On the XA-SK-E100 schematic there are 10K pullup resistors on MODE0, MODE1, MDIO and MDC on the LAN8710 Phy. According to the data sheet for this part, these pullups should not be necessary.
Is there a reason they are there?
Ethernet Slice Kit Hardware Questions
https://www2.smsc.com/mkt/web_lancheck. ... enDocument
In general MDIO always requires a pull-up between 1.5K and 10K.When using the MII or the RMII interfac
e of the LAN8710I QFN with a MAC device on
board, a pull-up resistor on the MDIO signal
(pin 16) is required. A pull-up resistor of
1.5K to VDDIO is required for this application.
If they are pull-ups in the XMOS reference, I guess they are there to assure it has the right signal level.The Mode pins of the LAN8710I (MODE[2:
0]) control the default configuration of the
10/100 phy. Speed, Duplex, Auto-Negotiation & power down functionality can be
configured through these pins. The value of these three pins are latched in upon power-
up and reset. The values latched in are reflected in Register 0 & Register 4 of the
LAN8710I. See the LAN8710I data sheet for co
mplete details for the operation of these
pins. These three pins have weak internal pu
ll-ups and can be left as no-connects. To set
any Mode bit low, an external 10K pull-down resistor should be used.
Thanks for your response.
In the datasheet for the part, it says the MDIO has an internal pullup but in the checklist document you referenced, it says it needs an external one.
I guess I can take it up with Microchip if I want to save a resistor ;>)
In the datasheet for the part, it says the MDIO has an internal pullup but in the checklist document you referenced, it says it needs an external one.
I guess I can take it up with Microchip if I want to save a resistor ;>)