Programmable Four-Channel Communications Controller
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CD2481
Datasheet
9
1.0
Features
Four full-duplex multi-protocol channels, each running up to 230.4 kbps (with 60-MHz clock)
Microcode downloadable to on-chip storage supports various asynchronous and synchronous
protocols on all channels
32-bit address, 16-bit data, double-buffered DMA (direct memory access) controller for each
transmitter and receiver; two independent bit-rate generators per channel for transmit and
receive
On-chip NRZ (nonreturn-to-zero), NRZI (nonreturn-to-zero inverted), and Manchester data
encoding and decoding
DPLL (digital phase locked loop) on each receiver
Two independent timers per channel
Protocols Supported
PPP (Point-to-Point Protocol) Features
Supports data link level
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RFC-1661
Supports dual async control character maps (32 control characters)
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RFC-1662
Compatible with ISO 3309/4335 Addendum 1
Automatic insertion/deletion of control/escape characters and bit complements
Automatic generation and detection of 16-bit FCS (frame check sequence)
HDLC/SDLC (Non-Multidrop) Features
Four 8-bit or two 16-bit frame address matching
FCS generation and validation
Programmable leading-pad character transmission
Supports shared flags on receive frames
Programmable number of leading flags
Asynchronous Features
User-programmable and automatic flow control modes
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In-band (software) by XON/XOFF
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Out-of-band (hardware flow control) by RTS/CTS and DTR/DSR
Line-break detection and generation
Special-character and character-range recognition and transmission
Transmit delay
5- to 8-bit character plus optional parity