PRELIMINARY
PM4318 OCTLIU
DATASHEET
PMC- 2001578
ISSUE 3
OCTAL E1/T1/J1 LINE INTERFACE DEVICE
Figure 16 – Serial PROM Command Format
Reg[13:8]
Reg[7:0]
Data[7:0]
Code1 Code0
Reg[13:0] specifies one of the OCTLIU registers defined in Table 4. Data[7:0] is the value to be
written to the specified register. Commands are interpreted depending on the Code1 and Code0
bits as follows:
Table 2
– Serial PROM Commands – Code Bits
Code1
Code0
Action
0
0
1
1
0
1
0
1
Special Command
Write Data[7:0] to Reg[13:0] only if SRCODE = 0
Write Data[7:0] to Reg[13:0] only if SRCODE = 1
Write Data[7:0] to Reg[13:0] regardless of value of
SRCODE
The SRCODE input to OCTLIU provides a means to execute configuration instructions
conditionally. Two different configuration sequences can be stored in a single PROM (for T1 or
E1 operation, for example) and the SRCODE input used to select which one will be applied.
Different OCTLIU devices in a cascade can have their SRCODE inputs set to different values.
When Code1 = Code0 = ‘0’, the Reg[13:0] and Data[7:0] fields are interpreted as a special
command, not as a register/data pair. The following special commands are defined:
Table 3
– Serial PROM Special Commands
Reg[13:0]
3FFB
Action
Resume acting upon register write commands. Only meaningfull if a 3FFD
command (see below) has previously been received.
3FFC
3FFD
No-op.
Ignore subsequent register write commands. This command is only acted
upon by the first OCTLIU in the cascade which receives it and which is not
already ignoring register write commands. The OCTLIU which acts upon this
command does not propagate the command down the cascade, but instead
substitutes the 3FFC special command.
PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMERS’ INTERNAL USE
47
PMC [ PMC-SIERRA, INC ]
