What could be the problem if I'm not able to write this value to this register?
*AT91C_EMAC_TCR = 0x30;
If I take a look in the memory window I don't see this value in this register...
assembly-window shows this code for this c-line:
0x100002E4 E3A00030 MOV R0,#0x00000030 0x100002E8 E2441911 SUB R1,R4,#0x00044000 0x100002EC E5810010 STR R0,[R1,#0x0010]
Looks really good, but it doesn't work... I'm working with the AT91Rm9200 controller from Atmel.
best regards Johannes
"If I take a look in the memory window I don't see this value in this register"
You didn't say what you do see. Anyway, I wouldn't expect to see 0x30. The CSR bit is write-only.
"Looks really good, but it doesn't work"
What about it doesn't work. Are you basing "doesn't work" on the inability to read back 0x30 as described above?
the register AT91C_EMAC_TCR can be read and write - and I write my data lenght for the trasmit paket in this register.
I work with wireshark to look for the data paket I transmit - and it has 0 Bytes - it's empty. That's my problem. The pointer to the data which should be transmitted is correct (I can see the address of this pointer in the register for the ethernet).
"the register AT91C_EMAC_TCR "
My apologies. I see where I went wrong by pulling up the data sheet PDF and clicking the "Control Register" section, not "Transmit Control Register". The "Control Register" has the write-only CSR bit I referred to.
Sorry again for taking your issue on a side trip.
Is the minimum Ethernet frame size 64 bytes?
Yes, the minimum TCP/IP frame size is 14 bytes header and 46 bytes data, which - with a 4-byte CRC will be 64 bytes.
I got the error - it was a false pointer which overwrites a few values, so everything was 0...
Johannes