JAJSC32E September 2012 – June 2019 DP83848-EP
PRODUCTION DATA.
The DP83848-EP supports a Preamble Suppression mode as indicated by a one in bit 6 of the Basic Mode Status Register (BMSR, address 01h.) If the station management entity (i.e. MAC or other management controller) determines that all PHYs in the system support Preamble Suppression by returning a one in this bit, then the station management entity need not generate preamble for each management transaction.
The DP83848-EP requires a single initialization sequence of 32 bits of preamble following hardware/software reset. This requirement is generally met by the mandatory pullup resistor on MDIO in conjunction with a continuous MDC, or the management access made to determine whether Preamble Suppression is supported.
While the DP83848-EP requires an initial preamble sequence of 32 bits for management initialization, it does not require a full 32-bit sequence between each subsequent transaction. A minimum of one idle bit between management transactions is required as specified in the IEEE 802.3u specification.