It is obviously some configuration issue, but I cannot figure out what is the problem.
I start the socket as a TCP server and I can connect from client normally. But when I try to send one char from server to client, client receives some garbage stream.
I have set:
tx mem size (0x001B) as 0x55 (2kb per socket)
tx write pointer 0x0424 = 0x40
0x0425 = 0x00
when sending a char i first read the txWritePtr, one example is:
0x0424 => 0xD8
0x0425 => 0x90
Then i mask the pointer with 0x7ff and add to base addess 0x4000, which gives me address of 0x4090 on which I sent one character.
And after I update txWritePtr with new address
0x0424 = 0x40
0x0425 = 0x91
And of course send the Send command to command register. After that I receive quite amount of garbage (I dont really know how much characters I receive)…
I am sure it is some obvious mistake I am making, but longer I read the datasheet and look at the code, less I have ideas what could be the issue…
If you use the Socket0(allow the 2kb : tx size of socket0), socket0 have tx mem size as 0x4000~ 0x47FF.
And when socket connection is complete, S0_TX_WR value has random value in 0x4000~0x47FF.
It transmits data from current S0_TX_RR to S0_TX_WR and automatically changes after transmission is finished(After send command is completed and S0_IR(SEND_OK) is enable).
And if total TCP packet is less then 60byte, W5100 send 60byte packet including garbage data(padding data).
Yeah, I am not talking about padding data. This is like dumping of full buffer before posting the data I have sent.
Yes, I get random value of TX_WR and TX_RR is 0. Which means that every time it will send 0->TX_WR + my data ?
For example, TX_WR = 1000; my data is 24 bytes long, first time I initiate send it will send 1024 bytes, every other send is OK, it will just send 24 bytes.
Do I need to set the RR before writing to tx buffer ?
[quote=“gossamer”]0x0424 = 0x40
0x0425 = 0x91[/quote]
If you use all 16 bits updating the pointer, will that work for you? Thus pointer before you issue SEND command, when sending one char, will be:
0x0424 = 0xD8
0x0425 = 0x91
It sounds logical that you get long stream of garbage. In your case size of calculated data 4091-d890=6801 (26 625 bytes).
That was exactly the issue. Writing value on 0x4090, but setting txWritePtr to 0xD891 after writing one character. To be honest datasheet was so vague on this detail, that i would never figure it out
