eX Automotive Family FPGAs
Silicon Explorer II Probe
Silicon Explorer II is an integrated hardware and
software solution that, in conjunction with Actel
Designer software tools, allows users to examine any of
the internal nets of the device while it is operating in a
prototype or a production system. The user can probe
into an eX device via the PRA and PRB pins without
changing the placement and routing of the design and
without using any additional resources. Silicon
Explorer II's noninvasive method does not alter timing or
loading effects, thus shortening the debug cycle.
Silicon Explorer II does not require relayout or additional
MUXes to bring signals out to an external pin, which is
necessary when using programmable logic devices from
other suppliers.
Silicon Explorer II samples data at 100 MHz
(asynchronous) or 66 MHz (synchronous). Silicon
Explorer II attaches to a PC's standard COM port, turning
the PC into a fully functional 18-channel logic analyzer.
Silicon Explorer II allows designers to complete the
design verification process at their desks and reduces
verification time from several hours per cycle to a few
seconds.
The Silicon Explorer II tool uses the boundary scan ports
(TDI, TCK, TMS and TDO) to select the desired nets for
verification. The selected internal nets are assigned to the
PRA/PRB pins for observation.
illustrates the
interconnection between Silicon Explorer II and the
automotive-grade eX device to perform in-circuit
verification.
Design Considerations
The TDI, TCK, TDO, PRA, and PRB pins should not be used
as input or bidirectional ports. Since these pins are active
during probing, critical signals input through these pins
are not available while probing. In addition, the Security
Fuse should not be programmed because doing so
disables the probe circuitry. It is recommended to use a
70Ω series termination resistor on every probe connector
(TDI, TCK, TMS, TDO, PRA, PRB). The 70
Ω
series
termination is used to prevent data transmission
corruption during probing and reading back the
checksum.
Table 1-7 •
Device Configuration Options for Probe Capability (TRST pin reserved)
JTAG Mode
Dedicated
Flexible
Dedicated
Flexible
–
Notes:
1. If TRST pin is not reserved, the device behaves according to TRST = High in the table.
2. Avoid using the TDI, TCK, TDO, PRA, and PRB pins as input or bidirectional ports. Since these pins are active during probing, input
signals will not pass through these pins and may cause contention.
3. If no user signal is assigned to these pins, they will behave as unused I/Os in this mode. Unused pins are automatically tristated by
Actel’s Designer software.
TRST
1
Low
Low
High
High
–
Security Fuse Programmed
No
No
No
No
Yes
PRA, PRB
2
User I/O
3
User I/O
3
Probe Circuit Outputs
Probe Circuit Outputs
Probe Circuit Secured
TDI, TCK, TDO
2
Probing Unavailable
User I/O
3
Probe Circuit Inputs
Probe Circuit Inputs
Probe Circuit Secured
16 Pin
Connection
Serial
Connection Silicon Explorer II
TDI
TCK
TMS
TDO
PRA
PRB
22 Pin
Connection
Additional 16 Channels
(Logic Analyzer)
Figure 1-13 •
Silicon Explorer II Probe Setup
eX FPGAs
1 -1 0
v3.2
ACTEL [ Actel Corporation ]
