SNLS614A September 2018 – December 2018 DP83869HM
The DP83869HM SMI function supports read or write access to the extended register set using registers REGCR (0x000Dh) and ADDAR (0x000Eh) and the MDIO Manageable Device (MMD) indirect method defined in IEEE 802.3ah Draft for clause 22 for accessing the clause 45 extended register set.
The standard register set, MDIO registers 0 to 31, is accessed using the normal direct-MDIO access or the indirect method, except for register REGCR (0x000Dh) and ADDAR (0x000Eh) which is accessed only using the normal MDIO transaction. The SMI function ignores indirect accesses to these registers.
REGCR (0x000Dh) is the MDIO Manageable MMD access control. In general, register REGCR(4:0) is the device address DEVAD that directs any accesses of ADDAR (0x000Eh) register to the appropriate MMD.
The DP83869HM supports one MMD device address. The vendor-specific device address DEVAD[4:0] = 11111 is used for general MMD register accesses.
All accesses through registers REGCR and ADDAR must use the correct DEVAD. Transactions with other DEVAD are ignored. REGCR[15:14] holds the access function: address (00), data with no post increment (01), data with post increment on read and writes (10) and data with post increment on writes only (11).
The following sections describe how to perform operations on the extended register set using register REGCR and ADDAR. The descriptions use the device address for general MMD register accesses (DEVAD[4:0] = 11111).