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By MAURO GRASSI Playback adaptor for CD-ROM drives; Pt.2 Last month, we published the circuit details of our new CD-ROM Player Adaptor and described its operation. This month, we show you how to build it. to be installed. Before installing any parts though, it’s a good idea to inspect the PC board for hairline cracks in the tracks or shorts. Some of the tracks are very fine and quite close together, so check these carefully. T Installing the wire links O KEEP COSTS DOWN, we’ve designed a single-sided PC board for this project. This board is coded 07112071 and measures 136 x 97mm. The complete board and the CD-ROM drives could optionally be encased in 90  Silicon Chip a plastic case or mini-tower computer case, along with the power supply. Because it’s single-sided, the PC board is somewhat larger than a double-sided board would be and there are quite a few wire links that have Fig.2 shows the locations of the wire links and these should all be installed first. Because some of these links are quite close together, it’s essential that they be perfectly straight so that they siliconchip.com.au Fig.2: the first job in the assembly is to install all the wire links as shown here. Make sure that these links are straight, to prevent shorts – see text. Programming The Microcontroller don’t short together. The best way to straighten the link wire is to stretch it slightly by clamping one end in a vice and pulling on the other end using a pair of pliers. Each wire link can then be cut to length and its ends bent down at right-angles using needle-nose pliers before mounting it on the PC board. Once you’ve completed this task, you’re ready to install the remaining parts. Fig.3 shows the parts layout on the board. Start with the resistors, taking care to ensure that the correct value is used at each location. Table 1 shows the resistor colour codes but it’s also a good idea to check each one using a digital multimeter before soldering it to the PC board. Next, solder in protection diode D1, making sure that it is oriented correctly, then install the small tactile switch (S3). The latter only fits correctly if it is the right way around. The next step is to solder in the 40siliconchip.com.au IF YOU PURCHASE a kit, then the microcontroller will be supplied preprogrammed. If not, then you will have to program it yourself. To do this, you will need to install both IC4 & IC5 (MAX232), as well as the other two logic ICs. You then load the hex file into Pony Prog 2000 and write to flash. If you don’t already have this program, it is available as a free download from www.lancos.com/ppwin95.html You will need to first flick switch S1 and make sure the orange LED lights up. The micro is then ready to be programmed. We should also mention that if you are using Pony Prog 2000, you must change the setting under Setup -> Interface Setup and make sure that the only box that is ticked is the “Invert Reset” box. Then select the correct device by going to Device -> AVR -> Atmega8515. Prior to programming, Pony Prog 2000 needs to be calibrated for correct timing. To do this, simply go to Setup -> Calibration. This only needs to be done the first time you run Pony Prog 2000 on a new computer. Now choose File -> Open Program (FLASH) File and select your hex file. Go to Command -> Program (FLASH) and Pony Prog 2000 should start programming your micro. Once programming is complete, you should flick switch S1 so that the orange LED goes out and then the firmware should start running. pin IC socket for the microcontroller, plus the two 14-pin and two 16-pin DIP sockets for the other ICs. Note that only IC1, IC2 and IC3 are required for normal operation, while IC4 and IC5 are required only if you are planning to program the micro via this board. Make sure that the sockets are all oriented correctly – ie, with their notched ends oriented as shown on Fig.3. The TO-220 regulator is next on the list. As shown, this part is fitted with a small heatsink and is mounted horizontally on the PC board. December 2007  91 This view shows the fully assembled prototype PC board. Note that the two MAX232 ICs and the DB9 socket (CON3) are only necessary if you intend programming the microcontroller on the board. If you buy a kit, the microcontroller will be supplied pre-programmed. Note also that trimpot VR1 (contrast) and several wire links were added to the board after this photo was taken. The correct procedure here is to first bend the regulator’s leads down though 90°, exactly 5mm from its body. That done, the device and its heatsink are fastened to the PC board using an M3 x 10mm screw and nut. The leads are then soldered. Don’t solder the leads before bolting the device to the PC board. If you do, you could stress and break the PC tracks as the device is tightened down on the board. Trimpot VR1 can go in next, followed by the 2.5mm DC socket (CON6) and the electrolytic capacitors. The latter are polarised, so make sure they go in the right way around. Now solder in the 100nF bypass capacitors. Take particular care with the 100nF capacitor immediately to the left of IC1. It straddles a couple of wire links and should be mounted proud of the board so that its leads don’t short against these links. The other 100nF capacitors can be pushed all the way down onto the board. The five LEDs (LEDs1-5) and the infrared receiver module (IRD1) can now be installed. As shown in the photos, the LEDs all go in with their leads bent at right angles and are mounted about 5mm proud of the PC board. A cardboard spacer cut to 5mm makes a handy gauge when it comes to bending the LED leads and spacing them evenly off the board, so that they all line up. Take care to ensure that the LEDs all go in the right way around. Just remember that the anode lead is always the longer of the two. IRD1 can be mounted so that its lens lines up with the centres of the LEDs. It must be oriented so that its lens faces out from the PC board. Installing the headers The next job is to solder in the 16- Table 2: Capacitor Codes Value mF Code IEC Code EIA Code 100nF 0.1mF 100n 104 22pF    NA     22p   22 Table 1: Resistor Colour Codes o o o o o No. 1 5 1 1 92  Silicon Chip Value 1kW 470W 100W 51W 4-Band Code (1%) brown black red brown yellow violet brown brown brown black brown brown green brown black brown 5-Band Code (1%) brown black black brown brown yellow violet black black brown brown black black black brown green brown black gold brown siliconchip.com.au Fig.3: after the links are in, install the remaining parts on the PC board as shown here. Take care to ensure that all polarised parts, including the IDC headers, are correctly oriented – see text. pin and 40-pin IDC headers. Pin 1 of each of these is indicated by an arrow on the side of the header and this corresponds to the square pad on the PC board. Be sure to get them the right way around. In each case, it’s a good idea to initially solder just two pins of the header and then check that it is sitting flat against the PC board. After that, it’s a routine job to solder the rest of the pins. Finally, complete the PC board assembly by installing the 7.3728MHz crystal (it can go in either way), the two 22pF capacitors, the DB9 serial port connector (CON3), the two stereo jack sockets (CON8 & CON10), the two 4-way SIL pin headers (CON7 & CON9) and the two toggle switches. Fig.4: this diagram shows how to connect the Altronics Z-7013 LCD module to the 16-pin IDC socket. Note that pins 15 & 16 (the backlight connections) are adjacent to pin 1. Pin 15 is the anode connection, while pin 16 is the cathode. Connecting the LCD module The LCD module to use must conform to the Hitachi HD44780 industry standard. This has an interface consisting of 16 or 14 lines, depending on how the LED backlight is connected. A 16-way (or 14-way) ribbon cable is used to make the connection to the siliconchip.com.au December 2007  93 Fig.5: connect the Jaycar LCD modules as shown in this wiring diagram. Note particularly that the wires from pins 1 & 2 of header CON2 are transposed at the LCD module (ie, pin 1 goes to pin 2, while pin 2 goes to pin 1). Fig.6: assigning the buttons on the remote for the various functions is easy – just follow the prompts on the LCD readout. This is the prompt for assigning the “Volume Up” button. In particular, note that pin 1 on the Jaycar modules is the +5V connection, while pin 2 is the 0V connection. It’s the other way around on the Altronics module, where pin 1 is 0V and pin 2 is +5V. Testing & troubleshooting LCD module and this is terminated at the other end in a 16-way IDC line socket, with the red stripe on the cable going to pin 1. This end then plugs directly into the 16-way IDC header on the PC board. Fig.4 shows the connections to the Altronics Z-7013 LCD module. This device has 16 pins all in one line along the bottom edge of the board (although pins 15 & 16 are adjacent to pin 1). Alternatively, the Jaycar QP-5516 and QP-5518 LCD modules each have a 2 x 7-pin arrangement at one end; ie, there are only 14 connections. The backlight connections are made on the module itself, so pins 15 & 16 of CON2 are not connected in this case. Fig.5 shows the wiring connections for the specified Jaycar modules. The audio output at the back of a CD-ROM drives can be connected to CON7 or CON9 via a standard 4-way cable fitted with matching headers. These cables are readily available from computer stores or you can make your own. 94  Silicon Chip Great care has been taken to ensure that the firmware is free from bugs but we cannot guarantee that it will work with every CD-ROM drive. We did test the board with six different CD-ROM drives and it worked well. The only problem was that two of the drives did not respond to the volume change command. However, we are not sure that these two drives were actually functioning correctly all of the time, as they appeared to have intermittent faults. Whichever drive you want to use for this project, make sure it is an ATAPI device (check that the IDC connector on the back of the drive has 40 pins, as opposed to 50 pins for a SCSI connector). Note also that the adaptor will not work with some smaller form factor CD-ROM drives which have 44pin connectors (akin to the 2.5-inch notebook hard drives). Before plugging in the micro (IC1), the first thing to do is to check the power supply rails. To do this, first connect a 9-12V DC plugpack to the DC socket (CON6) and switch on. That done, check that the OUT terminal of REG1 is at +5V with respect to ground. Fig.7: 4-way headers CON7 & CON9 are connected to the two 3.5mm stereo jack sockets. This makes it easy to connect to the CD-ROM drive audio outputs via a standard stereo jack plug. siliconchip.com.au Table 3: CON2 Pin Assignments Pin Pin Name 1 VSS Supply rail for module; typically GND 2 VDD Supply rail for module; typically +5V 3 V0 Set LCD contrast 4 RS RS = 0 selects instruction; RS = 1 selects data 5 R/W R/W = 0 selects write; R/W = 1 selects read 6 E E = 1 selects the LCD module 7 D0 Data bus bit 0 8 D1 Data bus bit 1 9 D2 Data bus bit 2 10 D3 Data bus bit 3 11 D4 Data bus bit 4 12 D5 Data bus bit 5 13 D6 Data bus bit 6 14 D7 Data bus bit 7 15 A LED backlight anode 16 K LED backlight cathode Parts List: CD-ROM Controller Description Similarly, you should be able to measure +5V on pin 40 of the 40-pin socket, while pin 20 should be at 0V. If these checks are OK, switch off and plug in the micro. Make sure that this device is oriented correctly and that all its pins go into the socket. In particular, take care to ensure that none of the pins are folded back under the device. That done, set trimpot VR1 to midrange and switch on again. Check that the LCD module initialises correctly, then adjust VR1 for optimum display contrast. Remote control functions The firmware has an option that allows you to use any RC5 protocol remote control. That means that you can use virtually any universal remote control plus most of the remotes that are commonly used with TV sets, VCRs and DVD players The first step is to assign the buttons that will control the various functions. To do this, you first need to press and hold the “Remote Program” button (S3) while the device resets. To get the device to reset, you toggle switch S1 so that the orange LED lights and then toggle it again to turn the LED siliconchip.com.au 1 PC board, code 07112071, 136 x 97mm 1 16x2 backlit LCD module (Jaycar QP-5516 or QP-5518, Altronics Z-7013) 1 PC-mount 40-pin IDC header (CON1) (Jaycar PP-1114, Altronics P-5040) 1 PC-mount 90° 16-pin IDC header (CON2) (Jaycar PP-1122, Altronics P-5066) 1 PC-mount DB9 female RS232 socket (CON3) (Altronics P-3050, Jaycar PS-0804) (optional for programming) 1 28-pin or 40-pin SIL header strip (Jaycar HM-3211, Altronics P-5430) 1 16-way IDC ribbon cable (to connect LCD module, length to suit) (Jaycar WM-4502, Altronics W-2616) 1 40-way IDE HDD cable (to connect CD-ROM drives) 1 16-way IDC line socket (Jaycar PS-0985, Altronics P-3516) 2 3.5mm stereo sockets, PC-mount (CON8,10) (Altronics P-0094) 1 2.5mm DC socket, PC-mount (CON6) (Jaycar PS-0520, Altronics P-0621A) 1 PC-mount micro tactile switch (S3) (Jaycar SP-0600, Altronics S-1120) 2 SPDT 90° PC-mount toggle switches (Altronics S-1325) 2 16-pin IC sockets (optional for programming) 1 40-pin IC socket 2 14-pin IC sockets 1 TO-220 mini heatsink (Jaycar HH-8502, Altronics H-0630) 1 7.3728MHz crystal (X1) 1 10kW horizontal trimpot (VR1) 1.5m tinned copper wire for links 1 M3 x 10mm machine screw 1 M3 nut Semiconductors 1 ATMega 8515 microcontroller programmed with CDATA.hex (IC1) 1 74LS00 quad NAND gate (IC2) 1 74LS04 hex inverter (IC3) 2 MAX232 RS-232 transceivers (IC4,IC5) (optional – see text) 1 infrared receiver module (IRD1) (Jaycar ZD-1952, Altronics Z-1611) 1 7805 3-terminal regulator (REG1) 1 1N4004 silicon diode (D1) 2 3mm green LEDs (LED1,LED5) 2 3mm red LEDs (LED2,LED4) 1 3mm orange LED (LED3) Capacitors 2 47mF 16V electrolytic 1 10mF 16V electrolytic 10 1mF 63V electrolytic (optional for programming) 4 100nF monolithic 2 22pF ceramic Resistors (0.25W, 1%) 1 1kW 1 100W 5 470W 1 51W Power Supply Options LAST MONTH, we stated that one of the supply options for the board was to plug a computer power supply into either CON4 or CON5. We have since decided to scrap that option and now recommend that you stick to powering the board from a 9-12V DC plugpack. The disk drives can be powered directly from a computer power supply. Alternatively, if you don’t want the fan noise of a computer power supply, you can use a mains adaptor like the Jentec JTA0202Y. This unit supplies +12V and +5V rails at 2A each which is enough to power two drives and comes with the correct plug (you’ll need a Y-splitter cable to power two drives). At the moment, you will have to purchase this adaptor via eBay but it may be available from Altronics and Jaycar in the near future. off (ie, you hold S3 down while you toggle S1 twice). This resets the micro and takes you to the “Setup Remote” screen. Here you can program the keys to be used for the project. The device will guide you December 2007  95 Here’s another view of the assembled prototype PC board, this time hooked up to an LCD module that we happened to have on hand. Note that after the unit has been built, you have to assign the remote control functions – see text. through the set-up, and the keys that you define will be stored in EEPROM for later use. For example, when the screen displays “Press Vol Up” (see Fig.6), you simply press the “Volume Up” button on your remote. It’s just a matter of cycling through all the options until the button assignment has been completed. This means that you can use any spare RC5 remote and define the keys as you see fit. The “Power” button is deliberately unused for this project and this lets you control the device with your TV remote control, for example. In other words, because the “Power” button is unused, you can have your TV off and use its remote to control the CD-ROM Player Adaptor. Then, when you are finished with the adaptor, you can switch it off and use the remote to control your TV again. Of course, you won’t be able to play a CD and watch your TV simultaneously using the same remote but this feature can keep costs down. It means that you don’t have to purchase a separate universal remote control, although you can if you wish. Operation The user interface has been kept quite simple. Occasionally, issuing a command will result in an error screen. This is perfectly OK as the firmware has been designed to be quite tolerant of errors. If it happens, simply try the command again but if the problem persists, it may indicate an incompatibility or fault with your drive. The “Error” screen typically looks like that shown in Fig.2 last month but may have different numbers which are used for debugging purposes. The hexadecimal numbers give an indication of the state of the ATA registers and the state machine when the error occurred. If the errors consistently re-occur, this information will help to diagnose SC the problem. Issues Getting Dog-Eared? Keep your copies safe with these handy binders REAL VALUE AT $13.95 PLUS P & P These binders will protect your copies of SILICON CHIP. They feature heavy-board covers & are made from a dis­tinctive 2-tone green vinyl. They hold 12 issues & will look great on your bookshelf. Available Aust only. Price: $A13.95 plus $7 p&p per order (includes GST). Just fill in and mail the handy order form in this issue; or fax (02) 9939 2648; or call (02) 9939 3295 and quote your credit card number. 96  Silicon Chip siliconchip.com.au