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GT-96100A Advanced Communication Controller
382
Revision 1.0
7:0
MASK
Mask pattern for the current data.
Definition of this field is dependent on B (byte/bit) setting.
B=1 (byte mode)
In byte mode each bit in the MASK field defines the mask for the corre-
sponding bit in the data.
1 - TDM transmit data is driven out, receive data is processed nor-
mally.
0 - TDM transmit data is not driven out (transmit output is tri-
stated), receive data is ignored.
B=0 (bit mode)
In bit mode only bits 5:0 are valid. Bits 7:6 must be set to ‘0’.
Bits 1:0 define the mask for the current bit:
00 - Z
Transmit output is tri-state. Receive data is ignored.
01 - 0
Transmit output is forced low. Receive data is ignored.
10 - D
Transmit data driven out. Receive data is processed normally.
11 - 1 (transmit output is forced high, receive data is ignored)
Bit 2 serves as the D channel bit. Setting this bit to ‘1’ marks this time slot as
a D channel time slot. This bit identifies the MPSC to which the TDM must
assert or de-assert the internal CTS signal based on the recent sampled
value of the Dgrant bit (see below).
If Dgrant is sampled low, CTS is asserted.
If Dgrant is sampled high, CTS is deasserted.
If Dgrant is deasserted while a D channel frame is being transmit-
ted, the MPSC connected to the D channel stops transmission (due
to CTS lost) and initiates a collision resolution procedure.
Bit 3 - Dgrant/Dreq
In a received frame, this bit serves as the Dgrant bit. An IOM (GCI) PHY
uses this bit to signal the GT-96100A that it has access to the D channel. In
a transmit frame, it serves as the Dreq bit. The GT-96100A drives the Dreq
bit to ‘0’ when sending data on the D channel. When not sending data on the
D channel, Dreq is driven according to the value programmed in MASK[1:0]
bits.
Bit 4 identifies the current bit as the IOM-2 MX bit. The GT-96100A recog-
nizes an inactive-to-active transition of received MX bit as an indication that
valid IOM-2 monitor data is driven by the PHY.
Bit 5 identifies the current bit as the IOM-2 MR bit. The GT-96100A recog-
nizes an inactive-to-active transition of received MR bit as an indication that
IOM-2 monitor data, sent by the GT-96100A, have been sampled by the
PHY.
X
Table 356: Flex TDM DPRAM Entry (Continued)
Bits
Field
Name
Fun ction
Reset
Value