rtd DM5816, User Manual

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DM5816/DM6816 RTD Embedded Technologies, Inc.
8
Introduction
The DM5816/DM6816 Pulse Width Modulator (PWM) dataModule
®
turns your IBM PC-compatible
cpuModule™ or other PC/104 computer into a high-performance control system. The DM5816 and
DM6816 are the same board except for the addition of the AT bus connector on the DM6816. This
connector allows you to stack the module easily with other AT modules and also allows you access to
the AT interrupts. Through the rest of this manual, the module will be referred to as the DM5816. Ultra-
compact for embedded and portable applications, the module features:
• Nine 8-bit Pulse Width Modulated Outputs with trigger input
• Three 16-bit timer/counters and on-board 8 MHz clock,
• Operation from 5V supply,
• DOS example programs with source code in BASIC and C,
• Diagnostics software.
The following paragraphs briefly describe the major functions of the module. A detailed discussion of
module functions is included in subsequent chapters.
Pulse Width Modulators (PWM)
The DM5816 has nine 8-bit pulse width modulator circuits. The PWM function is divided into three blocks
with each having three PWMs with trigger inputs.
Each block consists of an 8-bit counter that is driven by either an on-board 8 MHz clock, the 8 MHz
clock divided by a 16-bit counter/timer or an external clock. There are three 8-bit PWM registers. The
counter output is compared to each register and the PWM outputs are high if the count is less than the
register and low if the count is greater than the register. The trigger input can be used to generate very
low duty cycle signals while retaining the 8-bit PWM resolution.
8254 Timer/Counters
An 8254 programmable interval timer provides three 16-bit, 8 MHz timer/counters to support a wide range of
user timing and counting functions.
What Comes With Your Module
You receive the following items in your module package:
•
DM5816 module with stack-through bus header
•
Mounting hardware
• Example programs in BASIC and C with source code & diagnostics software
•
User’s manual