2022-11-07 11:20 AM
I'm developing my first STM ethernet application and want to use it's built in MAC, from my understanding any 10/100 ETH PHY with MII or RMII should work but there's such a big list of those on market, ST Disco boards I found use LAN8740, which is expensive and somewhat hard to obtain, some tutorials I saw used LAN8720, KSZ8xxx.
My main concern is if there is a big difference I'm missing out or will any of these products work same? Any experienced dev input would be appreciated on which of these IC-s is more recommended over the others.
#Edit: I was planning on using F107 for it but now memory has become a concern, if anyone has a general idea of how much memory ethernet libraries usually take up, I'd love to know it.
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2022-11-08 05:11 PM
Your understanding ir correct. While a feature set differs, almost any part with MII/RMII interface will work. Regarding the software, for the basic functionality the only thing that differs is a register address and positions of two bits, which indicate the speed and duplex mode selected by auto-negotiation.
DP83848 is pretty old. Nothing wrong with it, but never designs are typically better and/or cheaper. Most of ST's non-expensive boards use LAN8742A, which is a nice part. But at this point I would recommend the DP83825I - pretty advanced, small, cheap, a new design and available.
From STM32, if possible, I would avoid F1 and use at least F2 series.
Regarding memory usage read my post in this topic:
2022-11-07 10:03 PM
Right now the biggest problem seems availability.
I think most Nucleo-boards are using the LAN8742A, I do so too on a board still in development (but doing good so far on the HW side).
I see no reason for using MII instead of RMII, as you're havin HF stuff on your PCB anyway, but maybe there's something I don't know.
2022-11-07 11:35 PM
About memory, you can evaluate. But you can check DP83848.
2022-11-08 01:44 AM
It does really seem like most of the phys I checked, including the two you guys suggested are out of stock or overpriced on most retailers, Does it boil down to whatever PHY I can get my hands on? The code part should be basically same for all of them right? (except the initialization)
2022-11-08 03:25 AM
Do you have none other requirements to the PHY? Just the plain vanilla 10/100 RMII?
Then get whatever is available and ask the vendor how to connect it to STM32.
2022-11-08 05:11 PM
Your understanding ir correct. While a feature set differs, almost any part with MII/RMII interface will work. Regarding the software, for the basic functionality the only thing that differs is a register address and positions of two bits, which indicate the speed and duplex mode selected by auto-negotiation.
DP83848 is pretty old. Nothing wrong with it, but never designs are typically better and/or cheaper. Most of ST's non-expensive boards use LAN8742A, which is a nice part. But at this point I would recommend the DP83825I - pretty advanced, small, cheap, a new design and available.
From STM32, if possible, I would avoid F1 and use at least F2 series.
Regarding memory usage read my post in this topic:
2022-11-09 09:33 AM
Thanks for you response, that was very informative!
2022-12-27 07:32 AM
Do you maybe have an example driver using the DP83825I?