable connected but without CompactFlash card inserted plug the power cable into the H0420 MP3 controller If the device was already powered disconnect the power plug and reconnect it after a two second delay this is called a power cycle After connecting the power the terminal program should display a message similar to H0420 C 1 7 4036 The letter C may also be a CE depending on the options 1 7 is the version number of the firmware and 4036 is an internal revision number If the above line of text does not appear check the serial cable and the settings of the terminal program Make sure that you use the correct COM port If the H0420 persists in remaining silent please verify the power supply After passing the above test insert the CompactFlash card in the H0420 MP3 controller without removing the power connector The terminal window should display Start up and start playing the MP3 track on the card after a short delay If the terminal window shows a
8. 3 sense pin 28 Ground Raoul 29 Switch 14 sense pin 30 Ground 31 Switch 15 sense pin 32 Ground 33 Not connected 34 Ground General purpose input output pins J6 and J7 are 2 54 mm pitch IDC headers that provide in total 16 digital pins Each digital pin can be configured as input or output The I O pins are filtered to a maximum switching frequency of approximately 50 kHz however the maximum I O switching rate is approximately 4 kHz In addition to the digital pins J6 provides one analogue output pin In addition to a fixed voltage between 0 and 5 V this pin can produce a wave signal at a frequency between 0 001 Hz and 10 kHz sine square triangle and sawtooth When configured as inputs the pins are TTL compatible with high impedance and weak pull up resistors When configured as outputs each pin either provides a TTL level signal or it can drive a LED or similar load like an opto coupler usually no external current limiting resistor is needed for driving a LED because each output pin is equipped with an internal current limiting resistor 220 Q The current limit depends on the LED s forward voltage it is 14mA at 2V The current for all the pins 16 digital combined may not exceed 160mA Because of the current limiting resistors outputs are TTL compatible only under the following conditions High level wecesesarticecoeseiegiar gt 2 V at lt 10 mA source VOW agen lt 0 8 V at lt 0 9 mA sink The triangle on
9. H0420 Programmable MP3 Audio Controller for Exhibitions and Kiosk Applications aa fk i E IE Pa oe g LED Connector LCD Connector ltra 25Bve F A Aalia CFlast User Guide ITB CompuPhase Tel 31 0 35 6939261 Eerste Industriestraat 19 21 Fax 31 0 35 6939293 1401 VL Bussum The Netherlands info compuphase com www compuphase com V 2009 05 05 C Rous COMPLIANT Table of Contents Pre UMN ANY eno a A A A crue wany elena tudes se stsabadscbecdumactausaedesdetautiuanes 2 Ansla handino Dire CAU MOUS icenian E a a a a a eluania 2 Powersopph volldde Tano Esne E E S ace ea rae eel ae eile 2 Eeoa ela ne e a a a A O E Co AES Se aC RIE BD Dee aE ae 2 Overview ofthe H0420 aiec A E O NERA 3 Conmecttne the G2 O vsieccisass vases vince vevease sissuee eve e a a eaaa e aiaa oaia N iii 3 CompactFlash CALC erren T O ENN 3 POWEP CONNCCIOR acna habe eee aa eat Seat ea 4 Adon S Sete nee Oe en nN ne aCe ee eee 4 Buton 06 01 6 eet a Dn SA nel EET 4 General purpose put output pissen at aa a ak eae Cet aise ada ei ela gia 5 CD CONNEC ODi aa a ar a a a aa sheateas sass Guanes 6 RS 2 apaa a E a anaes 7 Mechanical Montag e sicccsscsssceess soscsesse raat iwecsesdaventectad cata covatcteteatstann eo desewtanced aE aaa 7 Contents of the CD ROM vississiccstivecedoetscsscsccnssacsetvevestsdedaconessivasscesssebsesscvedeoucesesorseGeasvaruetinensedatcacesveasesss 9 Installing the development tools visissssisececsscessecccsseiades
10. and the peripherals The script must be written in the PAWN language and be stored in compiled form on the CompactFlash card under the name of AUTORUN AMX in the root directory In absence of a script the H0420 plays all MP3 files on the CompactFlash card in a random sequence To react on switches or I O pins and to communicate over RS232 or an optional LCD a PAWN script is required Connecting the H0420 Audio out Power RS 232 o m I O a Cun oO G91 O I CompactFlash card Connector K1 accepts CompactFlash cards types 1 and 2 The firmware supports cards formatted with FAT16 and FAT32 and it uses the first suitable partition The firmware supports subdirectories encrypted volumes partitions and encrypted MP3 tracks using strong encryption with a 128 bit key The CompactFlash card must contain all MP3 audio tracks Typically it will also contain a programmed script that determines how the device responds to various inputs for example by playing different audio tracks for each switch that is pressed Power connector The power connector is a standard low voltage power connector with a pin size of 2 1 mm The pin is the plus pole Heo Inverting the polarity damages the device Audio outputs Two RCA connectors provide analogue stereo output The red connector is for the right channel RCA connectors are
11. d lyrics frame was originally designed for purposes of karaoke and sub titling songs another use would be to tag time stamped cues or commands at specific positions 1n a song or audio fragment Adding synchronized lyrics to an MP3 file The first step in making a script react on synchronized events in an MP3 file is to attach an ID3 tag with the SYLT frame to that file Many ID3 tag editors are available both freeware and 12 commercial but only few support the SYLT frame that is needed for synchronized lyrics When choosing an D3 tag editor verify that it has the required capabilities Synchronized lyrics is a set of plain text strings where each string has a time stamp in milliseconds from the start of the audio track After having added the public function synch to your script this function will be invoked or called at the precise time stamps of each string and with the text of the string as a parameter For purposes of Karaoke the text strings will indeed be the lyrics of the piece For other applications the time stamped text may consist of strings like Close valve 1 or Next_ slide It is up to your script to interpret the text strings that it receives and to act upon them Encrypted MP3 tracks The H0420 supports MP3 tracks that are encrypted with 128 bit device key plus an optional 32 bit user key The device key is hard coded in the device only H0420 units with the correct key can play
12. e package Many of the tools also run directly from the CD ROM Using the ready made scripts You may first want to try whether one of the standard ready made scripts fits your requirements The ready made scripts are documented in HTML pages an links to these pages appear in the Program Files menu after installing the CD ROM The ready made scripts ready the audio tracks to play from a playlist that conforms to the WinAmp M3U specification The scripts may optionally be configured through a standard text file in INI file format All configuration options are described in the aforementioned HTML pages The ready made scripts may also serve as more advanced examples for coding your own scripts Each of the ready made scripts comes with the full and commented source code To use the scripts no programming or build step 1s required because the scripts come in a form that is directly usable by the MP3 controller pre compiled Writing scripts Scripts for the H0420 are in the PAWN language To type in and build the scripts you use the Quincy IDE that is part of the PAWN development tools or ans standard text editor When saving 66 29 the script s source code we suggest the extension p or pawn amp Quincy remotectrl p File Edit View Project Debug Tools Window Help Daeh amp 64 a amp i HPGe amp amp remotect p reScodes inc J reSdecode inc set up I O pin 11 for
13. eieucscessiadarivesedeiscdacacecscusssccsacvastasecduceteleossceweiseateiwes 9 Using the ready Mmades CH ts siciiessevordscts iasscaciveesssicisosaiebeiceeesevtacd naa teuauiessssvaetealabesicuves Wescsiavaaiesustedioaiens 9 WINES SCMIOUS esasa aeara aa a a a a Aaa 9 Further Pea TINS en a a ta hai lan Dae ld 12 Trams OTIS TCS exec cssasasersecisatovsivsuiasrs aaa dasavasveasttesuanediawearcuavoans savessbersaessonsundiectucnouatvesacseus 12 MP3 MIG ae GUITEMICIIS soi ccrieitedstieiateesedecsusentubheduaseedvsuanccssadcusaversdesanlsslseasadavensesinsaradisaluetedsstecesuaisitatessdee te 13 Track Guratiom amp seeking OA OSI OM scsi cates heath nea E EE r a a a a 13 IDS Tas and synchronized Even iaiia a E E E A EEE 13 Adding synchronized lyrics toan MP3 file scssseos5 stestige Sons ienn an E A AR ETR 14 Trouble shoo tinaren a E EA E E EE EEE 15 PC CHIC ALLO NS fescciirsesvianasscnduineerdawsvarssecanenadea ce a r EA raa Na AN AEE 16 E E EET E E EE A EE ANNE E E E EEE E A E E N N PE EE 16 A Oera A E MC A E E E A cteate ance sulle 16 CORO lenna a a a a R uaseaaeses 16 Mechanical osese a E E neesiaete aioe 16 Operaline condi ONS serren a S a ease a A eee 16 FIAN a O e a a a a E sasustees 16 Preliminary Anti static handling precautions Please observe anti static handling precautions when handling the device as it contains components that are sensitive to static discharges Power supply voltage range Please verify the power supply
14. et only runs on power up or reset of the device When and event occurs or the status of the device changes it invokes an appropriate public function In the case of the H0420 all public functions start with an symbol please see below for a list of available public functions This example script uses two public functions button is invoked on a switch press or switch release whether it concerns a press or a release is in the parameter status and audiostatus executes when the device starts or stops playing If you attach a LED between pins 14 and 15 this will light up when audio output is active in other words the LED is a busy indicator No resistor is required in from of the LED as the H0420 has internal current limiting resistors on all digital I O pins If a switch is pressed while the controller plays audio the controller switches to the new track aborting the current track There is an exception when the chosen track already plays the track will not restart from the beginning in this case As is apparent from the example script the PAWN language contains all common control constructs loops conditional execution compound blocks etc It also provides an assortment of native functions such as setiopin or play These are built in routines that the H0420 MP3 controller provides All native and public functions for the H0420 are documented in the H0420 programming
15. ltage See http www compuphase com mp3 for details Transferring files The FileLink utility on the CD ROM allows you to transfer files between the H0420 and a PC running Microsoft Windows over an RS232 connection After starting the FileLink utility the H0420 must be reset via the reset button a power cycle or a programmatic reset H0420 MP3 player controller Connection COM1 w Speed 230400 Filename Size Time a Bruce Springsteen 01 Old Dan Tucker mps 3237696 2006 06 03 16 37 24 2006 06 03 19 34 52 isc akorun ame 2472 2006 06 04 10 51 32 track 1 mp3 323088 2006 06 07 16 50 34 track mp3 323094 2006 06 10 15 33 04 playlist mau 1179 2006 08 12 18 06 32 n AgustinB arios M adrigal mp3 4382436 2006 08 12 16 14 24 The FileLink utility 11 MP3 file requirements Originally the abbreviation MP3 stood for MPEG version 1 Layer 3 audio For MPEG compressed audio there now exist various versions and the name MP3 denotes the class of MPEG layer 3 formats regardless of the version The H0420 is compatible with versions 1 2 and 2 5 in Layer 3 format Versions 2 and 2 5 of the MP3 format extend it to lower sampling frequencies and lower bit rates so that voice audio or low medium quality music could be compressed more compactly than with version 1 The H0420 does not support layers 1 or 2 of the MPEG audio format These formats have become obsolete Track duration amp
16. nector indicates pin see the picture 1 Ground Vss 2 Logic power supply 5V Vdd 10 O 3 LC driving supply Vo 4 Register Select RS O09 5 Read write R W 6 Enable E z 5 7 Data bit DBO 8 Data bit DB1 a 9 Data bit DB2 10 Data bit DB3 OO 11 Data bit DB4 12 Data bit DBS OO 13 Data bit DB6 14 Data bit DB7 5O O 15 Backlight power 5V A 16 Backlight ground K RS232 The device provides a standard 9 pin RS232 connector and it is configured as a DCE device Data Communications Equipment Internally the DTR and DSR lines are connected and the RTS and CTS lines are connected too A standard straight connection cable should therefore be suitable do not use a null modem cable The RS232 interface optionally supports the XON XOFF protocol software handshaking Hardware handshaking protocols are not supported The settings of the RS232 interface baud rate number of stop and data bits is controlled by the script on the CompactFlash card 5 1 i 6 Internally connected to pin 4 3 RxD Internally connected to pin 8 9 6 RS232 4 Internally connected to pin 6 8 Internally connected to pin 7 9 N C 5 Ground Optionally you can also use the RS232 to upload or download files to from the CompactFlash card using the FileLink utility see page 11 Mechanical montage Four mounting holes with a diameter of 3 1 mm suitable for M3 screws or s screws are spaced at 90 mm horizontally and 6
17. nything else than the line Start up the H0420 failed to read the CompactFlash card The text of the message tells you why the H0420 failed to read the card e g wrong file system 14 Specifications General Power input requirements 4 1 V to 5 5 V DC Current CONSUMPTION 0 cccceeeeeeees 140 mA with audio output 50 mA in stand by mode Storage MCCIUM ce eeeeececeeeeeeeeeees CompactFlash cards types 1 and 2 151k Gey Eo Dorene I O lines and pins are EMC filtered and ESD protected COn Ori o eea EN 55022 EN 55024 European Community RoHS Audio Frequency FeSPONSE cseseeseeeeeeeees 20 Hz to 20 kHz Dynamic range ccccccseccesseeeeeeceeeeeees 98 dB typical 1B ES 0 qi 0 cee ee re em ree THD lt 0 025 at 1 kHz NODE a SNR 98 dB typical Treble bass adjustment 0000000000000 software controlled configurable frequency and gain max attenuation enhancement is 18 dB Volume adjustment eeeccec eee eees software controlled max attenuation is 96 dB Output impedance eeeeeeeeeees 100 Q Output level nominal eee 1 5 V PUNOATNUG side ccciececraesiaecssducestinacesdnssacdsenats auto mute based on zero output detection Audio out CONNECHOFSS cccceeeeeeeeeeees 2 x RCA cinch Control IR S232 MCT AC Cs aenn a 9 pin D Sub connector configured as DCE standard I O signal levels Switch inputs eccccssssssseee sees 16 inputs equipped
18. reference Further reading For starting to script your H0420 the first book to reach for is the H0420 Programming Guide amp Reference Next to the documentation for all public and native functions this book also contains an assortment of programming examples ranging from simple to extensive 10 If you are new to the PAWN language the introductory chapter of the book The PAWN booklet The Language will give you a tutorial with example programs and a gentle introduction to programming This book also describes the error messages of the PAWN compiler with hints for how to fix the syntax or pointers to more information The Language Guide also contains the official specification of the PAWN language To connect the H0420 to other devices computers amplifiers sensors switches etc refer to the product s datasheet for hardware specifications and mechanical drawings The CompuPhase web site features an assortment of Application Notes describing special use and special extensions of the H0420 Examples of such notes are Introduction to programming the H0420 responding to switches Using a remote control for television and VCR to control the H0420 Synchronizing events with music using the D3 tag e Synchronizing the internal clock of the H0420 on the DCF77 or MSF time code Connecting the H0420 to a MIDI chain create or react on MIDI events Connecting an LCD that needs a negative LC driving vo
19. seeking to a position Within the format for MPEG Layer 3 audio there are the encoding varieties constant bit rate CBR variable bit rate VBR and average bit rate ABR The H0420 supports all three types For VBR and ABR files must have a Xing header to support direct jumps to a specific position in the MP3 track Without this header jumps to a position may be inaccurate for VBR and ABR files and the reported track duration is inaccurate as well Reported durations and direct jumps are always accurate for CBR files ID3 Tags and synchronized events The scripting language gives the programmer access to the information in an D3 tag version 2 with information on the artist album amp track full title copyright duration Details and informal standards of the ID3 tags are available on the web site http www 1d3 org The supported frames in the ID3 tag are Tag Description TIT2 Song title TPE1 Performing artist TALB Album title COMM Comment TCOP Copyright TYER Year TRCK Track on the album TLEN Duration of the audio track in milliseconds SYLT Synchronized lyrics In addition to the standard authoring information the H0420 supports the optional synchronized lyrics frame in the ID3 tag The contents in this frame will cause scriptable events to be fired on the time stamps that are attached to each line of lyrics Although the synchronize
20. the connectors indicate pin 1 see the pictures above and below 1 Ground 2 Logic power supply 5V 10 O 3 Analogue out 0 to 5V 4 108 Digital I O pin 8 cae 5 109 6 1010 z 5 7 100 Digital T O pin 0 8 IOI ee 9 102 10 103 one 11 104 12 105 OO 13 106 14 107 50 O 15 Power supply 5V 16 Ground The combination of all I O pins and the filtered power supply at pin 2 may draw 160 mA maximum Pin 15 of connector JP6 is connected directly to the power connector you can use this pin to draw higher currents 1 Ground 2 IOll 3 Ground 4 1012 5 Ground 6 1013 7 Ground 8 1014 9 Ground 10 1015 LCD connection Connector block J6 can serve as an LCD connector The pin lay out conforms to the standard LCD interface with HD44780 controller see the table below J6 is a 16 pin IDC header with a pitch of 2 54 mm Connector J6 provides either LCD driving function or eleven digital I O pins and one analogue output pin The choice between these two functionalities 1s software controlled The LC driving voltage on pin 3 is a software controlled voltage between 0 and 5 V LCDs that use a positive LC driving voltage Vo are directly supported LCDs that needs a negative LC driving voltage should use a voltage inverter on pin 3 When attaching a backlight unit to the connector on pins 15 and 16 you may need to put a resistor in the power line pin 15 In the H0420 pin 15 is connected directly to the power connector The triangle on the con
21. ut in the form of switches or digital levels from sensors Below is an example script that reacts on eight switches and plays a track in response to each switch In addition it configures I O pin 15 as output and toggles it on when playing a track and back off when playback stops Come Busy Pala 15 new Current I reset SOME TC ALOOaLin IBIS yi sabi OE oE CPurtron pin am eats feo die aillicsachy ollesaling elie Seliecinse ciel Gemoics ills bU Eon picasa 4 Pe Current pile eos Status current pin Swe Cla PIN Case Ua Olay eae k E mpo Case dey olay marae k sins CESS Yrs sola Uneevel eons Case 22 play Iracka mpo Gase Aa play era ekoa pS Casco pla Tako ines Gao des pLa AERA K po Case 72 pa tracks mpo GeichhLosice cue UMiichboOSineic 4 Giecinue 1f status Stopped Soop EUS T EO Uro nE else SeceroOoum BuscyP ua 1 The script starts by defining a constant BusyPin to indicate pin 15 Although not required it is good practice to give symbolic names to constants such as pin numbers Next 1s the definition of a global variable that holds the track currently begin played or 1 if none On power up the device will first execute the function reset this function is therefore the place to do any initializations In the above script it configures I O pin 15 as output and sets it to zero Function res
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