System Support Functions - American Megatrends Baby Screamer LC User Manual

S y s t e m S u p p o r t F u n c t i o n s S y s t e m S u p p o r t F u n c t i o n s
The Baby Screamer LC motherboard has the following standard AT-compatible system elements:
• seven Direct Memory Access (DMA) channels,
· Channels 0 - 3 for 8-bit data transfer, and
· channels 5 - 7 for 16-bit data transfers.
• sixteen interrupt levels,
Supports eleven levels of interrupt:
IRQ3 - IRQ7, IRQ9 - IRQ12, IRQ14, and IRQ15.
• three programmable timers,
• a system clock,
• standard I/O capability, including:
· uses 32-, 16-, and 8-bit memory devices, and
· uses 16- and 8-bit I/O devices.
• I/O bus operating at 8 MHz.
• 8- and 16-bit IBM AT-compatible expansion slots,
• the standard I/O address space of 100h through 3FFh,
• 24-bit memory addresses to access 16 MB of memory,
• uses the I/O channel check to generate an NMI,
• has I/O wait state generation,
• has an open bus structure (allowing multiple microprocessors to share the system's resources, including memory),
• allows system memory refresh from channel microprocessors,
• has a crystal-controlled real time clock with battery back-up,
• provides a standard 5-pin IBM AT-compatible DIN connector for the keyboard,
• supports a hardware Deturbo switch,
• has a keyboard lock to prevent unauthorized access, and
• has a standard speaker attachment.
Chapter 1 - Introduction
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