STANDARD PRODUCT
PM4351 COMET
DATA SHEET
PMC-1970624
ISSUE 10
COMBINED E1/T1 TRANSCEIVER
Register 041H: BTIF Frame Pulse Configuration
Bit
Type
Function
Default
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
R/W
MAP
Unused
Unused
Unused
FPINV
0
X
X
X
0
0
0
1
R/W
R/W
R/W
R/W
ESF_EN
FPTYP
FPMODE
MAP:
The MAP bit determines the mapping of a 2.048 MHz backplane onto a
1.544 MHz line. This bit is ignored when in E1 mode (E1/T1B register bit is
logic 1), when the backplane rate is 1.544 Mbit/s (RATE[1:0] = 'b00), or when
in clock master mode (CMODE = 'b0).
When MAP is a logic 0, every fourth time slot is unused, starting with time slot
0. The framing bit is sampled during bit 0 of time slot 0, so that only bits 1 to
7 of time slot 0 are ignored.
When MAP is a logic 1, the first 24 time slots (0 to 23) are sampled. The
framing bit is sampled during bit 7 of time slot 31 and the rest of the frame
(time slots 24 to 30 and bits 0 to 6 of time slot 31) are ignored.
FPINV:
The frame pulse inversion (FPINV) bit determines whether BTFP is inverted
prior to sampling. If FPINV is a logic 0, BTFP is active high. If FPINV is a
logic 1, BTFP is active low. Frame pulse inversion cannot be used when
BTFP is configured as an output (FPMODE is a logic 0).
ESF_EN:
The extended superframe enable (ESF_EN) bit determines which superframe
alignment is used when in T1 mode and FPTYP is a logic 1. When ESF_EN
is a logic 0, superframe alignment is chosen and BTFP pulses (FPMODE
logic 0) or is expected (FPMODE logic 1) every 12 frames. When ESF_EN is
a logic 1, extended superframe alignment is chosen and pulses (FPMODE
logic 0) or is expected (FPMODE logic 1) every 24 frames.
PROPRIETARY AND CONFIDENTIAL
159
PMC [ PMC-SIERRA, INC ]
