The process of programming the internal flash memory uses the IR path of the JTAG state machine to select or address specific registers in the flash controller and then uses the DR path to read or write the selected register.

The programming algorithm for a MSP430 does have one extra complication.  It uses the TDI pin to perform two different functions depending on which state the TAP controller state machine is in.

In all but the Run Test Idle state the TDI pin performs its normal function, allowing 1s and 0s to be shifted into the DR and IR registers, but in the Run Test Idle state the TDI input  becomes the TCLK input.  The TCLK input is used to clock the internal flash controller, causing data to be written to memory, and should not be confused with the standard TCK input used to clock the JTAG state machine.

The TCLK input has another restriction in that it has to be clocked at 350 kHz.  This can be achieved by setting the JTAG system’s TCK frequency to 700 kHz. Any pin on the XJLink can only be changed once per TCK period so this results in a 350 kHz TCLK signal.

If you are interested in using the MSP430 code we have developed, please, contact support@xjtag.com for more information.

(These tips assume the JTAG chain is already configured)

1. Start from the bottom of the Unassigned Devices list, i.e. with the series resistors, and work your way up.
2. As components are categorised and more are discovered go back to the bottom and work your way up again.
3. Once you have classified the first batch of series resistors it is worth checking any new Suggested Series Resistors that appear immediately.  It is unusual to have multiple series resistors on the same net.  If you get lots of new series resistors for classification is it likely that a power net has not been correctly categorised.
4. Classify all Suggested Resistor Packs as pull resistor packs and then use the errors to identify which ones should really be classified as series resistor packs.
5. In general capacitors go in the ignore list.  The only time they do not is if they happen to be on a net between two 1149.6 devices.
6. Unused connectors and headers go in the ignore list.
7. When classifying a Suggested Device use the Explorer to check there is enough access to a device to test it before spending the time locating the right XJEase script.
8. Test points go in the Unfitted category.  This stops them having an effect on the DFT coverage report.  Uncheck “Only Show Accessible Devices” to make sure they are all found.
9. Classify any fuses, ferrite bead, or inductors with a PDD file so that all the power nets on the board are correctly identified.  Again, uncheck “Only Show Accessible Devices” to make sure they are all found.
10. Make sure you read any BSDL file warnings (before you disable warnings on those devices). Reading them is likely to explain why the JTAG chain didn’t run the first time you tried it…

The good news is that the OMAP processors do support boundary scan testing. The bad news is that it does not work straight out of the tin.

TI do provide the instructions that are required to enable the boundary scan registers:

http://e2e.ti.com/cfs-file.ashx/__key/CommunityServer.Components.PostAttachments/00.00.10.29.73/OMAP343_5F00_BSDL.pdf

http://processors.wiki.ti.com/index.php/Boundary_Scan_on_OMAP35x

Unfortunately these do not give the whole story and the boundary scan register still will not function correctly:

http://e2e.ti.com/support/dsp/omap_applications_processors/f/447/p/35977/130644.aspx

If you need to do boundary scan testing with a OMAP 35xx contact XJTAG Support (support@xjtag.com) and we will complete the story for you.

Our new telephone numbers are:

Support/Sales: +44 (0)1223 223007
Fax:           +44 (0)1223 223009

 
and our new postal address is

XJTAG
St John's Innovation Centre
Cowley Road
Cambridge
CB4 0WS.

When you first test a new circuit board that doesn’t work this diagnostics test can give you confidence that your XJlink2 hardware is working correctly. The test takes a few minutes to run but tests all of the internal features of the XJlink2 in detail. The test includes checks on:

• all of the connector signal driver transistors
• all of the signal input buffers
• the connector power supplies
• the internal signal communication buses
• the internal clock sources
• and the integrity of the internal program.
• the push-button
• and the LEDs.

You can optionally use a loop-back connector ( pin1 to pin11, pin2 to pin 12 etc) to provide enhanced testing of the connector itself.

If you think you might have damaged your XJlink2 then just run the self test. If a test fails please copy the entire report along with your serial number to support@xjtag.com so that we can help you.

The diagnostics feature is an excellent way to confirm that the XJLink2 is working correctly.

If you need to let us know about a problem that you are having with XJTAG there are a few things that you can do help speed up the support process.

There are a few stock responses that we have to give repeatedly to many support requests. If you are reading this then you may well have received them in the past yourself. The first thing that we will generally ask you to do is upgrade to the latest version of the tools; these can be downloaded from XJTAG Downloads. You will need your maintenance user name and password to gain access to this section of the website. If you are not sure of these details then email support@xjtag.com and we will be glad to send you a reminder email.

If you are using the latest version of the tools then we will need as much information as you can provide to help us to resolve your problem. This includes:

• The version of the tools you are using
• The version of the operating system (e.g. Windows XP Service Pack 3)
• A detailed description of the problem or issue you are facing
• Is it reproducible? If so, what steps are needed to reproduce it?

In many cases it helps us to diagnose your problems faster if we have your XJTAG project as well as your description of the problem you are having. The best way to send us all of the files is to use the Export option from the File menu in XJDeveloper. From this menu you can tell the system to create a .ZIP archive of all of the files that make up your project.  By using XJDeveloper to pull all of these files together you make sure that no files are missed.

If we have all the information early on in the support process along with your project, we are much more likely to be able to resolve the issue quickly.

If the tool you are using is crashing then it will create a crash report and then give you the opportunity to send that to us. Please do send this report to us as it contains a lot of useful information. We may still need to ask you for more information; however if you go through these steps before contacting us then we should be able to help you resolve your issue faster.

Knowledge Base

Answers to common questions we receive about XJTAG. Before contacting support it is a good idea to check here first to see if your question is answered. There will be future posts exploring some of these questions in more detail.

XJEase Example Code

Some types of device such as memory devices can be tested using standard test scripts. This section contains test code for a wide variety of memory and other devices.

XJEase Library

If you cannot find the device you are looking for in the Example Code folder, the XJEase Library might contain it. This has a search facility to help you find the test script for the part. It is quite likely that XJTAG have already produced a file for that device – or at the very least a similar device. Search here first and if you cannot find it then contact support.

Updates

Allows you to download the latest version of XJTAG.

JTAG

Excellent overview of the background to JTAG testing, along with details about its implementation.

DFT Guidelines

When designing boards refer to this document to help improve the testability of circuits using XJTAG.

Application Notes

Further areas of technical knowledge that are worth reading before contacting support.