
Features and Performance
1-6
1.3
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.
Figure 1-3
Basic Functional System Design
1.3.1
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.
1.3.2
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
X2
X1
RS-232
Level
Converter
Serial Port 0
LCS
UCS
WHB
WLB
WE
Address
Data
OE
CS
WE
RD
WE
Address
Data
OE
CS
WE
AD15–AD0
A19–A0
Flash PROM
Static RAM
Am186ES
Microcontroller
40-MHz
Crystal
Serial Port 1
PWD
PWD Input
Содержание Am186 ES
Страница 1: ...Am186 ES and Am188 ES User s Manual...
Страница 4: ...iv...
Страница 12: ...Table of Contents xii...
Страница 22: ...Features and Performance 1 8...
Страница 60: ...System Overview 3 28...
Страница 84: ...Chip Select Unit 5 14...
Страница 132: ...Timer Control Unit 8 8...
Страница 166: ...Programmable I O Pins 11 6...
Страница 184: ...Register Summary A 18...