CX81801-7x/8x SmartV.XX Modem Data Sheet
3.1.2
3.1.3
3.1.4
Serial Interface Configuration Only................................................................................................................. 3-2
3.1.2.1
Parallel Interface Configuration Only (PARIF = High)..................................................................................... 3-3
3.1.3.1 Parallel Host Bus Interface......................................................................................................... 3-3
CX81801 Modem Interface Signals................................................................................................................ 3-3
Serial DTE Interface and Indicator Outputs (PARIF = Low)........................................................ 3-2
3.2
CX20493 LSD Hardware Pins and Signals ................................................................................................................... 3-22
3.2.1
CX20493 LSD Signal Summary.................................................................................................................... 3-22
3.2.1.1
3.2.1.2
3.2.1.3
3.2.1.4
3.2.1.5
Smart Modem Interface (Through DIB) ................................................................................... 3-22
Telephone Line Interface .......................................................................................................... 3-22
Voltage References................................................................................................................... 3-22
General Purpose Input/Output.................................................................................................. 3-23
No Connects............................................................................................................................. 3-23
3.2.2
CX20493 LSD Pin Assignments and Signal Definitions ............................................................................... 3-23
3.3
CX20442 VC Hardware Pins and Signals (S Models)................................................................................................... 3-28
3.3.1
CX20442 VC Signal Summary...................................................................................................................... 3-28
3.3.1.1
3.3.1.2
3.3.1.3
3.3.1.4
Speakerphone Interface............................................................................................................ 3-28
Telephone Handset/Headset Interface...................................................................................... 3-28
CX81801 Modem Interface....................................................................................................... 3-28
Host Interface........................................................................................................................... 3-28
3.3.2
CX20442 VC Pin Assignments and Signal Definitions ................................................................................. 3-29
3.4
3.5
Electrical and Environmental Specifications................................................................................................................. 3-35
3.4.1
3.4.2
Operating Conditions, Absolute Maximum Ratings, and Power Requirements ........................................... 3-35
Interface and Timing Waveforms ................................................................................................................. 3-37
3.4.2.1
3.4.2.2
3.4.2.3
External Memory Bus Timing................................................................................................... 3-37
Parallel Host Bus Timing.......................................................................................................... 3-39
Serial DTE Interface.................................................................................................................. 3-41
Crystal Specifications ................................................................................................................................................... 3-42
4. Package Dimensions ............................................................................................................................4-1
5. Parallel Host Interface ..........................................................................................................................5-1
5.1
Overview......................................................................................................................................................................... 5-1
5.2
Register Signal Definitions ............................................................................................................................................. 5-3
5.2.1
5.2.2
5.2.3
5.2.4
5.2.5
5.2.6
5.2.7
5.2.8
5.2.9
5.2.10
IER - Interrupt Enable Register (Addr = 1, DLAB = 0).................................................................................... 5-3
FCR - FIFO Control Register (Addr = 2, Write Only)....................................................................................... 5-4
IIR - Interrupt Identifier Register (Addr = 2) .................................................................................................. 5-5
LCR - Line Control Register (Addr = 3).......................................................................................................... 5-6
MCR - Modem Control Register (Addr = 4).................................................................................................... 5-7
LSR - Line Status Register (Addr = 5)............................................................................................................ 5-7
MSR - Modem Status Register (Addr = 6) ..................................................................................................... 5-9
RBR - RX Buffer (Receiver Buffer Register) (Addr = 0, DLAB = 0) ................................................................ 5-9
THR - TX Buffer (Transmitter Holding Register) (Addr = 0, DLAB = 0).......................................................... 5-9
Divisor Registers (Addr = 0 and 1, DLAB = 1).............................................................................................. 5-10
5.3
5.4
Receiver FIFO Interrupt Operation ................................................................................................................................ 5-10
5.3.1
5.3.2
Receiver Data Available Interrupt ................................................................................................................. 5-10
Receiver Character Timeout Interrupts......................................................................................................... 5-11
Transmitter FIFO Interrupt Operation ........................................................................................................................... 5-11
5.4.1 Transmitter Empty Interrupt......................................................................................................................... 5-11
102199B
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