User manual

ATHENA CPU User Manual V1.40 Page 28
6.4 Flash Memory
Athena contains a 2Mbyte 16-bit wide flash memory chip for storage of BIOS and other system
configuration data.
6.5 Backup Battery
Athena contains an integrated RTC / CMOS RAM backup battery. The battery is located adjacent
to the PC/104 bus connector J1 (within the PC/104 outline). This battery has a capacity of
120mAH and will last over 3 years in power-off state. The on-board battery is activated for the
first time during initial factory configuration and test. Note that storage temperature of the board
can affect the total battery life. Storage at 23ºC is recommended.
6.6 System Reset
Athena contains a chip to control system reset operation. Reset will occur under the following
conditions:
♦ User causes reset with a ground contact on the Reset input
♦ Input voltage drops below 4.75V
♦ Over current condition on output power line
The ISA Reset signal is an active high pulse with a duration of 200ms. The internal PCI Reset is
active low, with a pulse width duration of 200 msec typical.
6.7 On-Board Video
The on-board video for the Athena board is based on an S3-TwisterT (VIA 8606 “PN133T”
Northbridge) video system. As such, the board memory is shared between the Video and main
system memory. A block of memory is configured (via BIOS Settings, accessible in the BIOS
configuration menus) for video which is then removed from use for main system memory. This
implies that the more memory used for the Video, the less memory is available for system
resources.
Note that the video memory can be set at 8Mbytes for almost all applications – increasing the
memory size will not increase video performance. Additional memory will only benefit the limited
3D support provided by the chipset. Also note that 3D hardware acceleration is not supported
across extended temperature range. In general, this 3D hardware is typically only used for 3D
games – most likely, these limitations will not affect most embedded applications.
Note that the low-level BIOS can support LCD output in conjunction with standard RGB output
(i.e., dual-displays).