Martin,
thanks for your hints.
Martin Krause schrieb:
Hi Andre,
[EMAIL PROTECTED] wrote on :
All,
in my current system the I2C bus is not working properly on a MPC8343
in
u-boot v1.3.2.
i2c board config includes :
#define CONFIG_HARD_I2C
#undef CONFIG_SOFT_I2C
#define CONFIG_FSL_I2C
#define CONFIG_I2C_MULTI_BUS
#define CONFIG_I2C_CMD_TREE
#define CFG_I2C_OFFSET 0x3000
#define CFG_I2C2_OFFSET 0x3100
#define CFG_I2C_SPEED 100000
#define CFG_I2C_SLAVE 0x7F
chip probing works fine.
mvBL-M7> i2c probe
Valid chip addresses: 30 48 50 68
reading the Chips gives all "ff"
mvBL-M7> i2c md 50 0 10
Uh, it seems I lag behind in U-Boot evolution. I know this
"i2c md" command as "imd"?
0000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
................
Devices with address 50 normally are EEPROMs. If this device is an
EEPROM, are you sure it contains data other than 0xff?
Yes - it's the configuration data of the CPU.
I can see the transaction on the bus - all data is correct. U-boot shows
0xff.
The number of address bytes a device needs is varying. Your could
look up the correct address length in the datasheet of your device,
or try it manually:
imd 50.0 0 10
imd 50.1 0 10
imd 50.2 0 10
One of this should work.
no - only 0xff.
Scope shows valid I2C transactions with correct data.
Observing the I2C bus wires show that everything _works excellent_ :
100kHz speed as well as all data seems ok - but u-boot shows "ff".
BTW: Fetching HRCW from I2C is also working fine.
After some tries (i2c md ..) the bus hangs and no more transactions
can
be seen on the bus.
One reason for a hanging bus could be a lost clock pulse. This could
happen, if the low->high rise time of the bus signal is longer than
the clock pulse width. For testing you could try a lower bus clock
(10 kHz for example).
rise time is ~200ns.
Best Regards,
Martin Krause
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