Hello,
I have added your WIZ812MJ Ethernet module to my existing PIC24HJ based design, to create a TCP Ethernet facility.
I gave encountered a problem with reading certain registers.
One example is in the attached photos.
I am writing 0xAA to address 0x0420 (IMG_0009) and when I read back from 0x0420 I get x08 (IMG_0010).
I can do a successful write/read cycle to many registers, but not all.
This is causing me a major problem e.g. I cannot read S0_TX_WR for buffer control.
Please help, I cannot see what I am doing wrong.
Best Regards Mike.
Hi,
You maybe have mistaken.
Sn_TX_WR register address is 0x0424, not 0x420.
The register located at 0x0420, Sn_TX_FRS is read only register. If you read 0x08 from 0x0420, its value Sn_TX_FSR’s MSB value, maybe used in 2K TX buffer size (0x0800).
Please check the address of regsiter again.
Thanks.
hey, Wiggum23.
i can know your problem.
WIZ812MJ Used WIZnet’s W5100 chip.
on the datasheet of W5100, address 0420-0421 can’t write.
the register must use reading.
you says “I can do a successful write/read cycle to many registers, but not all.”,
i think it is you can’t check W5100’s datasheet or register’s character.
i hope this reply is helpful to you.
Many thanks for your replies,
I made a simple mistake.
I still couldn’t write/read to 0x0424 ( S0_TX_WR ) then I found this on another forum :-
“Looks like the Sn_TX_WR only gets updated AFTER a successful SEND! You’ll have to keep track of all the writes to the TX buffer and write the TOTAL bytes to send in the Sn_TX_WR register, perform the Send and then Sn_TX_WR can be read and will have the updated value in it.”
I am now getting good results but I think this should be added to the datasheet as soon as possible.
Best Regards Mike.
Hi,
In W5100 datasheet v1.2.4, It is already mentioned.
Thanks for your advice.
