RFX144V24-S23 and RFX96V24-S23 Modem Designer’s Guide
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3.2.3 8-Bit Audio Mode Operation
The 8-bit Audio Mode operates when CONF = 82h.
Tone Detectors
All tone detectors are functional in this mode.
8-Bit Audio Mode Transmitter
This mode allows the transmission of 8-bit audio messages.
8-bit Audio Mode transmitter operates when CONF = 82h and the RTSP bit is a 1. The host must also disable RAM Access 1
(i.e., reset ACC1 to a 0). DTMF detection is available.
The value in register 00 is sent to the D/A converter for transmission. The modem sets the B1A bit every sample time to
indicate that the value in register 00 has been transmitted. B1A is reset when the host writes the next byte.
8-Bit Audio Mode Receiver
This mode allows the recording of 8-bit audio messages.
8-bit Audio Mode receiver operates when CONF = 82h and the RTSP bit is a 0.
The host reads the A/D sample from register 00 using the DSP RAM Access Code No. 2 (Table 4-1). Reading the A/D
sample simultaneously resets the B1A bit.
The slew rate is set to zero upon entering this configuration. After configuring the modem, the host must immediately write
an AGC Slew Rate to DSP RAM. The AGC gain may be changed by writing to the AGC Gain Word and the maximum AGC
gain may be changed by writing to the Receiver Sensitivity (MAXG). (See Section 4.2.)
3.2.4 16-Bit Audio Mode Operation
The 16-bit Audio Mode operates when CONF = 86h.
Tone Detectors
All tone detectors are functional in this mode.
16-Bit Audio Mode Transmitter
This mode allows the transmission of high quality 16-bit audio messages.
16-bit Audio Mode transmitter operates when CONF = 86h and the RTSP bit is a 1. The host must also disable RAM Access
1 (i.e., reset ACC1 to a 0). DTMF detection is available.
The values in registers 01 (most significant byte) and 00 (least significant byte) are sent to the D/A converter for
transmission. The modem sets the B1A bit every sample time to indicate that the values in registers 00 and 01 have been
transmitted. B1A is reset when the host writes the least significant byte into register 00; therefore, it is recommended that
the most significant byte first be written to register 01 followed by the least significant byte to register 00.
16-Bit Audio Mode Receiver
This mode allows the recording of high quality 16-bit audio messages.
16-bit Audio Mode receiver operates when CONF = 86h and the RTSP bit is a 0.
The host reads the A/D sample from registers 01 (most significant byte) and 00 (least significant byte). B1A is reset when
the host reads the least significant byte from register 00; therefore, it is recommended that the most significant byte first be
read from register 01 followed by the least significant byte from register 00.
The slew rate is set to zero upon entering this configuration. After configuring the modem, the host must immediately write
an AGC Slew Rate to DSP RAM. The AGC gain may be changed by writing to the AGC Gain Word and the maximum AGC
gain may be changed by writing to the Receiver Sensitivity (MAXG). (See Section 4.2.)
Summary of Contents for RFX144V24-S23
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