SAA7146AH NXP Semiconductors, SAA7146AH Datasheet - Page 126

• Manufacturer Part Number: SAA7146AH
• Manufacturer: NXP Semiconductors

Specifications of SAA7146AH

• Lead Free Status / Rohs Status: Compliant

Philips Semiconductors
Table 116 BST instructions supported by the SAA7146A
8.1
The Test Access Port (TAP) controller of an IC should be
in the reset state (TEST_LOGIC_RESET) when the IC is
in functional mode. This reset state also forces the
instruction register into a functional instruction such as
IDCODE or BYPASS.
To solve the power-up reset, the standard specifies that
the TAP controller will be forced asynchronously to the
TEST_LOGIC_RESET state by setting the TRST_N pin
LOW.
8.2
A device identification register is specified in “IEEE Std.
1149.1 - Standard Test Access Port and Boundary-Scan
Architecture” . It is a 32-bit register which contains fields for
the specification of the IC manufacturer, the IC part
2004 Aug 25
handbook, full pagewidth
INSTRUCTION
Multimedia bridge, high performance
Scaler and PCI circuit (SPCI)
SAMPLE
BYPASS
EXTEST
IDCODE
CLAMP
Initialization of boundary scan circuit
Device identification codes
this mandatory instruction provides a minimum length serial path (1-bit) between TDI and TDO
when no test operation of the component is required
this mandatory instruction allows testing of off-chip circuitry and board level interconnections
This mandatory instruction can be used to take a sample of the inputs during normal operation of
the component. It can also be used to preload data values into the latched outputs of the boundary
scan register
This optional instruction is useful for testing when not all ICs have BST. This instruction addresses
the bypass register while the boundary scan register is in external test mode
this optional instruction will provide information on the components manufacturer, part number and
version number
TDI
MSB
31
version
4 bits
0000
code
28
Fig.45 32 bits of identification code.
27
0111000101000110
16 bit part number
126
12
DESCRIPTION
number and the IC version number. Its biggest advantage
is the possibility to check for the correct ICs mounted after
production and determination of the version number of ICs
during field service.
When the IDCODE instruction is loaded into the BST
instruction register, the identification register will be
connected between TDI and TDO of the IC. The
identification register will load a component specific code
during the CAPTURE_DATA_REGISTER state of the TAP
controller and this code can subsequently be shifted out.
At board level this code can be used to verify component
manufacturer, type and version number. The device
identification register contains 32 bits, numbered from
31 to 0, where bit 31 is the most significant bit (nearest to
TDI) and bit 0 is the least significant bit (nearest to TDO);
see Fig.45.
11
11 bit manufacturer
00000010101
indentification
1
MBH751
LSB
0
1
TDO
Product specification
SAA7146A