On Jan 6, 2009, at 10:59 PM, Peter LaDow wrote:
1. How does one determine the proper CPUTAPID value for the "-expected_id"? Is this a trial and error thing?
Basically. The data sheet for the part _might_ say in the section on debugging. In general, we just get the value reported by an actual device.
2. Why does the LPC2148 configuration file default CPUTAPID to 0xffffffff, when other targets have specific CPUTAPID values (i.e. at91, zy1000, etc)? Can the LPC2148 have a different expected id?
The config files use 0xffffffff for devices that we support for but have not obtained the ID as reported by an actual device.
2. Do people have to reduce their JTAG speeds, even for the Olimex boards? I copied mine from the Olimex schematic, and there weren't any terminators, etc. Should there be some series terminations to help?
I'm not familiar with the electrical requirements for a JTAG interface. What I do know from watching this discussion and others: - The FT2232 can only go up to 6MHz due to the speed of the oscillator required
- Some of the supported interfaces can go faster than 6MHz- Some targets can only accept the JTAG chain running at a integer division of the target's system clock - RCLK is intended to allow the target to limit the JTAG speed to the fastest the target can go
- The FT2232 does not support RCLKSince you've determined that 1.5MHz works for your interface and board, run with it. The general rule for performance is that you stop tuning when it is faster than the user needs. If all of your debugging and flashing finish in a reasonable amount of time, just stick with it. Otherwise, you can do a binary search of JTAG speeds to determine what the maximum speed is for your interface/cable/board combination.
Thanks, Pete -- -- "To love for the sake of being loved is human; to love for the sake of loving is Angelic." -- Alphonse de Lamartine _______________________________________________ Openocd-development mailing list [email protected] https://lists.berlios.de/mailman/listinfo/openocd-development
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