AMD

P R E L I M I N A R Y

2

Am186EM and Am188EM Microcontrollers

Am186EM MICROCONTROLLER BLOCK DIAGRAM

S2–S0

Interrupt

Control Unit

Timer Control

Unit

DMA

Unit

Bus

Interface

Unit

Execution

Unit

Chip-Select

Unit

Clock and

Power

Management

Unit

Control

Registers

16-Bit Count

Registers

Max Count A

Registers

16-Bit Count

Registers

20-Bit Destination

Pointers

20-Bit Source

Pointers

Control

Registers

Control

Registers

Control

Registers

0

1 (WDT)

2

0

1

Max Count B

Registers

Refresh

Control

Unit

Control

Registers

Control

Registers

Control

Registers

CLKOUTB

CLKOUTA

INT4

INT3/INTA1/IRQ

INT2/INTA0

INT1/SELECT

INT0

TMROUT0

TMROUT1

DRQ0

DRQ1

GND

TMRIN0

TMRIN1

ARDY

SRDY

DT/R

DEN

HOLD

HLDA

Asynchronous

Serial Port

Synchronous Serial

Interface

TXD

RXD

SCLK

SDATA

SDEN0 SDEN1

NMI

A19–A0

AD15–AD0

ALE

BHE/ADEN

WR

WLB

WHB

RD

RES

LCS/ONCE0

MCS2–MCS0

PCS6/A2

PCS3–PCS0

PCS5/A1

UCS/ONCE1

X2

X1

Control

Registers

PSRAM

Control

Unit

MCS3/RFSH

PIO

Unit

PIO31–

PIO0*

Note:

* All PIO signals are shared with other physical pins. See the pin descriptions beginning on page 24 and Table 2

on page 28 for information on shared function.

S6/

UZI

CLKDIV2