JAJSEV0G july 2016 – august 2023 DP83822H , DP83822HF , DP83822I , DP83822IF
PRODUCTION DATA
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The DP83822 SMI function supports read and write access to the extended register set using the Register Control Register (REGCR, address 0x000D), the Data Register (ADDAR, address 0x000E), 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 and register ADDAR, which are accessed only using the normal MDIO transaction. The SMI function will ignore indirect access to these registers.
REGCR is the MMD access control. In general, register REGCR[4:0] is the device address DEVAD that directs any accesses of the ADDAR register to the appropriate MMD.
The DP83822 supports three MMD device addresses:
All accesses through register 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 writes only (11). Address (10) is not valid.
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). For register accesses to the MMD3 or MMD7 registers the corresponding device address would be used.