WIZnet W7500 ARM MCU with Ethernet PHY - do you use them ?  - Page 1
Forum section: electronics / general

author: Miyuki
author_rank: Frequent Contributor
timestamp: October 10, 2019, 06:38:13 pm
content: Hi folks ?Do you have experience with this wiznet Ethernet MCU ? Or some older ones ?I know their iEthernet W5100 series are nice solutions when need connectivity to existing MCUAnd this look line nice all in one chip with everything integratedI need some solution for bridge Ethernet to Si4432 and NRF24L01 controllers with some Web GUIThis look reasonably simple and cheap, better than using separate controller and W5100

author: ejeffrey
author_rank: Super Contributor
timestamp: October 11, 2019, 03:09:33 am
content: I've used the w5500 with a separate ARM cortex m0+ micro. I have to say it is fairly easy to use and works but I am not thrilled with the whole concept. It's basically a security nightmare since you don't have the resources to implement encrypting or authentication, and in the restricted environment of a small micro very hard to avoid using fixed size buffers and hard to protect against buffer overflows and the like. So in most cases it isn't really something you should be attaching to anything but a completely isolated and access controlled network. At that point why bother with Ethernet rather than just a simpler USB serial interface?Like I said, I have used it and there are legitimate applications, but the potential for misuse, or for a device to be later moved to an inappropriate environment is really high.There are a number of IoT development libraries that try to support security in low end devices, but I don't know if they support the wiznet chips or if you would have to add it that yourself. I checked OpenThread and did not see device support for any wiznet chips.

author: fchk
author_rank: Frequent Contributor
timestamp: October 11, 2019, 11:13:12 am
content: I'd rather use this:http://www.ti.com/product/TM4C129ENCZADhttp://www.ti.com/tool/EK-TM4C129EXLYou geht a nice RTOS with TCP/IP Stack, and the chip has hardware crypto.fchk

author: Miyuki
author_rank: Frequent Contributor
timestamp: October 11, 2019, 11:29:01 am
content: I want use it for thinks like home automation/controlIt look like a really price competitive device, it cost less than STM32F107 alone and no need for external PHY and additional costTo connecting it to raw internet it must be discussed with some security experts, but what I know about most software stacks there are lot of problems, and speed is sometimes problem, and full OS solution is also not easy way as we all know

author: nctnico
author_rank: Super Contributor
timestamp: October 11, 2019, 06:32:16 pm
content: Quote from: ejeffrey on October 11, 2019, 03:09:33 amI disagree. Fixed buffer means: don't accept more data than what fits in the buffer (discard the rest). From a security point of view the W5500 is a good solution because you get a very clean seperation between your business logic and internet stuff. And you can do good encryption and authentification in a microcontroller but it is not going to be TLS/SSL (which is too bloated for this purpose anyway). And since the encryption and authentification is in the microcontroller it doesn't matter whether the W5500 gets compromised or not.I have used the W5500 for an IoT design and IMHO it is a very good fit from both the ease of use and security point of view. I have been down the road of having an internal TCP/IP stack (uip) but this wasn't a very good experience. The TCP/IP stack turned out to be very buggy and not very secure.

author: Jeroen3
author_rank: Super Contributor
timestamp: October 11, 2019, 06:48:01 pm
content: Remember anything not doing TLS/SSL should only listen to class A,B or C ip's.Those are 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16.Drop all others.Go with a solution like fchk suggested. Or find some other part.However, I would suggest that for embedded networking you just add a small linux board. This is so much easier to get running, keep stable and up to date.

author: nctnico
author_rank: Super Contributor
timestamp: October 11, 2019, 06:59:37 pm
content: Quote from: Jeroen3 on October 11, 2019, 06:48:01 pmThis is utter nonsense. What TLS/SSL is doing (in the end) is creating an encrypted tunnel over which you communicate. You only need the encryption algorithms and some key management to do that. The whole TLS/SSL stack is way overkill to achieve this goal AND it has much more attack vectors compared to an approach which doesn't have so much functionality. TLS/SSL has a long history of vulnerabilities! Adding Linux to the mix just makes matters worse with even more possible attack vectors.

author: voltsandjolts
author_rank: Unknown
timestamp: October 11, 2019, 07:04:54 pm
content: Cross-refhttps://www.eevblog.com/forum/microcontrollers/anyone-used-the-wiznet-ethernet-chips/

author: ttt
author_rank: Regular Contributor
timestamp: October 11, 2019, 08:01:50 pm
content: I got their eval board from DigiKey (WIZWIKI-W7500P). It's only then that I realized how bad the documentation and toolchain is. If you search around you'll find horror stories about the bugginess of the hardware in general.Cost wise a combo of STM32F107RB + LAN8720A is very similar. You'll get a vastly better MCU (Cortex-M3), better documentation, better tool chain and lots of resources online for help. You need a few more passives with this solution but one big advantage is that you can use the STM32 MCO pin to drive the 50Mhz clock of the PHY chip. For the W7500P you need two separate crystal oscillators (8Mhz + 25Mhz) which will impact total BOM.

author: Miyuki
author_rank: Frequent Contributor
timestamp: October 12, 2019, 01:02:15 pm
content: Quote from: ttt on October 11, 2019, 08:01:50 pmYes I was little nervous about their documentation and toolchain.I might use SAME5 instead of STM32 (but it is not big difference)