Problem to write TJA1100 registers

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Problem to write TJA1100 registers

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e_lionel
Contributor I

Hello,

I use a TJA1100 (PHY BroadR Reach) and I communicate beetwen MCU MPC5748G and TJA1100 with the SMI link : signals MDIO and MDC.

I can read all the internal registers inside the TJA1100 without any problem => I read the right value for PHY_ID, TYPE_NO, PHYAD[4:0], ...

But I can't write these registers - which can be in R/W - and I can't change the "CONFIG_EN" bit in the Extented Control register (17), too.

The 2 signals MDIO and MDC (2.5 MHz) seems OK on scope for Read (0x10) and Write (0x01) operations.

After reading the TJA1100 registers, the TJA1100 is in the following configuration:

Basic Control Register (0) = 0x2100  => POWER_DOWN = 0(Normal Operation) , ISOLATE = 0 (normal operation)

PHY identification register 1 (2) = 0x0180

PHY identification register 2 (3) = 0xDC41

PHY identification register 3 (16) = 0x00A9

LINK_CONTROL = 0 (disable)

POWER_MODE = 1100 (Standby Mode)

CONFIG_EN = 0 

CONFIG_INH = 1

AUTO_PWD = 0

MASTER_SLAVE = 0 or 1 (depending of my hardware configuration)

AUTO_OP = 0 (managed operation)

PHY_STATE = 000 (Idle).

Why it's not possible to write inside TJA1100 registers and not possible to change the "CONFIG_EN" bit (register 17) ?

Thanks for your futurs answers (or questions).

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guoliangzhang
Contributor I

hi, now that i have encountered a similar issue, i wonder if you have found a solution to the problem? 

i was able to write to the config_en though, but not able to change anything on the basic control register. 

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