>/ But it seems to be very slow. I got a lot of packet errors, when loading a
binary... I will check my configuration files tomorrow and try to get a binary
loaded and debugged.
/yep - I discovered the same problem. It seems that it takes in the range of ms
(USB Poll interval?) between single commands. I got a TCK speed of about
100-300 Hz with LIBFTDI.
It becomes significantly faster if more than one byte is sent to libftdi in one
call. So there IMHO this calls for aggregation of data before passing it to the
interface.
Are there similar issues with comparable USB Devices?
Hi Felix,
They are two major troubles with the Altera USB Blaster :
1. This one could be corrected in the Openocd source :
I remember when Dominic (the creator / author of OpenOCD) ask me about
speed on december 2004 ... yes, 2004 !
I replied to Dominic to queue a maximum of commands before sending to
the Amontec JTAGkey ( http://www.amontec.com ).
This was what we done on begin of 2005 in the OpenOCD ft2232 API driver.
So if you want to accelerate the Altera USB Blaster you have to queue
the commands in the API driver and then send a sequence of command to
the device.
2. This one cannot be corrected/modified in the OpenOCD source ( Blaster
hardware issues):
A debug session of a ARM or ARM Cortex processor need to have control of
SRST (System Reset) and sometimes TRST (TAP Reset). The Altera USB
Blaster do not provide these signals by default and this will be a
potential source of error when connecting to your target.
Also, the RTCK (Return Clock) is not supported by the USB Blaster. The
RTCK is really important to have on ARM7tdmi-s or the newer Cortex-A9
(Ax) ... to name a few. The RTCK helps to synchronize the JTAG Emulator
with the target frequency.
The JTAG frequency of the Blaster is difficult to manage. It is OK for
programming a FPGA, but troubleshooting when debugging a ARM !
Regards,
Laurent Gauch
http://www.amontec.com
Amontec USB JTAG Cable JTAGkey Series
Amontec JTAGkey-2 hardware key features :
backward compatible with Amotnec JTAG key
SRST TRST RTCK signal support
JTAG frequency software programmable from 500Hz to 30Mhz
maximum 30MHz JTAG
JTAG IOs auto-sense from 1.3V to 5.5V
UHS buffers providing 32mA output on each JTAG IO s
Hi-speed USB 2.0 480MHz
SRST and TRST programmable as push-pull or open-drain
SRST can be monitored
VREF can be monitored
USB plug-and-play
JTAG hot-plug
four (4x) on-board LEDs
windows WHQL certified drivers (from wondows 2000 to windows win 7 32
bits and 64 bits)
Linux driver
MAC OSx driver
_______________________________________________
Openocd-development mailing list
Openocd-development@lists.berlios.de
https://lists.berlios.de/mailman/listinfo/openocd-development
