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
TBUFFER
10h:7-0
00
Transmit Data Buffer. The host conveys output data to the transmitter in the parallel
mode by writing a data byte to the TBUFFER. Parallel data mode is available in both
synchronous and asynchronous modes. The data is transmitted bit 0 first (see TDBE).
NOTE: Do not read TBUFFER during data mode. RTS must = 1.
TDE
02h:7
1
Tone Detectors Enable. When control bit TDE is set, tone detectors A, B, and C are
enabled; when reset, tone detectors are disabled.
TDBE
1Eh:3
–
Transmit Data Buffer Empty. When set, status bit TDBE signifies that the MDP has
read TBUFFER (10h) and the host can write new data into TBUFFER. This condition
can also cause IRQ to be asserted. The host writing to TBUFFER resets the TDBE and
TDBIA bits. If the host does not write new data into TBUFFER, the MDP sends mark.
TDBE must be a 1 before switching between synchronous, asynchronous, or HDLC
modes. CTS must be on before data is loaded into TBUFFER. If FIFOEN is set,
TDBE, when set, indicates that the transmit FIFO is empty (128-byte extension
disabled) or that more data may continue to be written to TBUFFER (128-byte
extension enabled). (See TDBIE and TDBIA.)
TDBIA
1Eh:7
–
Transmit Data Buffer Interrupt Active. When the transmit data buffer interrupt is
enabled (TDBIE is set) and register 10 is empty (TDBE is set), the MDP asserts IRQ
and sets status bit TDBIA to indicate that TDBE being set caused the interrupt. The
host writing to register 10 resets the TDBIA bit and clears the interrupt request due to
TDBE. (See TDBIE and TDBE.)
TDBIE
1Eh:5
0
Transmit Data Buffer Interrupt Enable. When control bit TDBIE is set (interrupt
enabled), the MDP will assert IRQ and set the TDBIA bit when TDBE is set by the
MDP. When TDBIE is reset (interrupt disabled), TDBE has no effect on IRQ or TDBIA.
(See TDBE and TDBIA.)
TEOF
11h:1
0
HDLC Transmit End of Frame. When operating in HDLC with FIFOEN = 1, the host
must set control bit TEOF to inform the transmitter that the corresponding data is the
last byte in a frame. TEOF must be set prior to loading the last byte in TBUFFER. The
host must reset TEOF prior to loading the next data byte. In voice transmit mode,
TEOF is used to sync the ADPCM decoder (see Section 10). (HDLC = 1, TPDM = 1,
FIFOEN = 1)
TLVL
13h:7-4
9
Transmit Level. The TLVL code selects the transmitter analog output level at the TXA
pin as follows:
TLVL Code (Hex)
TX Output Level (dBm ±0.5 dB)
0
–0.0
1
–1.0
2
–2.0
3
–3.0
4
–4.0
5
–5.0
6
–6.0
7
–7.0
8
–8.0
9
–9.0
A
–10.0
B
–11.0
C
–12.0
D
–13.0
E
–14.0
F
–15.0
The host can fine tune the transmit level by changing a value in DSP RAM.
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