73M2901/3.3V
Advanced Single
Chip Modem
FIRMWARE DESCRIPTION2
FIRMWARE FEATURES
An “AT” command interpreter provides command
and configuration of the 73M2901/3.3V. This
provides the user a uniform interface to control the
modem in embedded applications.
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“AT” command set
Supports data standards through V.22bis
Provides DAA control firmware (e.g. ring detect,
hook control, line in use detection support)
Multinational Call progress support (FCC68,
CTR21, JATE…)
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The signal processing is performed by obtaining
data from and providing data to the integrated A/D
converter. A MAC hardware processor is provided
for computation.
Caller ID capability
FSK demodulation (V23 or Bell202)
Intra 1st/2nd ring CID data operations
Post Line reversal CID data operations
Interfaces with standard V.24/EIA-232 (3-5 volt
inverted level) serial interface using the built in
serial port and firmware control of port pins
Provides tone generation and detection, four
imprecise and four precise call progress detect
filters
To provide maximum flexibility, the system host
processor can access the internal RAM and Control
Register space in the modem. This will allow the
OEM user to modify parameters such as filter
response, transmit levels through the AT command
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set using proprietary commands.
The host
processor can also access the modem I/O port pins,
providing extended I/O capability.
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Host access to program RAM provided
User access to modem functions
FIRMWARE REQUIREMENTS
The modem always powers up in the idle (on hook)
mode. “AT” commands are issued via the serial
interface from the host. All modem configuration
commands are received in this manner. The data
modem firmware is contained in an internal ROM.
The firmware will automatically enter a power saving
idle mode if the modem is on hook and there are no
incoming host commands.
The modem
automatically powers up upon receiving the next
command. This power up sequence occurs without
delay to the host. This function, while saving power,
is transparent to the host processor and can be
disabled by the host via an “AT” command. The
host can also program the modem to power down
via external pin (DTR) or via a firmware command.
2 For a detailed description of the firmware consult the TDK
73M2901 User’s Manual.
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TDK [ TDK ELECTRONICS ]
