Little Board/P5x Technical Manual
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be stacked directly on top of the Little Board/P5x using its PC/104-Plus expansion bus interface as a
rugged and reliable interconnect.
The Little Board/P5x module’s on-board EIDE, video interfaces, and optional SCSI interface are
internally connected to its PCI bus. In addition, you can attach PCI per iphe rals to the board ’s
stackable PCI bus expansion connector in much the same way PC/104 modules are stacked on the
PC/104 connectors. The PCI expansion connector consists of 4 rows of 30 pins (120-pin heade r), and
carries all of the appropriate PCI signals to accommodate up to 4 PCI add-on modules. The bus
operates at clock speeds up to 33 MHz.
Compact Flash Disk
The Compact Flash interface allows you to substitute solid-state Flash me mory for a conv entio nal
rotating-media drive. Any DOS-based application, including the ope rating sy stem, u tilities, driv ers,
and application programs, can easily be run from the Compact Flash device without modification
The Compact Flash disk is a solid-state disk system that emulates an IDE drive. It uses standard
Compact Flash disk media, similar to a PCMCIA memory card, but smaller. Insert the Compact
Flash disk media in the on-board Compact Flash socket, and use it in much the same way you
would use a removable-media hard drive. The Compact Flash drive is architecturally equivalent to
an IDE drive in your system. When installed, it becomes one of the two IDE drives supported by the
primary EIDE disk controller. It can be configured as either an IDE master or slave drive.
Serial Ports
The Little Board/P5x provides four PC-compatible RS-232C serial ports, implemented using
16C550-type UARTs. These UARTs are equipped with 16-byte FIFO buffers to improv e thro ughp ut.
Serial 1 through Serial 4 are configured for RS-232 operation and are compliant with standard PC
serial port specifications. The ports’ RS-232 level shifters incorporate built-in vo ltage pu mps to
generate RS-232 voltage levels from the system +5V supply.
You can optionally configure Serial 1 for RS-485 operation. In addition, Serial 2 and Se rial 4
provide connections for TTL-level serial signals.
Parallel Port
An enhanced bi-directional parallel port interface conforms to the IEEE-1284 standard. It provides
features attractive to embedded system designers, including increased speed, an internal FIFO
buffer, and DMA transfer capability.
Floppy Interface
An on-board floppy disk interface provides access to standard floppy drives. The interface supports
up to two floppy drives, 5.25 inch or 3.5 inch, in any combination. All standard floppy d rive ty pes,
from 360K 5.25 inch to 1.44M 3.5 inch are supported.
PCI-Bus EIDE Interfaces
On-board PCI EIDE/Ultra DMA/33 interfaces provide high-speed hard disk, IDE CD-ROM drive,
and other IDE device access. The interfaces support up to four IDE devices (via primary and
secondary drive interfaces). The interfaces are fully compliant with the AS/NSIS ATA Rev. 3.0