RC56D, RC336D, and RC144D Modem Device Sets Designer’s Guide
1154
Conexant
v
4.2.9
THR - TX Buffer (Transmitter Holding Register) (Addr = 0, DLAB = 0)...................................... 4-9
4.2.10
Divisor Registers (Addr = 0 and 1, DLAB = 1) ........................................................................... 4-9
4.2.11
SCR - Scratch Register (Addr = 7)............................................................................................. 4-9
4.3
RECEIVER FIFO INTERRUPT OPERATION......................................................................................... 4-10
4.3.1
Receiver Data Available Interrupt ............................................................................................ 4-10
4.3.2
Receiver Character Timeout Interrupts .................................................................................... 4-10
4.4
TRANSMITTER FIFO INTERRUPT OPERATION ................................................................................. 4-10
4.4.1
Transmitter Empty Interrupt ..................................................................................................... 4-10
5.
DESIGN CONSIDERATIONS ............................................................................................................................. 5-1
5.1
PC BOARD LAYOUT GUIDELINES......................................................................................................... 5-1
5.1.1
General Principles...................................................................................................................... 5-1
5.1.2
Component Placement............................................................................................................... 5-1
5.1.3
Signal Routing............................................................................................................................ 5-2
5.1.4
Board Power Traces .................................................................................................................. 5-3
5.1.5
MCU Power................................................................................................................................ 5-3
5.1.6
MDP Power and Ground ............................................................................................................ 5-3
5.1.7
Ground Planes ........................................................................................................................... 5-3
5.1.8
Crystal Circuit............................................................................................................................. 5-4
5.1.9
Standalone Modem Design with EIA/TIA-232 Interface ............................................................. 5-4
5.1.10
VC and VREF Circuit ................................................................................................................. 5-4
5.1.11
Telephone and Local Handset Interface .................................................................................... 5-5
5.1.12
Optional Configurations ............................................................................................................. 5-5
5.1.13
MDP Specific.............................................................................................................................. 5-5
5.2
DAA TRANSFORMER CONSIDERATION............................................................................................... 5-5
5.3
CRYSTAL/OSCILLATOR SPECIFICATIONS .......................................................................................... 5-7
5.4
SCHEMATICS ........................................................................................................................................ 5-11
6.
PACKAGE DIMENSIONS................................................................................................................................... 6-1
Summary of Contents for RC144D
Page 87: ...INSIDE BACK COVER NOTES ...
