© 2005 Ubicom, Inc. All rights reserved.
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UbicomTM and the Ubicom logo are trademarks of Ubicom, Inc.
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CTM is a trademark of Philips Corporation
All other trademarks mentioned in this document are property of their respec-
tive companies.
March 1, 2005
SX20AC/SX28AC
Configurable Communications Controllers with EE/Flash Program
Memory, In-System Programming Capability and On-Chip Debug
1.0 PRODUCT OVERVIEW
1.1 Introduction
The Ubicom SX family of configurable communications
controllers are fabricated in an advanced CMOS process
technology. The advanced process, combined with a
RISC-based architecture, allows high-speed computa-
tion, flexible I/O control, and efficient data manipulation.
Throughput is enhanced by operating the device at fre-
quencies up to 75 MHz and by optimizing the instruction
set to include mostly single-cycle instructions. In addition,
the SX architecture is deterministic and totally reprogra-
mable. The unique combination of these characteristics
enables the device to implement hard real-time functions
as software modules (Virtual PeripheralTM) to replace tra-
ditional hardware functions.
On-chip functions include a general-purpose 8-bit timer
with prescaler, an analog comparator, a brown-out detec-
tor, a watchdog timer, a power-save mode with multi-
source wakeup capability, an internal R/C oscillator, user-
selectable clock modes, and high-current outputs.
Figure 1-1. Block Diagram
Interrupt
MIWU
Port B
Comp
Power-On
Reset
RESET
8-bit Watchdog
Timer (WDT)
8-bit Timer
RTCC
8
8
8
Port C
8
8
Port A
8
4
Internal Data Bus
In-System
Debugging
In-System
Programming
2k Words
EEPROM
System
Clock
Brown-Out
MIWU
MCLR
OSC
Driver
4MHz
Internal
RC OSC
Clock
Select
÷ 4 or ÷ 1
136 Bytes
SRAM
Address
Write Data
Read Data
Instruction
W
FSR
STATUS
PC
MODE
OPTION
System Clock
OSC1 OSC2
Fetch
8
8
12
Address
12
8
8
8
8
ALU
8
8
8
3
RTCC
Analog
8
Interrupt Stack
PC
3 Level
Decode
Executive
Write Back
IREAD
Stack
Instruction
Pipeline
Prescaler for RTCC
or
Prescaler for WDT