cx28500 Mindspeed Technologies, cx28500 Datasheet - Page 45

• Manufacturer Part Number: cx28500
• Description: Cx28500 Multichannel Synchronous Communications Controller
• Manufacturer: Mindspeed Technologies

Table 1-8.
28500-DSH-002-C
TSYNC[31:0]/
TSTUFF[31:0]
TCLK[31:0]
Pin Label
CX28500 Hardware Signal Definitions (2 of 7)
TSBUS Transmit Stuff
Synchronization/
Signal Name
Transmit Clock
Transmit
Mindspeed Proprietary and Confidential
Mindspeed Technologies
I/O
I
I
If the serial port is configured in conventional mode, then TCLK controls
the rate at which data is transmitted and synchronizes transitions for
TDATx and sampling of TSYNCx and CTSx, if CTSxis enabled. If the port
is configured as a TSBUS port, then TCLK controls the rate at which data
is transmitted and synchronizes transitions for TDATx and sampling of
TSTUFFx and STBx (STBx only for transmit circuitry).
If the serial port is configured in conventional mode, then this signal is
defined as TSYNC. TSYNC is sampled on the specified active edge of the
corresponding TCLKx clock. (See TSYNC_EDGE bit field in
36, TSIU Port Configuration
When TSYNCx signal goes from low to high then the start of transmit
frame is indicated.
TSYNCx is ignored if the serial port is configured to operate in
unchannelized mode.
If the serial port is configured in T1 mode, then the corresponding data
bit that latched out during the same bit time period (but not necessarily
sampled at the same clock edge) is the F-bit of the T1 frame.
If the serial port is configured in channelized mode, then the
corresponding data bit that latched out during the same bit time period
(but not necessarily sampled at the same clock edge) is Bit-0 of the first
time slot of the N×64 frame.
Since CX28500’s flywheel mechanism is always used in channelized
mode, no other synchronization signal is required to track the start of
each subsequent frame. However, if a SYNC pulse, if it exists, occurs
anywhere but at the frame boundaries, which are tracked by the flywheel
mechanism, a COFA is generated for that port.
If the port is configured to operate as TSBUS port, then this signal is
defined as TSTUFF. The TSTUFF values are to either stuff (no TDAT
output) or not stuff (TDAT valid).
TSTUFF is sampled on the specified active edge of the corresponding
TCLKx. (See TSTUFF_EDGE bit field in
Configuration
If the serial port operates in channelized TSBUS mode, then TSTUFF
assertion indicates that no data needs to be transmitted in the 8th time
slot after the assertion of the TSTUFF.
Note that while operating in channelized TSBUS mode, CX28500 requires
the following:
1.
2.
The stuff status for each time slot to be presented at its TSTUFF
input exactly eight time slots in advance of the actual time slot
for which the stuff status is to be applied. The amount of the
TSTUFF advance is fixed at eight time slots, even though the
number of time slots within a frame may vary.
Assertion of this signal anytime during the time slot is required.
But, for good practice, it is recommended that this signal is
asserted within the first two bits of the time slot.
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Register.)
Register.)
Definition
Table 6-36, TSIU Port
Introduction
Table 6-
30