1. JTAG Emulators JTAG emulator Target System Debugger software
Parallel port
And a little bit of
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JTAG Emulators

2. Introduction We know what JTAG is – don’t we?
Testing loaded boards is becoming prohibitively expensive and more difficult to perform due to increasing complexity of circuit boards.
JTAG method of testing reduces the cost and difficulty of board-level testing.
The standard provides a cost-effective method of board testing through use of the boundary scan technique.
Boundary Scan
With CASCON 4.12 SW
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JTAG Emulators

3. That can’t be all it can do!
We’ll see what else it’s good for…
TRY - You’ll find the word EMULATOR in most of your results.
Emulator??? Let’s look in
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JTAG Emulators

4. EMULATOR – what’s that? Mis-named Device Mis-named Device
EMULATOR – A device built to work like another.
But like what? What are we trying to emulate?
Mis-named Device
Mis-named Device
the JTAG only defines an interface between the embedded system and the PC. The part who is actually performing the emulation is the chip, acting like a PC.
Mis-Named
Ronaldo de Assis Moreira
a.k.a
Ronaldo Gaucho
HUH?
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JTAG Emulators

5. Hardware Emulator - a window to the embedded system
Hardware debugging utilities allow the processor control and data to be passed from the embedded system to a PC where debugging can occur
Hardware debugging allows setting breakpoints in code, stepping, executing blocks of code, inspection of all the control registers and data structures, feed data onto chip
Emulates the Cpu:
System sees real processor fitted
Programmer has full control of the system
BreakPoint for Serbia:
6:0 from Argentina
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JTAG Emulators

6. ICE – In-circuit Emulator
A specially-instrumented microprocessor - the “original” processor or microcontroller of the target hardware will be replaced by the ICE.
Allows to stop execution, examine CPU state, modify registers
The CPU allows as much debugging functionality as a debugger within a monitor program, but does not take up any memory
Main drawback to ICE is that the machine is specific to a particular microprocessor, even down to the pinout
This is actually ICE
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JTAG Emulators

7. In-Circuit Emulator – cont.
In-circuit emulator (ICE) is the best (most powerful)
but:
Very difficult to integrate (mount the emulator on the target board); Custom variants of processors may not be supported by ICE at all
Heisenberg Effects of In-Circuit Emulation - The act of observing the processor changes its operation
Lack of ‘Post Mortem’ Debug features
Problems With Hardware Breakpoints while Cache and MMU are enabled
Typically very expensive - 25k or more
Very expensive:
Andrey Shevchenko bought by Chelsea:
£30.8m
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JTAG Emulators

8. Debugging tools – JTAG
A JTAG Emulator is a tool that uses the on-chip debug features of a microprocessor to provide debug services.
Emulation Solutions as low as 2.8k 
Support for full speed operation for all accesses
On-Chip Breakpoint Logic which allows breakpoints to work even when the CACHE and MMU translation are enabled
Hot Plug - Let's you plug into a target after a crash and see what happened
Auto ID - Detects the processor you are connected to and also the FLASH type
Perform Target Operations - Even While Running
Running
the fastest?
Gianluca Zambrotta
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JTAG Emulators

9. JTAG Emulator – How does it work?
JTAG Emulators are real-time, transparent in-circuit emulators based on the JTAG boundary scan port.
Debug of the hardware is performed by stopping the core to enable information to be scanned into and out of the device via the JTAG header.
This information is transferred serially through the JTAG port following IEEE JTAG specifications.
To communicate with the emulator,the target system must have a 14-pin header (two rows of seven pins)
the scan chains used for emulation purposes are different from those used for boundary scan.
Internally to the processor, there are various serial scan chains in which the information can be scanned into and out of. The control of which scan chain is used and what information is contained in each scan chain, is performed by a microprocessor.
This “scan manager” has the task of controlling this information as it is scanned to and from the various processors in the scan chain, and directing it to and from the various debugger windows.
JTAG target devices support emulation through a dedicated emulation port.
This port is a superset of the IEEE standard and is accessed by the emulator. To communicate with the emulator, your target system must have a 14-pin header (two rows of seven pins)
TMS Test mode select O I
TDI Test data input O I
TDO Test data output I O
TCK Test clock. TCK is a MHz clock source from the emulation cable pod. This signal can be used to drive the system test clock O I
TRST‡ Test reset O I
EMU0 Emulation pin 0 I I/O
EMU1 Emulation pin 1 I I/O
PD(VCC) Presence detect. Indicates that the emulation cable is connected and that the target is
powered up. PD should be tied to VCC in the target system. I O
TCK_RET Test clock return. Test clock input to the emulator. May be a buffered or unbuffered version of TCK. I O
GND Ground
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JTAG Emulators

10. JTAG Emulator – How does it work?
The JTAG connection is the same way we know and love
but:
Various scan chains inside the processor
Microprocessor controls what scan chain is used and what information is contained.
This “scan manager” has the task of controlling this information as it is scanned to and from the various processors in the scan chain, and directing it to and from the various debugger windows.
the scan chains used for emulation purposes are different from those used for boundary scan.
Internally to the processor, there are various serial scan chains in which the information can be scanned into and out of. The control of which scan chain is used and what information is contained in each scan chain, is performed by a microprocessor.
This “scan manager” has the task of controlling this information as it is scanned to and from the various processors in the scan chain, and directing it to and from the various debugger windows.
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JTAG Emulators

11. JTAG Emulator – How is it used?
DSP (Digital Signal Processor) - specialized microprocessor designed specifically for digital signal processing, generally in RT.
Found at the heart of cell phones, audio and video players, digital cameras, telephony infrastructure, motor control systems, and even biometric security equipment.
DSPs offer many architectural features that actually reduce the number of instructions necessary for efficient signal processing. The programmable flexibility of DSPs enables developers to implement complex algorithms in software.
Digital signals can be sent over longer distances than analog signals without data loss
Filtering and cleaning up analog signals requires closely-matched and expensive components where digital filtering is implemented in flexible code
Working with signals in the digital domain simplifies enhanced signal processing, including effects, adjusting resolution or bit rate, and moving between formats to increase device interoperability
Perfect copies of digital signals, such as audio or video content, are possible, making every copy as good as the master, compared to analog copies which degrade with each generation of copy
Improving signal quality or channel density is a matter of increasing the performance of the DSP
DSPs are programmable, enabling developers to continually improve quality without redesigning hardware
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JTAG Emulators

12. JTAG for DSP
JTAG is used solely for fast data transfer purposes. Usually data is sent and received through the conventional parallel ports.
However, JTAG allows high-speed data transfer and connects to the JTAG pins on your board. For TI DSP's, some based JTAG emulators specifically allow High Speed RTDX and other features.
For applications on Real-Time Video and Image Processing, JTAG will be very crucial. However, the down side is that JTAG is fairly expensive. In fact, in most cases it is more expensive than the DSP board itself.
The first consideration when choosing an emulator, is does it support the required DSP family?
~500$
~3,000$
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JTAG Emulators

13. JTAG Emulator – How does it work?
JTAG emulators are available with PCI, USB 2.0, LAN, and PCMCIA JTAG controllers, to allow flexibility in designing the host - target environment.
Vary in:
code download speed
portability (obviously)
size of application is also a factor
price to pay
Some Emulators have an onboard processor that handles up to 75% of all JTAG Processing. Others use the PC processor.
For portable applications using a notebook a PCMCIA, Parallel Port or USB based emulator is the best solution. For Desktop debugging solutions - ISA and PCI cards are also an option and for remote debugging there are emulators which can be used over a LAN.
For portable, laptop or notebook based, applications it is normally not possible to use an
ISA or PCI based emulator. For such applications a PCMCIA, Parallel Port or USB
based emulator is the best solution. For a dedicated notebook solution then a PCMCIA
emulator is perhaps the best solution as it is hot plugable, easy to configure and much
faster than the other two options. The new USB based emulators are also hot plugable
and easy to configure but tend to be rather slow on many targets. Parallel Port
emulators are a low-cost flexible solution but users have experienced problems as some
laptops do not fully implement the parallel port specification with the result that the
emulator is unable to establish bi-directional communication with the PC.
Parallel port and USB based emulators are very flexible because they are also suitable
for use with desktop PC systems, but here ISA and PCI cards are also an option. As the
ISA standard is rapidly becoming obsolete then for a fast, future proof, internal board
based emulator the best solution is to choose one of the new PCI based boards. For
users who want the ability to debug a remote target then there are dedicated Ethernet
emulators available as well as software which will allow a PCI emulator to be used over
a LAN.
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JTAG Emulators

14. JTAG Emulators
Parallel Port emulators are a flexible low cost devices. The parallel port connection allows the emulator to be used with both desktop and laptop computers.
USB based emulators offer a flexible solution for both desktop and laptop PCs. A USB emulator is compact, easily installed, hot-plugable and needs no external power supply. Speed – USB 2.0!
PCI emulator - a high performance internal emulator. The main advantage - the fast communication speed between the host computer and the DSP target. Result - faster code download times and better DSP/BIOS and RTDX performance.
A PCMCIA emulator - laptop or notebook PC users. Faster than the Parallel Port and USB based alternatives. Hot-plugable; gives PCI type performance on a portable platform.
For portable, laptop or notebook based, applications it is normally not possible to use an
ISA or PCI based emulator. For such applications a PCMCIA, Parallel Port or USB
based emulator is the best solution. For a dedicated notebook solution then a PCMCIA
emulator is perhaps the best solution as it is hot plugable, easy to configure and much
faster than the other two options. The new USB based emulators are also hot plugable
and easy to configure but tend to be rather slow on many targets. Parallel Port
emulators are a low-cost flexible solution but users have experienced problems as some
laptops do not fully implement the parallel port specification with the result that the
emulator is unable to establish bi-directional communication with the PC.
Parallel port and USB based emulators are very flexible because they are also suitable
for use with desktop PC systems, but here ISA and PCI cards are also an option. As the
ISA standard is rapidly becoming obsolete then for a fast, future proof, internal board
based emulator the best solution is to choose one of the new PCI based boards. For
users who want the ability to debug a remote target then there are dedicated Ethernet
emulators available as well as software which will allow a PCI emulator to be used over
a LAN.
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JTAG Emulators

15. DSP Development tools – Host side
Host Development Tools for DSP Development IDE - integrated development environment.
A typical DSP IDE consists of several major components:
Code generation (compile, assemble, link)
Edit
Simulation
Real-time analysis
Debug and emulation
Graphical user interface
Efficient connection to a target system
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JTAG Emulators

16. TI - Code Composer Studio IDE
The Code Composer Studio (CCS) application provides an integrated environment with the following capabilities:
Integrated development environment with an editor, debugger, project manager, profiler, etc.
‘C/C++’ compiler, assembly optimiser and linker (code generation tools).
Simulator.
Real-time operating system (DSP/BIOS™).
Real-Time Data Exchange (RTDX™) between the Host and Target.
Real-time analysis and data visualisation.
Debugging a TI DSP
using
3.1 CCS
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JTAG Emulators

17. The End
Out In
Parallel Port emulators are a flexible low cost devices. The parallel port connection allows the emulator to be used with both desktop and laptop computers.
With USB ports now commonplace on all PC platforms, USB based emulators offer a flexible emulation solution suitable for both desktop and laptop PCs. A USB emulator is compact, easily installed, hot-plugable and needs no external power supply. Newer USB2.0 ports also offer significant speed increases on previous USB1.1 based emulators.
PCI emulator is suitable for users wanting a high performance internal emulator. The main advantage of a PCI based emulator is the fast communication speed between the host computer and the DSP target. This can result in faster code download times and better DSP/BIOS and RTDX performance.
A PCMCIA emulator - for users working on a laptop or notebook PC. Faster than the Parallel Port and USB based alternatives a hot-plugable PCMCIA emulator gives PCI type performance on a portable platform.
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JTAG Emulators