P R E L I M I N A R Y
shown in Figure 1 achieves 40-MHz CPU operation,
KEY FEATURES AND BENEFITS
while using a 40-MHz crystal.
The Am186ES and Am188ES microcontrollers extend
the AMD family of microcontrollers based on the
industry-standard x86 architecture. The Am186ES and
Am188ES microcontrollers are higher-performance,
more integrated versions of the 80C186/188
microprocessors, offering an attractive migration path.
In addition, the Am186ES and Am188ES
microcontrollers offer application-specific features that
can enhance the system functionality of the Am186EM
and Am188EM microcontrollers. Upgrading to the
Am186ES and Am188ES microcontrollers is an
attractive solution for several reasons:
Memory Interface
The integrated memory controller logic of the
Am186ES and Am188ES microcontrollers provides a
direct address bus interface to memory devices. It is
not necessary to use an external address latch
controlled by the address latch enable (ALE) signal.
Individual byte-write-enable signals eliminate the need
for external high/low byte-write-enable circuitry. The
maximum bank size that is programmable for the
memory chip-select signals has been increased to
facilitate the use of high-density memory devices.
n Minimized total system cost—New peripherals
and on-chip system interface logic on the Am186ES
and Am188ES microcontrollers reduce the cost of
existing 80C186/188 designs.
The improved memory timing specifications for the
Am186ES and Am188ES microcontrollers allow no-
wait-state operation with 70-ns memory access times
at a 40-MHz CPU clock speed. This reduces overall
system cost significantly by allowing the use of a more
commonly available memory speed and technology.
n x86 software compatibility—80C186/188-com-
patible and upward-compatible with the other mem-
bers of the AMD E86 family. The x86 architecture is
the most widely used and supported computer ar-
chitecture in the world.
Figure 1 also shows an implementation of an RS-232
console or modem communications port. The RS-232-
to-CMOS voltage-level converter is required for the
electrical interface with the external device.
n Enhanced performance—The Am186ES and
Am188ES microcontrollers increase the perfor-
mance of 80C186/188 systems, and the nonmulti-
plexed address bus offers faster, unbuffered access
to memory.
Am186ES
Microcontroller
Flash PROM
n Enhanced functionality—The new and enhanced
on-chip peripherals of the Am186ES and Am188ES
microcontrollers include two asynchronous serial
ports, 32 PIOs, a watchdog timer, additional inter-
rupt pins, a pulse width demodulation option, DMA
directly to and from the serial ports, 8-bit and 16-bit
static bus sizing, a PSRAM controller, a 16-bit reset
configuration register, and enhanced chip-select
functionality.
X2
WHB
WE
WE
WLB
X1
A19–A0
40-MHz
Crystal
Address
Data
OE
AD15–AD0
RD
CS
UCS
Static RAM
PWD Input
Application Considerations
PW
WE
WE
The integration enhancements of the Am186ES and
Am188ES microcontrollers provide a high-
performance, low-system-cost solution for 16-bit
embedded microcontroller designs. The
nonmultiplexed address bus eliminates the need for
system-support logic to interface memory devices,
while the multiplexed address/data bus maintains the
value of previously engineered, customer-specific
peripherals and circuits within the upgraded design.
Address
RS-232
Level
Converter
Serial Port 0
Serial Port 1
Data
OE
LCS
CS
Figure 1. Am186ES Microcontroller Example
System Design
Figure 1 illustrates an example system design that
uses the integrated peripheral set to achieve high
performance with reduced system cost.
Direct Memory Interface Example
Clock Generation
Figure 1 illustrates the Am186ES microcontroller’s
direct memory interface. The processor A19–A0 bus
connects to the memory address inputs, the AD bus
The integrated clock generation circuitry of the
Am186ES and Am188ES microcontrollers allows the
use of a times-one crystal frequency. The design
10
Am186/188ES and Am186/188ESLV Microcontrollers
AMD [ AMD ]
