Specifications

Hardware Configuration
2–30
The external battery power is combined with the internal battery using low forward voltage drop
Schottky diodes. The 165 milliamp-hour battery provides sufficient current for the onboard real-time
clock for a 10 year life, but if you are going to battery-back-up a device in S0, Ampro recommends a
larger battery, connected through the utility connector.
Note
Some byte-wide devices draw battery backup current through
their chip select lines when power is off. When using memory
devices that do not require battery backup power, remove the
jumper on W2 and set W21 to 2/3. This prevents the backup
battery from being drained prematurely.
SRAM
Typical Devices Pins Jumper Diagram
32K SRAM 43256
128K SRAM 628128
32K NOVRAM Dallas DS1235Y
Benchmarq BQ4013Y
28
32
512K SRAM 628512
512K NOVRAM Dallas DS1650Y
Benchmarq BQ4015Y
32
NOTE: W2 and W21 are show configured for NOVRAMs. To configure W2 and W21
for SRAM battery backup (on S0), install a jumper on W2 and move the jumper on W21
to 1/2. See text for details.
Figure 2-11 SRAM and NOVRAM Jumpering for S0 and S1
2.12 FLAT PANEL/CRT VIDEO CONTROLLER
The Little Board/486i provides an integrated high-performance super VGA video controller. The
video controller supports both CRT and flat panel displays. It uses four connectors to interface with
external devices. These connectors are summarized in the table below. Complete hardware details
about each connector and the features they support are provided in sections that follow.