Kumar Gala wrote:
On Oct 10, 2008, at 2:29 AM, Wolfgang Grandegger wrote:
Kumar Gala wrote:
On Sep 30, 2008, at 3:55 AM, Wolfgang Grandegger wrote:
Measurements with our MPC8544 board showed that the I2C bus frequency is wrong by a factor of 1.5. Obviously, the interpretation of the MPC85xx_PORDEVSR2_SEC_CFG bit of the cfg_sec_freq register is not correct. There seems to be an error in the 8544 RM.
Signed-off-by: Wolfgang Grandegger wg@grandegger.com
cpu/mpc85xx/speed.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
can you do me a favor and dump the value of MPC85xx_PORDEVSR2. Also can you tell me what rev 8544 you have.
See below:
pordevsr2@e00e0014=0x8f00007d
CPU: 8544E, Version: 1.1, (0x803c0111) Core: E500, Version: 2.2, (0x80210022) Clock Configuration: CPU: 667 MHz, CCB: 334 MHz, DDR: 167 MHz (334 MT/s data rate), LBC: 41 MHz L1: D-cache 32 kB enabled I-cache 32 kB enabled Board: Socrates
Wolfgang.
thanks. How did you do the measurements that got you this 1.5x factor?
This afternoon I re-measured the I2C bus clock frequency with the oscilloscope at the I2C clock line on our Socrates MPC8544 board. With the patch applied, I measured the correct frequency of 100 kHz. Without, it was a factor of 1.5 too high.
Wolfgang.