PRELIMINARY
PM4318 OCTLIU
DATASHEET
PMC- 2001578
ISSUE 3
OCTAL E1/T1/J1 LINE INTERFACE DEVICE
Register 068H, 0E8H, 168H, 1E8H, 268H, 2E8H, 368H, 3E8H: XLPG Control/Status
Bit
Type
Function
Default
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
R/W
R/W
HIGHZ
ARST
1
0
X
0
X
0
0
1
Unused
R/W
R
INITRAM
OVRFLW
Reserved
Reserved
Reserved
R/W
R/W
R/W
HIGHZ:
The HIGHZ bit controls tristating of the TXTIP[x] and TXRING[x] outputs. When the HIGHZ
bit is set to a logic 0, the outputs are enabled. When the HIGHZ bit is set to a logic 1, the
outputs are put into high impedance. Setting HIGHZ to logic 1 has the same effect as setting
SCALE[4:0] to 00H.
ARST:
The Analogue Reset bit (ARST) resets the analogue portion of the XLPG (without affecting
the digital portion) when set to logic 1.
INITRAM:
The Waveform Storage RAM initialisation bit (INITRAM) causes the XPLG waveform storage
RAM to be initialised to 12 standard waveform patterns when set to logic 1. This bit remains
at logic 1 while the initialisation is in progress and is cleared to logic 0 when the initialisation
has completed.
The 12 waveform patterns to which the RAM is initialised are listed in Table 20 thru Table 29,
Table 37 and Table 38.
OVRFLW:
The overflow detection value bit (OVRFLW) indicates the presence or absence of an overflow
condition in the waveform computation pipeline. An overflow occurs when the sum of the five
unit interval (UI) samples exceeds the maximum D/A value. The XLPG detects overflows and
saturates the output value to minimize their impact on the output signal. Overflows can easily
be eliminated by changing the waveform programming. This status bit is set to logic 1 when
an overflow condition is detected and it is reset to logic 0 only when this register is read. It is
suggested that this register be read twice after the programming of a new waveform and
transmission of data to ensure the maximum output amplitude is never exceeded.
PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMERS’ INTERNAL USE
146
PMC [ PMC-SIERRA, INC ]
