DS21354/DS21554 3.3V/5V E1 Single-Chip Transceivers
9.2.2.
Transmit Side
Via the THSE control bit (CCR3.2), the DS21354/DS21554 can be set up to take the signaling data
presented at the TSIG pin and insert the signaling data into the PCM data stream that is being input at the
TSER pin. The hardware signaling insertion capabilities of each framer are available whether the
transmit-side elastic store is enabled or disabled. If the transmit-side elastic store is enabled, the
backplane clock (TSYSCLK) must be 2.048MHz/4.096MHz/8.192MHz.
When hardware signaling insertion is enabled on a framer (THSE = 1), then the user must enable the
Transmit Channel Blocking Register Function Select (TCBFS) control bit (CCR3.6 = 1). This is needed
so that the CAS multiframe alignment word, multiframe remote alarm, and spare bits can be added to
time slot 16 in frame 0 of the multiframe. The TS1 register should be programmed with the proper
information. If CCR3.6 = 1, then a zero in the TCBRs implies that signaling data is to be sourced from
TSER (or TSIG if CCR3.2 = 1) and a one implies that signaling data for that channel is to be sourced
from the Transmit Signaling (TS) registers. See definition below.
TCBR1/TCBR2/TCBR3/TCBR4: DEFINITION WHEN CCR3.6 = 1
(MSB)
CH18
CH22
CH26
CH30
(LSB)
1*
CH4
CH8
CH12
CH3
CH7
CH11
CH15
CH17
CH21
CH25
CH29
CH2
CH6
CH10
CH14
CH16
CH20
CH24
CH28
CH1
CH5
CH9
CH13
1*
TCBR1(22)
TCBR2(23)
TCBR3(24)
TCBR4(25)
CH19
CH23
CH27
*These bits should be set to one to allow the internal TS1 register to create the CAS Multiframe Alignment Word and Spare/Remote Alarm bits.
The user can also take advantage of this functionality to intermix signaling data from the TSIG pin and
from the internal Transmit Signaling Registers (TS1 to TS16). As an example, assume that the user
wishes to source all the signaling data except for voice channels 5 and 10 from the TSIG pin. In this
application, the following bits and registers would be programmed as follows:
CONTROL BITS
THSE = 1 (CCR3.2)
TCBFS = 1 (CCR3.6)
T16S = 0 (TCR1.5)
REGISTER VALUES
TS1 = 0Bh (MF alignment word, remote alarm etc.)
TCBR1 = 03h (source time slot 16, frame 1 data)
TCBR2 = 01h (source voice Channel 5 signaling data from TS6)
CBR3 = 04h (source voice Channel 10 signaling data from TS11)
TCBR4 = 00h
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