RCVDL56DPFL/SP, RCV56DPFL/SP, and RCV336DPFL/SP Designer’s Guide
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Table 3-1. Interface Memory Bit Definitions (Cont’d)
Mnemonic
Location
Default
Name/Description
RBUFFER
00h:7-0
–
Receive Data Buffer. The host obtains channel data from the MDP receiver in the
parallel data mode by reading a data byte from the RBUFFER. The RBUFFER contains
the received data when the RDBF bit is set. (See RDBF, RDBIE, and RDBIA.)
RDBF
1Eh:0
–
Receive Data Buffer Full. When set, status bit RDBF signifies that the receiver wrote
valid data into RBUFFER (00h). This condition can also cause IRQ to be asserted. The
host reading RBUFFER resets the RDBF and RDBIA bits. (See RDBIE and RDBIA.)
RDBIA
1Eh:6
–
Receive Data Buffer Interrupt Active. When the receive data buffer interrupt is
enabled (RDBIE is set) and RBUFFER (00h) is written to by the MDP (RDBF is set),
the MDP asserts IRQ and sets RDBIA to indicate that RDBF being set caused the
interrupt. The host reading RBUFFER resets the RDBIA bit and clears the interrupt
request due to RDBF. (See RDBF and RDBIE.)
RDBIE
1Eh:2
0
Receive Data Buffer Interrupt Enable. When control bit RDBIE is set (interrupt
enabled), the MDP will assert IRQ and set the RDBIA bit when RDBF is set by the
MDP. When RDBIE is reset (interrupt disabled), RDBF has no effect on IRQ or RDBIA.
(See RDBF and RDBIA.)
RDL
07h:6
0
Remote Digital Loopback. When set, control bit RDL causes the MDP to initiate a
V.22 bis request for the remote modem to go into digital loopback; RXD is clamped to
a mark and the CTS bit and ~CTS signal will be reset in the local MDP until the loop is
established. The RDLE bit should be set before setting the RDL bit. (V.22 bis, V.22,
Bell 212A/1200)
RDLE
07h:7
1
Remote Digital Loopback Response Enable. When set, control bit RDLE enables
the MDP to respond to another modem's V.22 bis remote digital loopback request, thus
going into loopback. When this occurs, the MDP clamps RXD to mark; resets the CTS,
DSR and RLSD bits, and turns the ~CTS, ~DSR and ~RLSD signals to logic 1. The TM
bit is set to inform the host of the test status.
When the RDLE bit is reset, no response will be generated. (V.22 bis)
RDWK
15h:5
1
Ring Detect Wake up. When control bit RDWK is set and the MDP is in sleep mode,
an incoming ring signal on the RINGD pin will bring the MDP out of sleep mode. The
RINGD pin must be normally low for the RDWK function to work. (See SLEEP bit).
RI
0Fh:3
–
Ring Indicator. When set, status bit RI indicates that a ringing signal is being
detected. Ringing is detected if pulses are present on the RINGD input in the 15 Hz–68
Hz frequency range. The RI bit follows the ringing signal with a 1 during the ON time
and a 0 during the OFF time coincident with ~RI output signal. The decision bounds
are host programmable in DSP RAM. This bit is valid only when DATA bit is reset and
is not applicable in tone modes.
RIEN
1Ah:6
0
RION Enable. When control bit is a 1, the ~RI output will reflect the RION bit. When a
0, the ~RI output follows the ringing signal on the RINGD input.
RION
1Ah:5
0
Ring Indicator On. Control bit RION determines the state of the ~RI output (1 = low; 0
= high) when bit RIEN is set and the DATA bit is reset.
RLSD
0Fh:7
–
Received Line Signal Detector. When status bit RLSD is set, the MDP has finished
receiving the training sequence or has turned on due to detected energy above
threshold, and is receiving data. RLSD is reset when the MDP is in the idle state and
during the reception of a training sequence. The RLSD threshold may be adjusted in
DSP RAM.
RLSDE
03h:4
1
RLSD Enable. When control bit RLSDE is set, the ~RLSD pin reflects the RLSD bit
state. When RLSDE is reset, the ~RLSD pin is clamped OFF and data is clamped to a
mark regardless of the state of the RLSD bit.
RREDT
0Eh:5
–
Rate Renegotiation Detected. When set, status bit indicates a rate renegotiation
sequence has been detected. RREDT will remain on until the host resets it. (K56flex,
V.34, V.32 bis, V.32)
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