TAP Expander for Blackhawk Emulators

The TAP Expander pod is an add-on accessory that enhances the functionality of a Blackhawk JTAG emulator to support daisy chaining up to four scan chains and allows the emulator to connect to a unit under test (UUT) with multiple TAP connectors. The TAP Expander internally routes the JTAG signals to the appropriate TAP connector. This allows signal integrity to be maintained when chaining TAPs and boundary-scan test coverage to be increased by allowing the interconnections between the different TAPs to be tested. The TAP Expander is operated under host software control and is compatible with the Corelis ScanExpress boundary-scan and functional test tools and all the various Blackhawk JTAG emulators.

By coupling the power of the ScanExpress boundary-scan tools with that of an emulator, a complete and integrated solution is now available that offers the best advantages of both boundary-scan and functional test methodologies.

Boundary-scan (JTAG) operates as the complementary companion to functional testing. Boundary-scan is the preferred solution for testing areas of printed circuit board assemblies that are difficult to access due to physical space constraints and lack of physical access, which is often due to fine pitch components such as Ball Grid Array (BGA) devices. The functional tests are executed at the processor speed and may be able to detect board level faults that boundary-scan won't find, such as a cold solder joint between a processor and a memory pin that boundary-scan will not. Additionally, the functional tests may check non-boundary-scan compatible portions of the unit under test (UUT) such as UARTs, ADCs, DACs, and I2C peripherals.

What is IEEE Standard 1149.1?

The TAP Expander facilitates software-controlled boundary-scan operations per IEEE Standard 1149.1. It provides command access to the target’s Test Access Port (TAP), accessing device internal registers and on-chip debugger, verifying PCB interconnects, performing functional testing, and debug without manual probing. The JTAG interface also provides access to internal device functions that are not accessible via external probing, enabling fault isolation within the device itself. The JTAG interface also enables programming target Flash and CPLD devices, as well as data download and uploading to and from the target memory devices.

The TAP Expander is often used to perform microprocessor emulation via the device JTAG port. It is used for firmware development providing single-step, break, and content update/visibility access.

Minimal Test Access Port

Minimal Test Access Port

TAP Expander Features

Adjustable Voltage Levels

The software-programmable voltage level of the TAP interfaces can be set to any voltage between 1.25V and 3.30V in increments of about 0.05V. The TI TAP and TAPs 1-3 use the same adjustable TAP voltage setting.

When set to “Automatic”, the TAP Expander sets the TAP voltage to match the voltage sensed on TVD (pin 5) of the TI DSP TAP connector.

Discrete Input/Output Signals

The TAP Expander operates three discrete input/output signals per TAP (1, 2, 3) under software control. These attach to the target TAP connector. They are driven or sensed as directed by software, in coordination with the scanning operation. Each such signal can be configured independently as TTL output or as input at the programmable voltage level. As outputs, these discretes are useful for providing control functions on the user target system such as general reset, power control, direct_write# pulse, disable/enable and/or similar signals for non-boundary-scan target stimulus.

Conversely, as inputs, they enable host sensing of the target to pace scanning activity or related conditions (such as a Flash ready/busy# signal).

Connecting to the Blackhawk Emulator

The Corelis TAP Expander module connects to the Blackhawk emulator through its captive ribbon cable.

The TAP Expander directly supports the Blackhawk controllers with a compact 20-pin JTAG connector. If the Blackhawk controller has a 14-pin JTAG connector, an adapter board (Corelis p/n 12111) that converts the 14-pin connector on the emulator to a compatible 20-pin connector will need to be used. If the Blackhawk controller has a 60-pin JTAG connector, an adapter board that converts the 60-pin connector on the emulator to a compatible 20-pin connector will need to be used.

Supported Blackhawk JTAG Emulators

XDS560 Trace System

XDS560 Trace System [NOTE 1]

XDS560-class Models

USB560BP JTAG Emulator [NOTE 2]
LAN560 JTAG Emulator
PCI560 JTAG Emulator
USB560 JTAG Emulator

XDS510-class Models

USB510 JTAG Emulator [NOTE 2]
PCI510 JTAG Emulator [NOTE 2]
USB510L Controller [NOTE 2]
USB2000 Controller [NOTE 2]

NOTE 1: Requires 60-pin high-density XDS560 Trace Module header to 20-pin Compact TI (cTI) target header adapter

NOTE 2: Requires 14-pin JTAG connector to 20-pin Compact TI (cTI) target header adapter (Corelis part number 12111)

Block diagram showing the use of the Corelis TAP Expander
with a Blackhawk TI DSP Emulator in a multi-TAP environment

For information on the Corelis Tap Expander, please click here to speak with a Sales Engineer.

TAP Expander Module (Top View)

About Blackhawk


	Blackhawk™ was the first to introduce a USB JTAG Emulator for Texas Instruments DSP’s and is a member of the Texas Instruments Third Party Developers Network.

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