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EMAC Functional Architecture
The implementation of these macros using the register layer Chip Support Library (CSL) is shown in Example 3 (USERACCESS0 is assumed).
Note that this implementation does not check the ACK bit on PHY register reads; in other words, it does not follow the procedure outlined in Section 2.7.2.3. As the ALIVE register initially selects a PHY, it is assumed that the PHY is acknowledging read operations. It is possible that a PHY could become inactive at a future point in time. For example, a PHY can have its MDIO addresses changed while the system is running, although it is not a common occurrence. This condition can be tested by periodically checking the PHY state in the ALIVE register.
Example 3. MDIO Register Access Macros
#define PHYREG_read(regadr, phyadr) | 
  | \  | 
 | 
  | \  | 
CSL_FMK(MDIO_USERACCESS0_GO,1u)  | \  | |
CSL_FMK(MDIO_USERACCESS0_REGADR,regadr)  | \  | |
CSL_FMK(MDIO_USERACCESS0_PHYADR,phyadr)  | 
  | 
  | 
#define PHYREG_write(regadr, phyadr, data) | 
  | \  | 
  | \  | |
CSL_FMK(MDIO_USERACCESS0_GO,1u)  | \  | |
CSL_FMK(MDIO_USERACCESS0_WRITE,1) | \  | |
CSL_FMK(MDIO_USERACCESS0_REGADR,regadr)  | \  | |
CSL_FMK(MDIO_USERACCESS0_PHYADR,phyadr)  | \  | |
CSL_FMK(MDIO_USERACCESS0_DATA, data)  | 
  | 
  | 
#define PHYREG_wait()  | 
  | \  | 
while 
#define PHYREG_wait Results(results ) { | \  | 
while 
42  | Ethernet Media Access Controller (EMAC)/Management Data Input/Output (MDIO)  | SPRU975B   |