PM8621 PMC-Sierra, Inc., PM8621 Datasheet - Page 127

• Manufacturer Part Number: PM8621
• Description: NSE-8G Standard Product Data Sheet Preliminary
• Manufacturer: PMC-Sierra, Inc.

Proprietary and Confidential to PMC-Sierra, Inc., and for its Customers’ Internal Use
Document ID: PMC-2010850, Issue 1
Register 800H: NSE-8G Master Test
This register is used to enable NSE-8G test features. All bits, except PMCTST, and PMCATST
are reset to zero by a reset of the NSE-8G using the RSTB input. PMCTST is reset when CSB is
high; PMCATST is reset when CSB is high and RSTB is low. PMCTST and PMCATST can also
be reset by writing a logic 0 to the corresponding register bit.
Access to this register is not affected by the Test Mode Address Force functions in registers
1001H and 1002H.
HIZIO, HIZDATA
IOTST
DBCTRL
Bit
Bit 31:6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
The HIZIO and HIZDATA bits control the tri-state modes of the NSE-8G . While the HIZIO
bit is a logic one, all output pins of the NSE-8G except the data bus and output TDO are held
tri-state. The microprocessor interface is still active. While the HIZDATA bit is a logic one,
the data bus is also held in a high-impedance state which inhibits microprocessor read cycles.
The HIZDATA bit is overridden by the DBCTRL bit.
The IOTST bit is used to allow normal microprocessor access to the test registers and control
the test mode in each TSB block in the NSE-8G for board level testing. When IOTST is a
logic one, all blocks are held in test mode and the microprocessor may write to a block’s test
mode 0 registers to manipulate the outputs of the block and consequently the device outputs
(refer to the “Test Mode 0 Details” in the “Test Features” section).
The DBCTRL bit is used to pass control of the data bus drivers to the CSB pin. When the
DBCTRL bit is set to logic one and PMCTST is set to logic one, the CSB pin controls the
output enable for the data bus. While the DBCTRL bit is set, holding the CSB pin low causes
the NSE-8G to drive the data bus and holding the CSB pin high tri-states the data bus. The
DBCTRL bit overrides the HIZDATA bit. The DBCTRL bit is used to measure the drive
capability of the data bus driver pads.
Type
R
W
W
W
R/W
W
R/W
PMCATST
PMCTST
DBCTRL
HIZDATA
HIZIO
Function
Unused
IOTST
Default
X
X
X
0
0
0
0
NSE-8G™ Standard Product Data Sheet
Preliminary
126