BCM1250/BCM1125/BCM1125H
User Manual
10/21/02
B r o a d c o m C o r p o r a t i o n
Page
424
Section 15: JTAG and Debug
Document
1250_1125-UM100CB-R
BYPASS Instruction
The required BYPASS instruction allows the processor to remain in a functional mode and selects the Bypass
register to be connected between TDI and TDO. The BYPASS instruction allows serial data to be transferred
through the processor from TDI to TDO without affecting its operation. The bit code of this instruction is defined
to be all ones by the IEEE 1149.1 standard. All unused instructions default to the BYPASS instruction.
IDCODE Instruction
The IDCODE instruction selects the Device Identification (ID) register to be connected between TDI and TDO.
The Device ID register is a 32 bit shift register containing the 11 bit manufacture id (11’h150), the 16 bit part-
number (this matches the part number in the
system_revision
register) and the 4 bit version number. The
idcode register is scanned out LSB first and is shown in
The version number is 4’h1 for prototype BCM1250, 4’h2-4’h8 or 4’hb for initial production BCM1250 and 4’h9
for later production BCM1250 (stepping C0). The version number is 4’h1 for initial production BCM1125/H.
WAFERID Instruction
The WAFERID instruction selects the WaferId register to be connected between TDI and TDO. The WaferId
register is a 32 bit shift register containing a manufacturing lot code number. The register is scanned out LSB
0x33
reserved
0x34
SCANMC
Broadcom Use Only. Selects MC Chain.
0x35
reserved
0x36
SCANSCD
Broadcom Use Only. Selects SCD Scan Chain.
0x37
reserved
0x38
SCANALL
Broadcom Use Only. Selects All Agent Scan Chains in Series.
0x39
reserved
0x3A
BSRMODE
Keep boundary scan register active even if other JTAG commands used.
0x3B
TRACECURCNT
Selects the current trace event counts for scan out.
0x3C
CLAMP
Selects the BSR onto the outputs and selects the bypass register between TDO and TDI.
0x3D
SAMPLE/
PRELOAD
Selects the boundary scan register. Cause a snapshot to be taken of the state of the pins
on the rising edge of TCLK next time the state machine is in the Capture-DR state. This
is as required by the JTAG standard.
0x3E
INTEST
Sets up boundary scan for intest mode. This selects all of the inputs of the chip for control
by JTAG.
0x3F
BYPASS
Bypass Mode. Select the bypass register between TDI and TDO, as required by the JTAG
standard.
Table 299: JTAG Instructions
(Cont.)
IR Value
Instruction
Function
Table 300: JTAG Device ID Register
3
1
3
0
2
9
2
8
2
7
2
6
2
5
2
4
2
3
2
2
2
1
2
0
1
9
1
8
1
7
1
6
1
5
1
4
1
3
1
2
1
1
1
0
9
8
7
6
5
4
3
2
1
0
Jtag
Version
Number
JTAG part number
JTAG Manufacturer
1
v
v
v
v
p
p
p
p
p
p
p
p
p
p
p
p
p
p
p
p
0
0
1
0
1
0
1
0
0
0
0
1