COREMP7 Datasheet, PDF (25/30 Pages) Actel Corporation – CoreMP7

CoreMP7
The signals on the JTAG interface are shown in Table 7.
Table 7 • JTAG Signals
Signal
I/O
Description
DBGACK
–
This pin is connected in the RealView ICE run control unit, but is not supported in the current
release of the software. It is reserved for compatibility with other equipment to be used as a debug
acknowledge signal from the target system. It is recommended that this signal is pulled LOW on
the target.
DBGRQ
–
This pin is connected in the RealView ICE run control unit, but is not supported in the current
release of the software. It is reserved for compatibility with other equipment to be used as a debug
request signal to the target system. This signal is tied LOW. When applicable, RealView ICE uses the
core's scanchain 2 to put the core in debug state. It is recommended that this signal is pulled LOW
on the target.
GND
–
Ground
nSRST
Input/
Output
Open collector output from RealView ICE to the target system reset. This is also an input to
RealView ICE so that a reset initiated on the target can be reported to the debugger. This pin must
be pulled HIGH on the target to avoid unintentional resets when there is no connection.
nTRST
Output
Open collector output from RealView ICE to the Reset signal on the target JTAG port. This pin must
be pulled HIGH on the target to avoid unintentional resets when there is no connection.
RTCK
Input
Return Test Clock signal from the target JTAG port to RealView ICE. Some targets must synchronize
the JTAG inputs to internal clocks. To assist in meeting this requirement, you can use a returned,
and retimed, TCK to dynamically control the TCK rate. RealView ICE provides Adaptive Clock
Timing that waits for TCK changes to be echoed correctly before making further changes. Targets
that do not have to process TCK can simply ground this pin.
TCK
Output Test Clock signal from RealView ICE to the target JTAG port. It is recommended that this pin is
pulled LOW on the target.
TDI
Output Test Data In signal from RealView ICE to the target JTAG port. It is recommended that this pin is
pulled HIGH on the target.
TDO
Input
Test Data Out from the target JTAG port to RealView ICE. It is recommended that this pin is pulled
HIGH on the target.
TMS
Output Test Mode signal from RealView ICE to the target JTAG port. This pin must be pulled HIGH on the
target so that the effect of any spurious TCKs when there is no connection is benign.
Vsupply
Input
This pin is not connected in the RealView ICE run control unit. It is reserved for compatibility with
other equipment to be used as a power feed from the target system.
VTref
Input
This is the target reference voltage. It indicates that the target has power, and it must be at least
0.628 V. VTref is normally fed from Vdd on the target hardware and might have a series resistor
(though this is not recommended). There is a 10 k pull-down resistor on VTref in RealView ICE.
v2.6
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