presto_en.pdf - 第90页

Page 90 • The RUNTEST comma nd contain ing run_co unt and specifying min_time is execut ed at the current ly running TCK frequenc y. Th erefore t he command can take much more time t han what is specified in min_time. • …

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The maximum frequency is 3MHz for the PRESTO
programmer and 15MHz for FORTE.
If the Ignore FREQUENCY commands option is selected,
the programmer applies only the frequency set by the
user and ignores all FREQUENCY commands.
8.2.2 Fast Clocks Option
(FORTE only)
This option is available only for the FORTE programmer.
According to the JTAG specification, the signal at TDI is
sampled at TCK's rising edge. However, should a higher
frequency be required (around 5MHz or more), it may be
useful to change the moment of sampling from the rising
edge to the falling edge by shifting it by 1/2 of the TCK
period. To do so, choose Fast Clock Option.
8.2.3 RUNTEST without
run_count (SVF only)
The programmer should stay in the specified state for the
specified time and generate the clock signal on TCK while
executing an SVF file.
The specified time can be exceeded, but it slows the
programming process down. Even though it is not
supported by the SVF specification, many programmable
devices allow stopping the TCK clock during this time.
The programmer's ability to keep accurate time needs to
be considered. A high level of accuracy cannot be
achieved if the maximum frequency is used (the
programmer can guarantee respecting the min_time SEC
parameter only). A higher accuracy can be achieved with
slow clock (~100kHz). If the clock signal is not used at
all, the programmer is capable of following the min_time
SEC parameter almost exactly.
Three possibilities are available considering these facts:
• no clock on TCK
• slow clock on TCK (~100kHz)
• default speed clock on TCK
Example: "RUNTEST 3E-3SEC;" means "Generate clock on
TCK for at least 3ms".
8.2.4 RUNTEST Timing
Multiply (both SVF
and XSVF)
Recommended values:
• for accurate timing specified in the SVF or XSVF file:
0% (no added time)
• for XC9500(XL) family: 100% or more
• for Atmel AVR (e.g. ATmega128): 25%
8.2.5 RUNTEST with
run_count and no
timing
(bothSVFandXSVF)
This command should be interpreted as the minimum
frequency on TCK.
Yet some SVF file generators (such as Xilinx iMPACT, for
example) use this command as waiting time and assume
a frequency of 1MHz. For such cases the use of "interpret
as RUNTEST min_time with scale 1MHz" setting is
recommended.
JTAG Player Behavior When Reaching RUNTIME
Command With MINTIME Specification
(This concerns only SVF files as the RUNTEST alternative,
which is usable in XSVF XRUNTEST run_count cannot
specify time.)
Page 90
• The RUNTEST command containing run_count and
specifying min_time is executed at the currently
running TCK frequency. Therefore the command can
take much more time than what is specified in
min_time.
• The RUNTEST command containing run_count and
specifying max_time is executed at the currently
running TCK frequency. As the programmer cannot
respect the “deadline” specified in the max_time
parameter, this parameter is ignored.
8.2.6 VPP PRESTO / P
FORTE pin usage
while running test
(file) / after test
completion
The selection of the VPP / P pin function: TRST or SCK as
described in the SVF file or user-defined output levels.
(This is useful to keep the device in the reset state during
file execution.)
8.2.7 Default Settings
The JTAG Player features several default settings intended
primarily for use in connection with FORTE, but not with
PRESTO. Feel free to change these settings if the default
values do not suit your application.
Default Settings for FPGAs
Default TCK frequency: 15MHz; Ignore FREQUENCY
commands
Fast Clock Option (FORTE only): 5MHz and above
RUNTEST without run_count (SVF only): default
speed clock on TCK
RUNTEST timing multiply (both SVF and XSVF): 0%
RUNTEST with run_count and no timing (both SVF
and XSVF): interpret as RUNTEST min_time with scale
1MHz
VPP PRESTO / P FORTE pin usage while running test
(file): Tristate
VPP PRESTO / P FORTE pin usage after test
completion: Tristate
Default Settings for XC9500
Default TCK frequency: 5MHz; Ignore FREQUENCY
commands
Fast Clock Option (FORTE only): 5MHz and above
RUNTEST without run_count (SVF only): slow clock
on TCK (~100kHz)
RUNTEST timing multiply (both SVF and XSVF):
100%
RUNTEST with run_count and no timing (both SVF
and XSVF): interpret as RUNTEST min_time with scale
1MHz
VPP PRESTO / P FORTE pin usage while running test
(file): Tristate
VPP PRESTO / P FORTE pin usage after test
completion: Tristate
Default Settings for AVR:
Default TCK frequency: 1MHz; Ignore FREQUENCY
commands
Fast Clock Option (FORTE only): 5MHz and above
RUNTEST without run_count (SVF only): default
speed clock on TCK
Page 91
RUNTEST timing multiply (both SVF and XSVF):
25%
RUNTEST with run_count and no timing (both SVF
and XSVF): interpret as RUNTEST min_time with scale
1MHz
VPP PRESTO / P FORTE pin usage while running test
(file): Tristate
VPP PRESTO / P FORTE pin usage after test
completion: Tristate
8.3
Running JTAG Player
from Command Line
SVF & XSVF JTAG Player can be run from the command
line for more comfort especially during debugging. The
following parameters apply:
jtagplay.exe [-p] [-f filename] [-i inifile] [-
c] [-cc] [-s serial]
-p automatically executes the file specified in
the -f filename parameter
-f filename specifies SVF / XSVF file to be executed
-i inifile ini file containing settings
-c closes the program if the file has been
executed without errors
-cc closes the program even if the file has been
executed with error(s)
-s serial uses PRESTO or FORTE programmer of the
specified serial number, when instead of
the serial number there is the "-" (dash)
sign, it will use any connected programmer
regardless of its serial number
-forte uses FORTE, not PRESTO
Return Codes
The jtagplay.exe program returns the following return
codes:
0 execution of the last file had no errors
1 an error occurred during execution of the
last file
2 execution of the last file could not be
started