Specifications

2.3.6 I/O Wait State Option
A timing limitation in the original NEC V 40 microprocessors used in the Little Board/PC
required several wait states to be inserted on all I/O cycles. The NEC V40 microprocessors
now
shipping no longel lequire the wait states. A jumper, W48, controlS whether the walt
states are enabled or disabled, as shown in Table 2-8.
Table 2-1. I/O Wait States
WAIT STATE PINS
Disables Automatic 1/0 Wait Stetes.
Actual nunber of I/O wait
stetes is detef'llli ned by the
1/2
internel wait state generator
(use Ampro's SETWAIT utility)
Enables Automatic I/O Wait States.
Weit states are autalBtically
2/3
inserted on ell 1/0 cycles.
To ensure compatibility with older version of the Little Board/PC, the board is shipped with
automatic
wait states enabled.
Note
If possible, you should reeonfigure jumper W48 to distIbk
the automatic wait states. With automatic wait states
disabled, they can be set to the desired value under soft-
ware control using the SE1W AIT utility.
2.4 PERIPHERAL INTERFACE CONFIGURATION AND CONNECTIONS
This section discusses the interface requirements of the board's external device interface
connectors. Connector pinouts, signal definitions, device characteristics,
and jumpering
information is included.
2.4.1 Utility Connector - J4
A single 10 pin connector (J4) provides four functions: Speaker, System Reset, Power Indica-
tor LED, and
auxiliary power to the PC Expansion Bus connector (J9). The pinout and signal
defmitions
of the Utility Connector are shown in Table 2-9. Note that the power connections
indicated are not required for operation
of the Little Board/PC, and are only used to supply
power
to the pins indicated on the PC Expansion Bus connector.
2-10