
V.90/K56flex Modem Device Sets with SmartDAA Technology for Low Power Applications 
SmartACFL
Doc. No. 100444A
Conexant
7
Proprietary Information
Hardware Description
SmartDAA
 technology (patent pending) eliminates
the need for a costly analog transformer, relays, and
opto-isolators that are typically used in discrete DAA
implementations. The programmable SmartDAA
architecture simplifies product implementation in
worldwide markets by eliminating the need for
country-specific components.
Microcontroller (MCU/MCUP)
The microcontroller is a Conexant 8-bit
microcomputer with pins to support serial
DTE/parallel host bus/PC Card, MDP, voice/TAM,
speakerphone, and RCDSVD SCP interface
operation. The operating voltage is +3.3V with +5V
tolerant inputs.
The MCUP incorporates a built-in PC Card interface
and CIS memory allowing the MCUP to directly
connect to the PC Card 68-pin socket without
requiring external PICA and CIS devices.
The MCU connects to the DTE/host via a V.24
(EIA/TIA-232-E) serial DTE interface or a parallel
host bus depending on installed firmware, whereas
the MCUP connects to a PC Card socket via built-in
PC Card interface. Unless otherwise stated,
references to general microcontroller functions
include both the MCUP and MCU.
The MCU performs the command processing and
host interface functions. The crystal frequency is
28.224 MHz. The MCU outputs a 28.224 MHz clock
to the MDP eliminating need for a separate MDP
crystal circuit.
The MCU connects to the MDP via dedicated lines
and the external bus. The external bus also connects
to OEM-supplied RAM (56 models), ROM/flash
ROM, and to the optional RCDSVD SCP.
The MCU connects to a serial EEPROM over a
dedicated serial interface.
Two independent functions are supported; the
modem function and an optional user-defined
Function 2. A Card Option Configuration Register
and a Configuration and Status Register for each
function allow independent configuration/control and
status reporting of the respective function.
The MCUP PC Card interface features include:
 PC Card interface logic and memory
 Internal 512-byte Card Information Structure
(CIS) provides the tuple information needed to
define the PC Card functionality.
 CIS Table is configurable from ROM/flash
memory (default) or from NVRAM (option)
 Address decode logic
 Modem Function
 Decoding for standard COM ports in
Overlapping I/O Address Mode
 Independent I/O Address Mode support
 Power-down mode control
 Digital speaker pass-through
 Supports two ring handling methods
 Ring Indicate pass-through to Status Change
 Six 8-bit Modem Function Card Configuration
Registers
Configuration Option Register (full support)
Configuration and Status Register (full support)
Pin Replacement Register (CREADY and
RREADY)
Extended Status Register (RIEvt and RIEnab)
I/O Base Register 0
I/O Base Register 1
 Optional User-defined Function 2
 Reset and chip select control
 Power-down mode control
 16-bit data transfer control
 Disable EEPROM control
 Interrupt request pass through
 Four 8-bit Card Configuration Registers
Configuration Option Register (full support)
Configuration and Status Register (full support)
I/O Base Register 0
I/O Base Register 1
 MCU and MCUP packaged in 128-pin TQFP