RadiSys EPC - 6A Hardware Reference Manual page 17

EPC-6A Hardware Reference
The EPC-6A performs these major initialization steps:
1. Display
At power-up, this display reads 8. When the system begins the POST (Power On Self
Test), this number changes.
2. Run selftests; display
At various times during the POST, a new code displays in the 7-segment display. For
detailed information about displayed codes, see the POST code description. To see a
list and explanation of these codes, see Chapter 6, Error Messages.
3. Shadow PicoFlash RFA BIOS extension
To access the RFA (Resident Flash Array) as a DOS disk, you must shadow a BIOS
extension that chains the INT13 disk interface. This checkpoint essentially starts a
flash disk driver.
a. Check for catastrophic errors
Any error that prevents the system from reaching INT 19 (which attempts to boot
the OS) halts the system. The 7-segment LED displays the last completed POST
task and the initialization sequence terminates.
If the EPC-6A has a problem that prevents the POST program from running, the
7-segment LED displays the number "8".
b. Check for configuration errors
Errors that do not prevent the system from booting that the CMOS configuration
can correct are considered configuration errors. An example of a configuration
error is an incorrect EXM ID entered for an EXM card.
If the selftest completes successfully, the system is configured using configuration
information maintained by the BIOS in a small battery-backed CMOS RAM.
If a problem is encountered, it causes the BIOS to load MS-DOS from RFA and
then give DOS control. This allows the user to alter the boot process.
MS-DOS always loads from flash, which is a read-write file system. It is
recommended that you embed ABORTSWI.EXE your AUTOEXEC.BAT file to
allow users to alter the machine's boot process. During development, users may
find it convenient to expose the keyboard connector so they can press the F8 key
to step through the CONFIG.SYS and AUTOEXEC.BAT files.
The method for interacting with DOS is described in the next section. Problems at
this point are regarded as non-catastrophic, and include loss of the configuration
information due to a battery failure or change, and a mismatch between the type of
installed EXM versus the type expected.
errors is saved in the upper 2K bytes of the SRAM for use by the setup program.
If there are no errors, the BIOS looks for a boot device with a valid boot image.
The boot device can be the on-board flash memory or a source specified in the
CMOS configuration information (using the setup program) If a boot device is not
present, the BIOS invokes the ROM DOS.
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Information about non-catastrophic