AM186ES Advanced Micro Devices, AM186ES Datasheet - Page 20

• Manufacturer Part Number: AM186ES
• Description: microcontrollers provide a low-cost/ high-performance solution for embedded system designers who wish to use the x86 architecture.
• Manufacturer: Advanced Micro Devices

1.3
Figure 1-3
1.3.1
1.3.2
1-6
APPLICATION CONSIDERATIONS
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.
The nonmultiplexed address bus is available in addition to the 186/188 multiplexed address/
data bus (AD15–AD0). The two buses can operate simultaneously or the AD15–AD0 bus
can be configured to operate only during the data phase of a bus cycle. See the BHE/ADEN
and RFSH2/ADEN pin descriptions in Chapter 3, and see section 5.5.1 on page 5-4 for
additional information regarding the AD15–AD0 address enabling and disabling.
Figure 1-3 illustrates an example system design that uses the integrated peripheral set to
achieve high performance with reduced system cost.
Basic Functional System Design
Clock Generation
The integrated clock generation circuitry of the Am186ES and Am188ES microcontrollers
allows the use of a times-one crystal frequency. The design in Figure 1-3 achieves 40-MHz
CPU operation, while using a 40-MHz crystal.
Memory Interface
The integrated memory controller logic of the Am186ES and Am188ES microcontrollers
provides a direct address bus interface to memory devices. The use of an external address
latch controlled by the address latch enable (ALE) signal is not required.
Individual byte write-enable signals are provided to eliminate the need for external high/
low-byte, write-enable circuitry. The maximum bank size programmable for the memory
PWD Input
Converter
RS-232
40-MHz
Crystal
Level
Features and Performance
Microcontroller
X2
X1
PWD
Serial Port 0
Serial Port 1
Am186ES
AD15–AD0
A19–A0
WHB
WLB
UCS
LCS
RD
Flash PROM
Static RAM
WE
Address
Data
OE
CS
WE
Address
Data
OE
CS
WE
WE