AM186 Datasheet, PDF (15/112 Pages) Advanced Micro Devices – High-Performance, 80C186- and 80C188-Compatible, 16-Bit Embedded Microcontrollers with RAM

Direct Memory Interface Example
Figure 1 illustrates the direct interface to memory of the
Am186ER microcontroller. The A19–A0 bus connects
to the memory address inputs, the AD bus connects to
the data inputs and outputs, and the chip selects con-
nect to the memory chip-select inputs.
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.
12.5-MHz
Crystal
Am186ER
Microcontroller
X2
WR
A19–A0
X1 _{AD15–AD0}
RD
UCS
32 Kbyte
SRAM
Am29F400
Flash
WE
Address
Data
OE
CS
COMPARISON OF THE Am186™ER AND
80C186 MICROCONTROLLERS
Serial Port
Timer 0–2
INT4–INT0
Figure 1 shows an example system using a 50-MHz
Am186ER microcontroller. Figure 2 shows a compara-
ble system implementation with an 80C186 microcon-
RS-232
Level
Converter
TXD
RXD
DMA 0–1
CLKOUTA
50 MHz
troller. Because of its superior integration, the
Am186ER system does not require the support devices
required on the 80C186 example system. In addition,
the Am186ER microcontroller provides significantly
better performance with its 50-MHz clock rate.
Figure 1. Am186™ER 50-MHz Example
System Design
T _40-MHz
D ^{R A F Crystal}
X2
BHE
A0
X1
WR
ALE
AD15–AD0
RD
UCS
LCS
PCS0
Timer 0–2
Am29F400
Flash
WE
Address
Data
OE
CS
LATCH
PIOs
Serial
Port
SRAM
WE
WE
Address
Data
OE
CS
RS-232
Level
Converter
INT3
INT2–INT0
DMA 0–1
CLKOUT
20 MHz
Figure 2. Typical 80C186 System Design
Am186^TMER and Am188^TMER Microcontrollers Data Sheet
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