On 2010-12-03 14:31, Rolf Meeser wrote:
This patch allows a board script to specify the CPU clock of the LPC2478 target.
The clock frequency used to be fixed to 4 MHz. However, there is no default
frequency for this CPU. You mustn't assume prior knowledge of the clock
frequency, but rather demand that the user (board script) specifies it.
This clock frequency is the CPU clock at the time of flash programming! Usually
board scripts will enable the PLL to speed up debugging/programming. This MUST
be the correct frequency, or flash programming will fail or produce unreliable
results.
This will break all LPC2478 board or user scripts. Users must add the intended
operating clock frequency before they include the target script:
set CCLK 72000
source [find target/lpc2478.cfg]
Looks wrong to me.
First of all, the chip frequency after reset actually is 4MHz due to
internal RC oscillator, so this "default frequency" assumption seems
pretty correct (actually it was probably me who added that script to
OpenOCD).
Debugging is negligibly faster when using high clock, flash programming
duration gain is probably also negligible (what's the difference between
waiting for 20 seconds to waiting for 10 seconds?). Anyway - I never
enable PLL before flash programming, I bet that most "regular users"
also don't.
But most of all - this makes running OpenOCD with just command line
arguments impossible (openocd -f interface/sth.cfg -f
target/sth_else.cfg), as now you have to have your board config file.
Please - don't go this way.
4\/3!!
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