How To Build Megavolt s Small Buffered JTAG v1.2

How To Build Megavolt s Small Buffered JTAG v1.2 Abstract A JTAG cable should be considered mandatory equipment for any serious tester. It provides a means to backup the information in the receiver and restore it whenever necessary. This document illustrates the process of building one that is safe to use in any receiver. An illustrated guide by DO999 Revised August 20 th, 2002 Version 1.01 DO999 @ www.dssword.com or DO999 @ www.sattech.net

Preface... 1 Introduction... 1 Assumptions... 1 Electrical Schematic by SatFTA... 4 Construction General... 5 Construction of the JTAG module... 5 Step 1: Initial assembly of the PCB.... 5 Step 2: Mount (solder) the main components... 6 Step 3: Connect the parts together.... 7 Step 4: Add the single 100 Ohm resisitors... 8 Step 5: Creating a grounding strip... 9 Step 6: Connect wire for Vcc (power) and Ground to the circuit... 9 Step 7: IRD JTAG Port Connection... 10 Step 8: Computer (PC) Connection... 11 Step 9: Completion of JTAG module.... 12 Installation... 13 Installation - PC Connection... 13 Mounting the DB25... 14 Installation - Connecting to the IRD... 14 Installation - Power Connection... 15 Optional PAD 1 Grounding Switch... 15 Installation Internal Mounting... 16 Conclusion... 16 Troubleshooting... 16 Appendix A Images... 17 Internal JTAG for a 3100... 17 Standalone JTAG that can be used on any IRD... 18 IRD JTAG Connection Images... 19 Model 2700... 19 Model 3100 / 301... 19 Model 5100 / 501... 21 Model 6000... 21 Appendix B Detailed Parts List... 22

Preface The first thing I want to point out is that this guide is nothing more than an assembly guide. The credit for the actual circuit design goes to SatFTA. These instructions expand on the Megavolt s Small Buffered JTAG v1.2 documents by adding step-by-step pictures and some alternative construction techniques. All the real credit belongs to those SatFTA and MegaVolt. Second, I want to mention that the document is fairly long but hopefully that is due to the level of detail I am putting into it. This project really is fairly simple to construct. Many sections will not apply to you and the JTAG that you will build. You should of course read the entire document before starting construction. This will allow you to get the necessary parts and have a good understanding of the options available to you. Introduction Megavolt set out to create a buffered JTAG without a Printed Circuit Board (PCB), small enough to fit inside a DB25 housing. He was quite successful and the design was brilliantly simple. This guide expands on that by adding in the PCB such that it can be mounted inside the IRD case or a small project box. Examples, information and pictures of various optional parts and mounting techniques will be shown later in this guide. Assumptions It is assumed that the reader has a basic level of soldering skill. The construction is fairly straightforward and with the PCB a beginner should be able to accomplish the task. Knowledge and understanding of electrical diagrams is not required even though they are included in the guide. It is also assumed that you have read Megavolts documents as they provide some details and background that I do not. Some of the information presented here is directly from that document. How to build Megavolt s Small Buffered JTAG v1.2 by DO999 Page 1

Purpose In general, the purpose of any JTAG cable (buffered or not) is to read and write the TSOP chip within the receiver (IRD). The most common reason for using the JTAG is to extract the BoxKey information from the IRD. Once you have the BoxKeys, you are able to test options that do not require the use of the smartcard (CAM) such as the Atmega128 or computer emulation software. This connection also allows you to create backup images of the firmware within the unit. The firmware is the program code that basically makes the unit work. It is the equivalent to the operating system that you load onto a computer. Being able to read / write the firmware is important to recover from ECM s or to roll back the firmware to a previous version that may not have anti-testing features in it (like firmware version E338 on the 3100 IRD). In addition, with great software like JKeys by Dave2 you cannot only backup the TSOP (or TSOPs since x100 series IRDs have more than one chip) but you can also read and write the EEPROM chip through the same cable and software. (Note: Wall version 2 also works great on the 3100) If you have read this far you probably already know why you want to build a buffered JTAG. Just in case, the brief rundown is that the buffered JTAG supplies data signals and voltages that are friendly to both the IRD (receiver) and the computer. The simple resistor style JTAG can use in excess of 5V which is greater than the 3.3V used in the TSOP the x100 series IRD and not only can it result in poor reads / writes but it can significantly damage the TSOP. This is not to say that it will absolutely happen, just that it could. The use of a buffered JTAG alleviates these issues. The resistor style JTAG (which I won t get into here) is great on the x700 (and I m sure other types) series IRD. Personally, I had nothing but troubles with the simple JTAG on a 3100 and that is when I was converted and jumped on the buffered JTAG bandwagon. How to build Megavolt s Small Buffered JTAG v1.2 by DO999 Page 2

Parts List A detailed parts list, with pictures, is included in the appendix to this document. Part numbers, approximate cost and supplier information can also be found in the appendix. In summary, the following parts will be used: Quantity Description 1 74HCT244 Octal 3-state noninverting line receiver chip 1 2.2K Ohm Bussed 9 resistor network (10 pin Single Inline Package[SIP]) 2 100 Ohm Isolated 4 resistor network (8 pin SIP) 2 100 Ohm resistor 1 Printed Circuit Board (PCB) 1 DB25 Connector Male or Female depending on your PC parallel cable 1 6 strip of 6 or 10 conductor ribbon wire. (An old floppy cable works well.) 1 (Optional) DB25 housing Used if you are not mounting the JTAG inside the IRD 1 (Optional) SPDT or SPST switch Used for Power On/Off 1 (Optional) SPDT or SPST switch used to ground Pad 1 on some IRD s. Also a momentary contact switch (push button) works well for this. 1 (Optional) 20-pin socket to mount the 74244 chip not required if you solder the chip directly to the PCB 1 (Optional) SIP socket strip with 26 pins not required if you solder the resistor networks directly to the PCB 1 (Optional) Plastic project box required if you are making a portable, external JTAG 6 (Optional) Pogo / Spring pins to connect to IRD JTAG port. Not required for directly soldered cabling. 1 Miscellaneous length of wire, solder, glue or other mounting material 1 (Optional) 3.3V (3.0V to 3.6V) power source. Battery or transformer. Not required for internally mounted JTAG. [2 x AA batteries for an x100 series or 3 x AA batteries for a x700 series IRD work well] An internally mounted JTAG using only the mandatory items listed above will run about $10-$15 Canadian. Obviously, the more optional parts that are used, the higher the cost. How to build Megavolt s Small Buffered JTAG v1.2 by DO999 Page 3

Electrical Schematic by SatFTA Here is the overall design of what we are trying to make. If you can follow the directions, it is not necessary to understand this drawing. A simplified drawing mapped onto the board layout would look like this: How to build Megavolt s Small Buffered JTAG v1.2 by DO999 Page 4

Construction General The Buffered JTAG consists of the PCB with the various resistors and 74244 chip mounted on it. The connection to the PC DB25, the JTAG port and power will be described as part of the Installation process. Construction of the JTAG module Once again I want to emphasize that these steps are essentially the same as those published by Megavolt with the addition of a PCB. I also chose to build the JTAG using sockets for the components because that is the way I was taught and the pictures are easier to view with them. It is also easier to replace the parts or borrow them for other projects. The main reason for using sockets is to prevent damage to the components from over heating during soldering. Sockets are not required and add to the overall cost of the project. Feel free not to use them. Step 1: Initial assembly of the PCB. Trim (ie cut) legs (pins) 2, 3, 5, 7 & 9 off the 2.2K Ohm resistor network or the SIP socket as shown below. These pins are not required and will get in the way later if not removed. Note that Pin 1 of the resistor network is typically on the left side when viewing the side with printing on it and should be marked with a coloured band or other indicator such as a dot or triangle. How to build Megavolt s Small Buffered JTAG v1.2 by DO999 Page 5

Step 2: Mount (solder) the main components Start by placing the 74244 chip or the 20-pin socket in the middle of the PCB to allow for other components to be located around the chip. Align the resistor networks or SIP sockets as indicated in the picture. Note the resistor networks/sip sockets should be mounted right beside the 74244 chip or 20-pin socket and not as shown. The image simply shows the alignment. See the next image for actual placement. The image below shows the correct placement of the chips / sockets as viewed from the top of the PCB. On the back side of the PCB, solder all pins to the connection points on the PCB but do not bridge solder between any of the pins at this time. There should be 20 solder connections for the 20-pin socket, 5 solder connections for the 10-pin SIP socket (2.2K resistor network) and 8 solder connections for each of the two 8-pin SIP sockets (100 Ohm resistor networks). How to build Megavolt s Small Buffered JTAG v1.2 by DO999 Page 6

Only 5 connection are required for the 2.2K Ohm resistor network because you removed the other unused pins. Step 3: Connect the parts together. Use solder on the back side of the PCB to bridge a circuit between pins 1, 4, 6, 8, 10 of the 2.2K Ohm bussed resistor network and pins 20, 17, 15, 13, 11 of 7444 chip or socket respectively as indicated in yellow below. ie Pin 1 of the resistor network connects to pin 20 of the 74244, pin 4 to pin 17 and so on. Using the same technique extend the solder from pins 4, 6, 8, 10 of 2.2K Ohm resistor network to the adjacent pins (1, 3, 5, 7) of the 100 Ohm resistor network creating a connection across all 3 pins. On the other side of the 74244 chip connect pins 3, 5, 7, 9 to pins 1, 3, 5, 7 of the second 100 Ohm resistor network. How to build Megavolt s Small Buffered JTAG v1.2 by DO999 Page 7

Step 4: Add the single 100 Ohm resisitors. Solder a 100 Ohm resistor to pin 2 of the 74244 chip and a second 100 Ohm resistor to pin 18 of the 74244 chip. Note: When installing the resistor connected to pin 18, leave the wire (lead) on the resistor fairly long as you will connect it past the 2.2K resistor network as shown below. Once it is in place, trim the excess wire off with a pair of cutters. How to build Megavolt s Small Buffered JTAG v1.2 by DO999 Page 8

Step 5: Creating a grounding strip Connect pins 1, 4, 6, 8, 10, 19 of 74244 chip together to form a common grounding point. Use a piece of solid wire and solder it between the pins listed. Make sure the wire does not come in contact with anything else. I left the ground wire long in the image in case I wanted to use it later in the construction process. Step 6: Connect wire for Vcc (power) and Ground to the circuit In preparation for connecting power to the circuit, add a red (Vcc) and black (ground) wire (or any colour) connecting Vcc to pin 20 of the 74244 chip and the ground to pin 1 or the grounding strip created in the previous step. Optionally, the Vcc line can be connected to a power switch if you are using a battery so that the circuit can be powered off to the save the life of the battery when not required. How to build Megavolt s Small Buffered JTAG v1.2 by DO999 Page 9

Step 7: IRD JTAG Port Connection A 6-wire or 10-wire ribbon cable can be used to connect to the JTAG port on the IRD. This may be soldered directly to the IRD or may be connected via the optional pogo pins. Ultimately, you want this portion or the circuit to be as short as possible. For now, ensure that you will have plenty to work with as you can easily make it shorter later on. If using a 10-wire ribbon cable, connect every second wire to the ground line (not shown). By grounding every second wire you are in effect isolating the signals in the ribbon cable and reducing any noise picked up by the wiring. This makes the signal cleaner and reduces the potential for problem reads or writes. Connect one wire to the grounding strip, four wires one to each of pin 2, 4, 6 & 8 of the 100 Ohm resistor network and the 6 th wire to the single 100 Ohm resistor. How to build Megavolt s Small Buffered JTAG v1.2 by DO999 Page 10

Step 8: Computer (PC) Connection Similarly on the other side of the chip you need to connect a cable (such as Cat 5 network cable) to the circuit. A DB25 connection will be installed later and this will be connected to the parallel port on your computer. Connect one wire to pin 19 of the 74244 chip, one wire to the 100 Ohm resistor and the remaining 4 wires to pins 2, 4, 6 & 8 of the 100 Ohm resistor network as indicated. Note, when connecting to pin 19 of the 74244 chip, skip over the contact for the 2.2K Ohm resistor network. You should have cut that pin off at the beginning so it will not be a problem. You may alternatively connect this wire to any other convenient grounding point. How to build Megavolt s Small Buffered JTAG v1.2 by DO999 Page 11

Step 9: Completion of JTAG module. If you used sockets, you may now insert the 3 resistor networks and the 74244 chip. This marks the end of the basic module construction. All that is left is to connect it up. Trim the PCB and mount it inside the project box if one is going to be used. How to build Megavolt s Small Buffered JTAG v1.2 by DO999 Page 12

Installation Installation - PC Connection A DB25 connector (25-pin) is used to interface to the computer as mentioned previously. This connection will plug into the parallel port on the computer. If you already have a cable on this port then the easiest thing to do is install the corresponding DB25 connector. For example, I have a 25-pin male-to-female straight through cable attached to my parallel port already so I wanted a male DB25 for it to plug in to. There are different types of DB25 connectors. The simplest one is a solder type where you solder the wires onto terminals in the DB25. I used a crimp connector type for mine since I had the parts and crimper tool handy. That is what you will see in the pictures. As indicated below, you need to connect the wires from pins 8, 6, 4 & 2 of the 100 Ohm resistor network to corresponding pins 2, 3, 4, & 5 of the DB 25 connector. Additionally, connect the 100 Ohm resistor to pin 13 of the DB25 and connect a ground wire to pin 25 of the DB25. Important Note: If you need to pass the wiring through a hole in the IRD, the project box or anything else, do so before connecting the DB25. How to build Megavolt s Small Buffered JTAG v1.2 by DO999 Page 13

Mounting the DB25 If you are making a stand alone JTAG that will be used on more than one IRD then you probably want to mount the PCB inside a small plastic project box. You could mount the DB25 directly into the wall of the box or drill a hole for a wire and put the DB25 into a housing that you can purchase for a professional look. Similarly, if you are mounting the JTAG inside an IRD you can mount the DB25 in a slot cut into the casing of the IRD or drill a hole to pass the wire through the case and put a housing over the DB25. Cutting a slot for the DB25 in the IRD case can be difficult. Installation - Connecting to the IRD Connecting the ribbon cable to the JTAG port on the IRD can be tricky because not all IRD s have the same configuration and the pinout may change between revisions. However, the basic concept remains the same. You need to connect the ribbon cable to the TMS, TCK, TDI, TDO, ntrst and Ground lines of the IRD. The following chart has been included (thanks to SatFTA) but you should check for a newer version on the internet if your specific model is not included. Additionally, there are a number of ways to connect the ribbon cable to the JTAG port. I built a buffered JTAG that I can use on any IRD (that has a port) by connecting the ribbon cable to pogo pins. This is similar to the commercial ones that you can purchase. How to build Megavolt s Small Buffered JTAG v1.2 by DO999 Page 14

My prototype was built using the connector from a commercial JTAG, I simply cut the ribbon cable and connected it to my circuit. The second one I built from scratch. I marked the position of the JTAG pads on a piece of paper and drilled holes into a piece of wood that the pogo pins could fit into. I then used a hot glue gun to build up a block of glue around the pins, which I could shape with a knife and the glue gun. It fits perfectly into the existing opening in the IRD. The 3100 (and 5100) take considerably longer to read / write than the 2700 I started on so I decided to mount a JTAG into the 3100 on a permanent basis. This one I wired directly to the top of the motherboard and I cut a slot into the back casing for the DB25. This section may seem a little vague, but I will leave it up to you to decide how you will connect to the IRD. Pogo pins and direct wiring both have advantages and disadvantages. Installation - Power Connection The 74244 chip requires power for the circuit to function. If you are building an external JTAG then the use of a battery or power transformer is necessary. In the two external types that I built I used a 3.5V lithium battery. I installed a switch so that I could power on the circuit only when required to save battery life. If you use a transformer, simply unplug the transformer to cut power, no switch required. On the internally mounted JTAG I found a 3.3V connection on the motherboard (positive (+) side of a capacitor) that I used to power the circuit. I did not see the need for a power switch since powering the circuit should not affect normal operation of the IRD. I connected to capacitor C137 but there are a number of available connection points. A ground point is easy to find. Connect to the side of the casing if you are in doubt Voltages between the range of 3.0V and 3.6V should be fine for the circuit to function normally. Optional PAD 1 Grounding Switch A switch can be used to created a ground connection for Pad 1 on the x700 series IRD s. If the switch is used (on) when A/C power is applied the IRD boots up into a service mode permitting writes to the TSOP. This is particularly useful for internally mounted JTAGS. How to build Megavolt s Small Buffered JTAG v1.2 by DO999 Page 15

Installation Internal Mounting If you are installing the module internally, you can use the same type of plastic standoff that is used to mount a motherboard for a computer into a case. A local computer store will probably provide you with a couple at minimal or no cost. Simply trim the plastic tabs to make a flat foot for the module to sit on. Use cable ties to secure the wires to the module and the case. You don t want them lose inside the IRD. Conclusion Now that the JTAG is built and installed, grab a copy of JKEYS (version 2.01 is current as of the time this document was prepared). Grab your BoxKeys and a backup of your TSOPs and EEPROM. You will be able to sleep better at night knowing you can restore these whenever necessary. Troubleshooting An excellent troubleshooting guide can be found at http://www.kickinchicken.org/phpbb2/viewtopic.php?t=445. I hope this link stays active for a while. How to build Megavolt s Small Buffered JTAG v1.2 by DO999 Page 16

Appendix A Images Internal JTAG for a 3100 The following image shows the mounting and connection points (in general) of the JTAG built to connect to the top of the 3100 motherboard and using a slot cut in the case for the DB25 PC connection. How to build Megavolt s Small Buffered JTAG v1.2 by DO999 Page 17

Standalone JTAG that can be used on any IRD This image shows a battery powered JTAG with pogo pins that can be used on any IRD that has a standard JTAG port. How to build Megavolt s Small Buffered JTAG v1.2 by DO999 Page 18

IRD JTAG Connection Images The following images show the Pad configuration for a number of IRDs. Model 2700 Note: The 2 images have reversed front / back from each other. Model 3100 / 301 The 3100 has a number of different pin configurations so match the image to your IRD. How to build Megavolt s Small Buffered JTAG v1.2 by DO999 Page 19

It is also possible to connect to the inside of the 3100 IRD on the top of the motherboard at the EJTAG port. Note that the connection configuration is completely different from the underside connections. How to build Megavolt s Small Buffered JTAG v1.2 by DO999 Page 20

Model 5100 / 501 Model 6000 How to build Megavolt s Small Buffered JTAG v1.2 by DO999 Page 21

Appendix B Detailed Parts List Most of the parts can be found at an electronic store or on the Internet at www.digikey.ca. The PCB is a Radio Shack part and the Pogo pins were obtained from www.solarbotics.com. Detailed Parts List Qty Description Image 1 74HCT244 Chip Part No: SN74HCT244N Alternate Parts: 74HC244 Cost: $1.99 1 2.2K Ohm Bussed 9 resistor network (10 pin SIP) Part No: 4610X-101-222 (2 per package) Cost: $1.49 per package 2 100 Ohm Isolated 4 resistor network (8 pin SIP) Part No: 4608X-102-101 (4 per package) Cost: $1.49 per package 2 100 Ohm resistors Part No: 1/4W-100R-5 (5 per package) Cost: $1.49 per package Alternate Part: 1/2W resistor as shown. 1 3.3V Power Source (Optional) Battery or Transformer 2 x AA batteries (3.0V) or 3 x AA batteries (4.5V) can also be used. How to build Megavolt s Small Buffered JTAG v1.2 by DO999 Page 22

Qty Description Image 6 Pogo (Spring) Pins (Optional) Part No: PP3 Alternate Parts: Other style pogo pins Cost: $0.90 Total Cost: $5.40 1 DB25 25-pin connector Part No: (Don t know, had some already) Alternate Part: Crimp style instead of solder style. Cost: $3.50 (Approx) 1 DB25 Shell (Optional) Part No: (Don t know, had some already) Cost: $3.50 (Approx) How to build Megavolt s Small Buffered JTAG v1.2 by DO999 Page 23

Qty Description Image 2 SPDT Switch (Optional) Part No: 35-001 Cost: $5.49 Each Total Cost: $10.98 1 20-pin Socket for 74HCT244 (Optional) Part No: DM-320STG30- CF Alternate Parts: Open frame low-profile Cost: $2.99 1 SIP Socket strip for resistor networks (Optional) Part No: SIP64S-TG30 Cost: $4.99 1 Project Box (Optional) Part No: K-JM12-IE-000 Alternate Parts: Any small project box Cost: $2.99 How to build Megavolt s Small Buffered JTAG v1.2 by DO999 Page 24

Qty Description Image 1 Circuit Board Part No: 276-148A (2 per package) Alternate Parts: Any small project board Cost: $3.49 (Approx) How to build Megavolt s Small Buffered JTAG v1.2 by DO999 Page 25