Is it possible to interface an ENC28J60 to 16F877A mcu ??

[arunb]

Hi,

Compiler:PCM
MCU:16F877A

Is it possible to use an ENC28J60 with a 16F877A or 16F648A mcu ?? or do I need an mcu with a larger RAM ??

Also can I implement a webserver using the ENC28J60 ??

thanks
arunb

[PCM programmer]

asmallri could answer this one, or you could ask it on the Microchip
Ethernet forum:
http://forum.microchip.com/tt.aspx?forumid=173

[asmallri]

[arunb]

Hi,

Thank you for the reply.

Actually I just want to interface my applications with a LAN network, just for this application do you think a 16F877A will do the job ??

I have been reading some datasheets of ENC based interface products (example: LJCV electronics; nic28) and there it is mentioned that any mcu could be used, no restriction on RAM or program memory was stated...

thanks
arunb

[asmallri]

[arunb]

Hi,

Do I need to implement a stack for even an ethernet interface ?

I won't be needing the web server...

thanks
arunb

[asmallri]

[Douglas Kennedy]

No you don't need a stack to run ethernet. All ethernet packets have a preamble that the hardware provides a header with the destination and sender MAC address ( botth six bytes each) and a two byte type field ( a.k.a SAP or service access point) followed by your payload data that you provide. There is a minimum size in bytes and a maximum size for your payload data (46-1500) at the end there is a 4 byte CRC
The internet protocols (IP) are merely added features and protocols wrapped inside the basic ethernet layer identified with a 0x800 type value. You could even use the type field as the length field for your payload but it's better to pick your own type code and use the first few bytes of your payload to indicate it's length

[arunb]

Hi,

I would like to use the ENC connected to a PIC (this PIC contains all the implementations for ethernet access).

These two devices will become a module that can be used to interface with my controller modules or cards. The interfacing between the module and the controller is done serially.

When the controller needs to send data, it sends the data to the ethernet module serially, the ethernet module PIC uses the appropriate protocols to send data over the LAN network.

The same process is used to receive data.

In this context do you think the 16F877A has the necessary resources ??

thanks
arunb

The

[Douglas Kennedy]

Both the CCS stack and the Microchip stack implementations involve simplifications on the full protocols. Ex TCPIP calls for packets to be resent that aren't received correctly and received out of sequence packets are to be resquenced. With a PIC then implementing this would require additional RAM both to store outgoing packets until a confirmation is received and to store incoming packets until a true sequence is there( this is RAM in addition to the ring buffer the ENC provides) So the simplified Microchip and CCS code assumes true receipt and true sequencing. With the resources you have available you need to pick what will fit. You must have the MAC layer so first start there. What you need to add depends on what you know about your LAN setup. The IP protocols provide ways to discover an unknown MAC address. Resolve web names to IP addresses handle overspeeding of the receiving device by window control provide additional information of the status of the connection provide for sockets etc. At some point you have to pick and choose since not all the code will fit into the 16F877A. If you can't build up the code layer by layer yourself them you are much better served by using an 18Fxxx with the maximum of program space and the most RAM ( Ex 18F8720) and use the CCS stack.

[asmallri]