Rainbow Electronics DS2154 - Manual (Page 40)

DS2154
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9.0 CLOCK BLOCKING REGISTERS
The Receive Channel blocking Registers (RCBR1 /
RCBR2 / RCBR3 / RCBR4) and the Transmit Channel
Blocking Registers (TCBR1 / TCBR2 / TCBR3 / TCBR4)
control RCHBLK and TCHBLK pins respectively. (The
RCHBLK and TCHBLK pins are user programmable
outputs that can be forced either high or low during indi-
vidual channels). These outputs can be used to block
clocks to a USART or LAPD controller in ISDN–PRI
applications. When the appropriate bits are set to a one,
the RCHBLK and TCHBLK pin will be held high during
the entire corresponding channel time. See the timing in
Section 13 for an example. The TCBRs have alternate
mode of use. Via the CCR3.6 bit, the user has the option
to use the TCBRs to determine on a channel by channel
basis, which signaling bits are to be inserted via the
TSRs (the corresponding bit in the TCBRs=1) and
which are to be sourced from the TSER or TSIG pins
(the corresponding bit in the TCBR=0). See Section 7
for more details about this mode of operation.
RCBR1/RCBR2/RCBR3/RCBR4: RECEIVE CHANNEL BLOCKING REGISTERS
(Address=2B to 2E Hex)
(MSB) (LSB)
CH8 CH7 CH6 CH5 CH4 CH3 CH2 CH1
CH16 CH15 CH14 CH13 CH12 CH11 CH10 CH9
CH24 CH23 CH22 CH21 CH20 CH19 CH18 CH17
CH32 CH31 CH30 CH29 CH28 CH27 CH26 CH25
SYMBOL POSITION NAME AND DESCRIPTION
CH32 RCBR4.7 Receive Channel Blocking Registers.
0=force the RCHBLK pin to remain low during this channel time
CH1 RCBR1.0 1=force the RCHBLK pin high during this channel time
TCBR1/TCBR2/TCBR3/TCBR4: TRANSMIT CHANNEL BLOCKING REGISTERS
(Address=22 to 25 Hex)
(MSB) (LSB)
CH8 CH7 CH6 CH5 CH4 CH3 CH2 CH1
CH16 CH15 CH14 CH13 CH12 CH11 CH10 CH9
CH24 CH23 CH22 CH21 CH20 CH19 CH18 CH17
CH32 CH31 CH30 CH29 CH28 CH27 CH26 CH25
SYMBOL POSITION NAME AND DESCRIPTION
CH32 TCBR4.7 Transmit Channel Blocking Registers.
0=force the TCHBLK pin to remain low during this channel time
CH1 TCBR1.0 1=force the TCHBLK pin high during this channel time
NOTE:
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.
RCBR1 (2B)
RCBR2 (2C)
RCBR3 (2D)
RCBR4 (2E)
TCBR1 (22)
TCBR2 (23)
TCBR3 (24)
TCBR4 (25)