read access issue about sja1105qel

[SungBong]

Hi. 

Our system uses SJA1105QEL ethernet switch (Host is MPC5748G).

I want to read configuration value. so i tried to access address 0x00000000 (ETH_DYN 0x00h) but the result of read access is same as write access (SDO is mirrored as SDI).

According to the software manual, i understand that first 32 bits are access control value and next 32 bits are ignored value for reading data.

So, i tested following method in S32 project.

 -test code

-result 

Do you think this method is wrong or other problem exists?

please any help for me.

best regards.

thank you.

[guoweisun]

Suggest to write this register firstly then read it to verify the content.

[SungBong]

Dear guoweisun.

i already wrote static configuration data such as below before read access.

do i need anything else?

best regards.

[guoweisun]

You can read your written content now?

[SungBong]

where write access, the data is transmitted via SDO. 

i can read buffer after write access.

buffer has mirroring data from SDO same as SDI.

[guoweisun · Accepted solution]

Refer to this timing format!

[guoweisun]

Yes,please follow the timing !

[SungBong]

I solved this issue.

i think it was SS signal problem.

i should have checked Continous SS option in S32DS.

thank you for your help a lot.

best regards.

[SungBong]

you mean i need to insert delay time between first 32 bits and second 32 bits for t3?

[guoweisun]

Data (containing the number of 32-bit quadlets to be read and address to read from) is
received on the SDI input of the switch and is treated as a sequence of 32-bit quadlets.
Data corresponding to the address received is output on SDO pin of the switch.

[SungBong]

Dear guoweisun.

thank you for your reply.

In my case, i want to read a register value at 0x00. 

Where read access, i understand first 32 bits are mirrored same data via SDO.

I expect to read next not mirrored 32 bits data via SDO. but the next 32 bits are also mirrored SDI data. 

i think it is something wrong.

is my test code wrong or not?

best regards.