DP83869HM: DP83869HM polarity and IEEE802.3x support

Hello Kai, 

Q1: Yes, reverse polarity is fine as it will be automatically detected. The results will be shown in register 0x11. Bits 2-5 on that register correspond to what is reversed and what is not. According to Table 36, for those bits, a ‘1’ in bit 5 would correspond to channel D being in reverse polarity. A ‘0’ in bit 4 would correspond to normal polarity for channel C. And so on.

Q2: Yes. For this configuration, bits 5-2 on register 0x11 would be “1011”.

Q3: The MAC would write to that register on the PHY as being capable or not, and the PHY would then advertise that capability to the link partner.

Q4: Could you be more specific as to what issue you are running into?

Sincerely,

Gerome

Hi Gerome,

Regarding Question 4, customer just wants to know whether you have any experience of 10base-Te support trouble between DP83869HM and AM5726 or not so experience base answer is ok like "no 10base-Te trouble experience" or "yes, we had xxxx and how to address".

Regarding Question 3, could I ask more detail?
my question for #3 is, in other words, does IEEE802.3 cover IEEE802.3x?

If IEEE802.3 covers IEEE802.3x, DP83869HM supports IEEE802.3 so no problem.

Question 3
DP83869HM supports IEEE802.3.
If phy supports IEEE802.3, is it ok to say that phy also supports IEEE802.3x(flow control) or additioanl comment is needed like "phy supports IEEE802.3 and IEEE802.3x"?
Q3: The MAC would write to that register on the PHY as being capable or not, and the PHY would then advertise that capability to the link partner.

regards,
Kai

Hi Kai,

In regards to Question 3, an additional comment would need to be made regarding a PHY supporting IEEE802.3x.

In regards to Question 4, no, we have not experienced any 10BASE-Te issues between the DP83869HM and AM5726.

Thanks,

Gerome

Hi Gerome,

thanks, I understand it means DP83869HM doesn't support IEEE802.3x.
Next question is do we have any GbE supporting IEEE802.3x?

Regards,
Kai

Hi Gerome,

I asked about this again to customer and I summarized it as below figure.

when we send 300KByte data from PC to Product, 1 packet is 1500byte so total 200 cycle(300K/1500) is needed.
if Processor A 1 window support 4 packets, total window is 300K/(1500byte*4packets)=50 windows.

Customer question here is whether DP83869HM loses the packet or not when the data is "10BASE-T".

background of this quesiton is they have experience that a certain phy loses the packet when the phy receieve initial packet or taking longer duration between packet to packet.
the reason of that packet loss is a certain phy stops the RX_CLK during no data so phy loses the packet when phy try to re-establish the RX_CLK.

They are worry that DP83869HM has the same problem  with 10BASE-T or not.

Regards,
Kai

Kai,

RX_CLK is a continuous clock output whose frequency depends on the link established with its link partner. We do not expect it to stop, and so the packets should not be lost.

Thanks,

Gerome