Specifications
ASIX ELECTRONICS CORPORATION 
20
 AX88772 
USB to 10/100 Fast Ethernet/HomePNA Controller 
6.2.1  Detailed Register Description 
6.2.1.1 Rx/Tx SRAM Read Register (02h, read only) 
Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 
AA [7:0] 
Reserved B [3:0] 
0h C [3:0] 
DD [7:0] in Data stage 
EE [7:0] in Data stage 
FF [7:0] in Data stage 
GG [7:0] in Data stage 
HH [7:0] in Data stage 
II [7:0] in Data stage 
JJ [7:0] in Data stage 
KK [7:0] in Data stage 
  {B [3:0], AA [7:0]}: The read address of RX or TX SRAM. 
  C [0]: RAM selection. 
  0: indicates to read from RX SRAM. 
  1: indicates to read from TX SRAM. 
  C [3:1]: Reserved. 
{DD [7:0], EE [7:0], FF [7:0], GG [7:0], HH [7:0], II [7:0], JJ [7:0], KK [7:0]}: The 64-bits of data presented in Data 
stage are the data to be written to RX or TX SRAM. 
6.2.1.2 Rx/Tx SRAM Write Register (03h, write only) 
Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 
AA [7:0] 
Reserved B [3:0] 
Reserved C [3:0] 
DD [7:0] in Data stage 
EE [7:0] in Data stage 
FF [7:0] in Data stage 
GG [7:0] in Data stage 
HH [7:0] in Data stage 
II [7:0] in Data stage 
JJ [7:0] in Data stage 
KK [7:0] in Data stage 
    {B [3:0], AA [7:0]}: The write address of RX or TX SRAM. 
  C [0]: RAM selection. 
  0: indicates to write to RX SRAM. 
  1: indicates to write to TX SRAM. 
  C [3:1]: Reserved. 
  {DD [7:0], EE [7:0], FF [7:0], GG [7:0], HH [7:0], II [7:0], JJ [7:0], KK [7:0]}: The 64-bits of data presented in Data 
stage are the data to be written to RX or TX SRAM. 
6.2.1.3 Software Serial Management Control Register (06h, write only) 
When software needs to access to Ethernet PHY’s internal registers, one has to first issue this command to request the 
ownership of Serial Management Interface. The ownership status of the interface can be retrieved from Serial 
Management Status Register. 










