Seagate Fibre Channel Interface - Manual (Page 119)

Fibre Channel Interface Manual, Rev. D 105
10.3.2 8067 ESI interface pinouts
In 8067, the ESI function becomes a bi-directional interface. Three pins are defined for control functions and
the remaining four pins become a 4-bit nibble interface. Table 58 is a mapping of the Select pins to the 8067
ESI interface function. 8067 specifies that open-collector type drivers be used for signals on the P_ESI and
Select lines.
10.3.3 8067 information format
ESI in 8067 mode is transferred on the ESI interface a nibble (4 bits) at a time. Refer to Table 59 for the trans-
fer order in bits and Table 60 for byte order.
Table 58: SFF 8067 ESI pinouts
Pin ESI function
SEL 6
–DSK_WR
SEL 5
–DSK_RD
SEL 4
–ENCL_ACK
SEL 3
Data (3)
SEL 2
Data (2)
SEL 1
Data (1)
SEL 0
Data (0)
Table 59: Bit order in 8067 mode ESI transfers
MSB LSB
Bit order byte 7 6 5 4 3 2 1 0
Transfer order on ESI interface First Nibble Second Nibble
Bit order is ESI data D(3) D(2) D(1) D(0) D(3) D(2) D(1) D(0)
Table 60: Byte order in 8067 mode ESI transfers
Byte order in SCSI transfer 0 1 .......... n – 1 n
Byte order is ESI transfer first second .......... n – 1 n