TAP, Boundary Scan, and OCE
MSC8144E Reference Manual, Rev. 3
Freescale Semiconductor
25-7
0xF1
CLAMP
Yes
Optional in the IEEE Std. 1149.1. This public instruction selects the one-bit
Bypass Register as the serial path between TDI and TDO, while allowing
signals driven from the component to be determined from the Boundary
Scan Register. During testing of ICs on PCBs, it may be necessary to place
static guarding values on signals that control logic operations not involved in
the test. The EXTEST instruction can be used for this purpose, but since it
selects the BSR, the required guarding signals would be loaded as part of
the complete serial data stream shifted in, both at the start of the test and
each time a new test pattern is entered. Since the CLAMP instruction allows
guarding values to be applied using the BSR of the appropriate ICs while
selecting their Bypass Registers, it allows much faster testing than
EXTEST. Data in the boundary scan cell remains unchanged until a new
instruction is shifted in.
Note:
The CLAMP instruction also asserts internal reset for the
MSC8144E system logic to force a predictable internal state while
external boundary scan operations are performed.
0xF2
HIGHZ
Yes
Optional in the IEEE Std. 1149.1. It is a manufacturer’s public instruction to
prevent back-drive of the outputs during circuit-board testing. When HIGHZ
is invoked, all output drivers, including the two-state drivers, are turned off
(that is, high impedance). The HIGHZ instruction selects the Bypass
Register. It also asserts internal reset for the MSC8144E system logic to
force a predictable internal state while external boundary scan operations
are performed.
0xF3
IDCODE
Yes
Selects the ID Register. This instruction is a public instruction to allow the
manufacturer, part number and version of a component to be determined
through the TAP. The ID Register configuration is as follows:
• Bits 31–28: Version Information
• Bits 27–12: Customer Part Number
• Bits 11–1: Manufacturer Identity
One application of the ID Register is to distinguish the manufacturer(s) of
components on a board when multiple sourcing is used. included in the
design.
As required by the IEEE Std. 1149.1, the operation of the test logic has no
effect on the operation of the internal system logic when the IDCODE
instruction is selected. The value for the MSC8144E is 0x0188801D.
0xFE
STATUS
Yes
Private instruction that allows the user to scan out STATUS from the
Instruction Register without changing the Instruction Update Register.
0xFF
BYPASS
Yes
Selects the single-bit Bypass Register. This creates a shift-register path
from TDI to the Bypass Register and, finally, to TDO, circumventing the
573-bit BSR register. This instruction enhances test efficiency when a
component other than the MSC8144E-based device is the device under
test. When the current instruction selects the Bypass Register, the
shift-register stage is set to a logic zero on the rising edge of TCK in the
CAPTURE
-
DR
controller state. Therefore, the first bit to be shifted out after the
Bypass Register is selected is always a logic zero.
Clocking Control
0x05
FREEZE
Yes
Private instruction that stops the clocks. The instructions causes all device
clocks to stop. Resuming execution from this stopped state is not possible.
Table 25-3. Instruction Decoding (Continued)
Opcode
Instruction
Updates IR
Description
Summary of Contents for MSC8144E
Page 1: ...MSC8144E Reference Manual Quad Core Media Signal Processor MSC8144ERM Rev 3 July 2009 ...
Page 48: ...MSC8144E Reference Manual Rev 3 xlviii Freescale Semiconductor ...
Page 86: ...MSC8144E Reference Manual Rev 3 1 38 Freescale Semiconductor Overview ...
Page 168: ...MSC8144E Reference Manual Rev 3 3 60 Freescale Semiconductor External Signals ...
Page 242: ...MSC8144E Reference Manual Rev 3 5 26 Freescale Semiconductor Reset ...
Page 314: ...MSC8144E Reference Manual Rev 3 8 24 Freescale Semiconductor General Configuration Registers ...
Page 414: ...MSC8144E Reference Manual Rev 3 10 14 Freescale Semiconductor MSC8144E SC3400 DSP Subsystem ...
Page 452: ...MSC8144E Reference Manual Rev 3 11 38 Freescale Semiconductor Internal Memory Subsystem ...
Page 520: ...MSC8144E Reference Manual Rev 3 12 68 Freescale Semiconductor DDR SDRAM Memory Controller ...
Page 1070: ...MSC8144E Reference Manual Rev 3 21 28 Freescale Semiconductor Timers ...