Portserver Bios; Power On Self Test (Post) Sequence - Digi PortServer/8 User Manual

PortServer BIOS

The PortServer' BIOS can be broken down into three parts: Power On Self Test (POST),
Command Mode and user diagnostics.
The POST sequence performs a series of basic tests to ensure that the microprocessor, memory,
network interface controller, etc. are functioning properly. Command Mode is used to activate the
Ethernet operating system and to switch to the user diagnostics. The user diagnostics are used for
more extensive testing of the PortServer hardware.

Power On Self Test (POST) Sequence

The PortServer POST sequence is initiated after the PortServer box is reset or the hardware
watchdog timer expires.
The ten LED indicators on the front panel are lit upon successful completion of each of the ten
tests. If an error occurs, the LED is not lit. All ten LEDs should be lit for one second upon the
completion of the POST sequence, before the firmware begins the optional software download or
enters Command Mode.
The following table lists the tests performed during the POST sequence, and the LED that corre-
sponds to each test.
The front panel alphanumeric display shows "EP" when saving to EEPROM, "b1," "b2," etc.
when booting via TFPT, and "E1," "E2" etc. for TFTP errors.
The configuration is cleared by holding both pushbuttons
"EP" is displayed. (See Resetting the PortServer to Factory Defaults on page 80.)
POST Tests
Far jump from FFFF0h to FFC00h.
Enable upper memory - EPROM (128K).
Set peripheral chip select base address and PCS 0-3.
Enable lower memory - DRAM.
Enable midrange memory base address - DRAM.
Set midrange memory size and PCS 4-6.
Processor flag test.
Processor register test.
Set enhanced mode for the 80186.
Perform LED test.
Clear all LEDs and display PO.
Charge memory cells.
Test 256K DRAM from 00000h to 3FFFFh.
and down during powerup until
LED
TD
RD
PortServer Terminal Server Ÿ Page 71