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Diffstat (limited to 'doc/README.MPC866')
| -rw-r--r-- | doc/README.MPC866 | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/doc/README.MPC866 b/doc/README.MPC866 new file mode 100644 index 000000000..1464a408c --- /dev/null +++ b/doc/README.MPC866 @@ -0,0 +1,19 @@ +The current implementation allows the user to specify the desired CPU +clock value, in MHz, via an environment variable "cpuclk". + +Three compile-time constants are used: + + CFG_866_OSCCLK - input quartz clock + CFG_866_CPUCLK_MIN - minimum allowed CPU clock + CFG_866_CPUCLK_MAX - maximum allowed CPU clock + CFG_866_CPUCLK_DEFAULT - default CPU clock value + +If the "cpuclk" environment variable value is within the CPUCLK_MIN / +CPUCLK_MAX limits, the specified value is used. Otherwise, the +default CPU clock value is set. + +Please note that for now the new clock-handling code has been enabled +for the TQM866M board only, even though it should be pretty much +common for other MPC859 / MPC866 based boards also. Our intention +here was to move in small steps and not to break the existing code +for other boards. |