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I have two processors (STM and Infineon) on the same board and I have to organize communication between them. Yet I'm using Ethernet to communicate between them, but a startup time of Ethernet after turning on takes to much time (~2s). Could I setup communication over Ethernet without PHY drivers and so decrease the startup time?

If it's impossible, which interface can I use instead of it? The main requirements: fast startup time - 100 - 200 ms and communication speed not less than 10 Mb/s.

EDIT: I'm using STM32F407 and Infineon TriCore TC234

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    \$\begingroup\$ What options have you considered so far? \$\endgroup\$ – Andy aka Jun 29 '17 at 11:22
  • \$\begingroup\$ SPI, USB, there are many options to choose from. \$\endgroup\$ – Colin Jun 29 '17 at 11:25
  • \$\begingroup\$ Infineon doesn't have USB interface \$\endgroup\$ – Sauber Jun 29 '17 at 11:26
  • \$\begingroup\$ And what about Ethernet communication without PHY drivers? \$\endgroup\$ – Sauber Jun 29 '17 at 11:40
  • \$\begingroup\$ I've seen two DSPs communicate on on the same board via TCP/IP over a SPORT link. If both processors have compatible interfaces there is no need for the ethernet PHY. \$\endgroup\$ – Peter Karlsen Jun 29 '17 at 11:43
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At 10 Mbit/s, you can use SPI, maybe two separate busses, one for each direction. Or, you can roll your own interface with maybe 8 parallel data lines and a few handshaking lines.

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Manufacturers such as IDT and Cypress make dual-port RAM chips that make it easy for two processors to exchange messages with minimal software overhead. They also make FIFO chips — a pair of which would accomplish the same thing with fewer pins.

I work with FPGAs a lot; I would be tempted to use a small one to create a shared memory that has dual SPI interfaces.

I2S buses can also be used to stream data at such speeds. What about SDIO? Really, this would be a lot easier if you told us exactly which chips you're using, and which hardware resources are still available in your design.

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  • \$\begingroup\$ Infineon doesn't implement SDOI. I edited my question and told about processors. \$\endgroup\$ – Sauber Jun 29 '17 at 12:04
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    \$\begingroup\$ That's a start -- and I added links for you. But which resources are you not already using in your design? \$\endgroup\$ – Dave Tweed Jun 29 '17 at 12:07
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An Ethernet communication between two devices acting both as MACs without using PHYs in between is actually possible. I have seen it and used it.

But not all MAC devices support something like this. You have to clarify this with the specific processors that you have.

Otherwise SPI would be a good choice as an alternative interface.

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  • \$\begingroup\$ How I could understand, that the communication without PHY is possible? \$\endgroup\$ – Sauber Jun 29 '17 at 12:34
  • \$\begingroup\$ If it isn't explicitly stated and also no application note or sth similar exists, then I would ask the customer support of ST and Infineon! \$\endgroup\$ – nickagian Jun 29 '17 at 12:56
  • \$\begingroup\$ If your MACs support 1000BaseX (SGMII without autonegotiation), the MAC side and PHY side are symmetric and so you can directly connect two MACs. \$\endgroup\$ – DoxyLover Jun 29 '17 at 18:38

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