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STANDARD PRODUCT
PM4351 COMET
DATA SHEET
PMC-1970624
ISSUE 10
COMBINED E1/T1 TRANSCEIVER
PROPRIETARY AND CONFIDENTIAL
160
This bit is ignored when in E1 mode or in T1 mode when FPTYP is a logic 0.
FPTYP:
The frame pulse type (FPTYP) bit determines the type of frame pulse on
BTFP. When FPTYP is a logic 0, basic frame alignment is chosen and frame
pulses occur every frame. When FPTYP is a logic 1, multiframe alignment is
chosen.
In T1 mode, with multiframe alignment pulses (FPMODE logic 0) or is
expected (FRMODE logic 1) every 12 or 24 frames as determined by the
ESF_EN bit.
In E1 mode, with multiframe alignment when FPMODE is a logic 0, as an
output BTFP pulses once every 16 frames to indicate both CRC and signaling
multiframe alignment. When BTFP is configured as an input, must be
brought high to mark bit 1 of frame 1 of every 16 frame signaling multiframe
and brought low following bit 1 of frame 1 of every 16 frame CRC multiframe.
To properly initialize the transmit HDLC controllers in basic frame alignment
mode (FPTYP is logic 0), multiframe alignment (FPTYP is logic 1) must be
configured for at least one multiframe (i.e., for at least one multiframe period
in frame pulse master mode or for at least one input frame pulse in frame
pulse slave mode). After this initialization, the FPTYP can be set to any
desired value.
FPMODE:
The frame pulse mode (FPMODE) bit determines whether BTFP is an input
or an output. When FPMODE is a logic 0, frame pulse master mode is
selected and BTFP is an output. When FPMODE is a logic 1, frame pulse
slave mode is selected and BTFP is an input. Frame pulse master mode
cannot be used with transmit backplane clock rates greater than 2.048 MHz.