An Overview of JTAG

1
An Overview of JTAG

• CPSC 462
• Computer Science Department
• Texas AM University

Note Most of the technical material and artwork
are Taken from vendor published datasheets and
publicly posted web pages
2
Open Ground, Vdd
Between chips, boards, wafer - bond wires
(Source TI 1997 JTAG premier)
3
Source TI 1997 JTAG premier)
4
JTAG architecturehardware
Source TI 1997 JTAG premier)
5
Data/test bit multiplexing
Source TI 1997 JTAG premier)
6
Bit stream control flow
Source TI 1997 JTAG premier)
7
Boundary Scan Description Language (BSDL)
elements (1-4)
Source TI 1997 JTAG premier)
8
BSDL(2-4)
Source TI 1997 JTAG premier)
9
BSDL(3-4)
Source TI 1997 JTAG premier)
10
BSDL (4-4)
Source TI 1997 JTAG premier)
11
BSDL examples

• PMC sierra 3386 example
• Altera EP1K30F256 (256 pins)
• http//www.xjtag.com/sup-bsdl.htm

12
Some vendors

• Intellitech
• http//www.xjtag.com/index.htm
• http//www.corelis.com