Philips Semiconductors Product data sheet
SC28L198Octal UART for 3.3 V and 5 V supply voltage
2
2006 Aug 10
Table of Contents
Description 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Uses 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Features 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pin Configurations
4. . . . . . . . . . . . . . . . . . . . . . . . .
Pinout 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pin Description 6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Absolute Maximum Ratings 6. . . . . . . . . . . . . . . . .
Block Diagram
7. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Functional Description 7. . . . . . . . . . . . . . . . . . . . .
Conceptual Overview 7. . . . . . . . . . . . . . . . . . . . . . .
Host Interface 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Asynchronous bus cycle 7. . . . . . . . . . . . . . . . . . . . . . . . . . .
Synchronous bus cycle 7. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Timing Circuits 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Crystal Oscillator 8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Sclk – System Clock 8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Baud Rate Generator BRG 8. . . . . . . . . . . . . . . . . . . . . . . .
BRG Counters (Used for random baud rate generation) 8
Channel Blocks 8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Character Recognition 8. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Interrupt Control 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Global Registers 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
I/O Ports 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Detailed Descriptions 9. . . . . . . . . . . . . . . . . . . . . . .
Receiver and Transmitter
9. . . . . . . . . . . . . . . . . . .
Transmitter 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Status Bits 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Transmission of ”break” 10. . . . . . . . . . . . . . . . . . . . . . . . . . . .
1x and 16x modes, Transmitter 10. . . . . . . . . . . . . . . . . . . . .
Transmitter FIFO 10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Receiver 10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1x and 16x mode, Receiver 10. . . . . . . . . . . . . . . . . . . . . . . . .
Receiver Status Bits 10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Receiver FIFO 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
RxFIFO Status: Status reporting modes 11. . . . . . . . . . . . . .
I/O ports 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
General Purpose Pins 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Global Registers 8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Character Recognition 8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Xon Xoff Characters 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Multi-drop or Wake up or 9 bit mode 12. . . . . . . . . . . . . . . . .
Character Stripping 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Interrupt Arbitration and IRQN generation 12. . . . . . . . . . . . . . . .
IACKN Cycle, Update CIR 13. . . . . . . . . . . . . . . . . . . . . . . . . .
Polling 13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Enabling and Activating Interrupt sources 13. . . . . . . . . . . . .
Setting Interrupt Priorities 13. . . . . . . . . . . . . . . . . . . . . . . . . .
Modes of Operation 14. . . . . . . . . . . . . . . . . . . . . . . .
Major Modes 14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Minor Modes 15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Watch-dog Timer Time–out Mode 15. . . . . . . . . . . . . . . . . . .
Wake Up Mode 15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Xon/Xoff Operation 18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
REGISTER DEFINITIONS 18. . . . . . . . . . . . . . . . . . . .
MR – Mode Registers 18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
UCIR – Update CIR 13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
General Purpose Output Pin Control 30. . . . . . . .
Register Maps 31. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Register Map Summary 31. . . . . . . . . . . . . . . . . . . . .
Register Map Detail 32. . . . . . . . . . . . . . . . . . . . . . . .
Reset Conditions 41. . . . . . . . . . . . . . . . . . . . . . . . . . .
Device Configuration after Hardware Reset or CRa cmd=x1F 41
Cleared registers: 41. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Clears Modes for: 41. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Disables: 41. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Halts: 41. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Limitations: 41. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DC Electrical Specifications (5V) 42. . . . . . . . . . . .
AC Electrical Characteristic (5V)
43. . . . . . . . . . . .
DC Electrical Specifications (3.3V) 45. . . . . . . . . .
AC Electrical Characteristics (3.3V) 46. . . . . . . . . .
INDEX
52. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DESCRIPTION
The Philips 28L198 Octal UART is a single chip CMOS–LSI
communications device that provides 8 full-duplex asynchronous
channels with significantly deeper 16 byte FIFOs, Automatic
in–band flow control using Xon/Xoff characters defined by the user
and address recognition in the wake up mode. Synchronous bus
interface is used for all communication between host and OCTART.
It is fabricated using Philips 1.0 micron CMOS technology that
combines the benefits of low cost, high density and low power
consumption.
The operating speed of each receiver and transmitter can be
selected independently from one of 22 fixed baud rates, a 16X clock
derived from one of two programmable baud rate counters or one of
three external 16X clocks (1 available at 1x clock rate). The baud
rate generator and counter can operate directly from a crystal or
from seven other external or internal clock inputs. The ability to
independently program the operating speed of the receiver and
transmitter makes the Octal UART particularly attractive for dual
speed full duplex channel applications such as clustered terminal
systems. The receivers and transmitters are buffered with FIFOs of
16 characters to minimize the potential for receiver overrun and to
reduce interrupt overhead. In addition, a handshaking capability and
in–band flow control are provided to disable a remote UART
transmitter when the receiver buffer is full or nearly so.
To minimize interrupt overhead an interrupt arbitration system is
included which reports the context of the interrupting UART via
direct access or through the modification of the interrupt vector. The
context of the interrupt is reported as channel number, type of
device interrupting (receiver COS etc.) and, for transmitters or
receivers, the fill level of the FIFO.
The Octal UART provides a power down mode in which the
oscillator is stopped but the register contents are maintained. This
results in reduced power consumption of several orders of
magnitudes. The Octal UART is fully TTL compatible when
operating from a single +5V power supply. Operation at 3.3 volts is
maintained with CMOS interface levels.
The device also offered in a version which maintains TTL input and
output levels while operating with a 3.3 volt power supply.
