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xcore / sc_ethernet

10/100 MII Ethernet MAC for XMOS microcontrollers
http://xcore.github.com/sc_ethernet/index.html
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What does NUM_MII_RX_BUF/NUM_MII_TX_BUF do & why is it important? #23

Closed interactive-matter closed 12 years ago

interactive-matter commented 12 years ago

I have solved the mysteries of my issue #20:

I had to set

define NUM_MII_RX_BUF 5

define NUM_MII_TX_BUF 5

but I had set it to

define NUM_MII_RX_BUF 20

define NUM_MII_TX_BUF 2

(which I copied from some other ethernet_conf.h)

It took me 2! complete days to discover this. It would be extremely great to have some kind of warning like 'running out of tx buffers' or so. Because from anything in the source I was not able to tell what the problem was.

And what does 5 mean? 5 frames? 5 bytes?

I am a bit puzzled …

interactive-matter commented 12 years ago

sorry, there was something else wrong/right does not work anymore - giving really up

DavidNorman commented 12 years ago

I don't have the code here but by the name I'm guessing it is the client queue size.

The memory management has undergone several revisions and so the count of the buffers is no longer as relevant as it used to be.

I'll give you more details on Monday.

David Norman Bristol

On 15 Dec 2011, at 17:45, "Interactive Matter" reply@reply.github.com wrote:

I have solved the mysteries of my issue #20:

I had to set

define NUM_MII_RX_BUF 5

define NUM_MII_TX_BUF 5

but I had set it to

define NUM_MII_RX_BUF 20

define NUM_MII_TX_BUF 2

(which I copied from some other ethernet_conf.h)

It took me 2! complete days to discover this. It would be extremely great to have some kind of warning like 'running out of tx buffers' or so. Because from anything in the source I was not able to tell what the problem was.

And what does 5 mean? 5 frames? 5 bytes?

I am a bit puzzled …

Reply to this email directly or view it on GitHub: https://github.com/xcore/sc_ethernet/issues/23

ajwlucas commented 12 years ago

This is the number of TX/RX packets buffered in the MAC. It's possible that TX packets were being dropped because the size was only 2. There are dropped packet counters that you can enable to detect this but they aren't printed by default because they would reduce performance.