Browse Prior Art Database

Power on Self Test Display Card

IP.com Disclosure Number: IPCOM000105386D
Original Publication Date: 1993-Jul-01
Included in the Prior Art Database: 2005-Mar-19
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Mara, SP: AUTHOR

Abstract

Disclosed is an alternative device to check Power-On Self Test (POST) Error codes. The POST display card could be used to debug any micropro- cessor based circuit board.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 92% of the total text.

Power on Self Test Display Card

      Disclosed is an alternative device to check Power-On Self Test
(POST) Error codes.  The POST display card could be used to debug any
micropro- cessor based circuit board.

      The conventional method of debugging microprocessor based
circuit cards is to send the POST error codes through the I/O port
(i.e., parallel port, Micro Channel*, etc.) and the error codes are
displayed on to LEDs.  If the hardware problem is in the circuit
between the microprocessor and the I/O port, then it is difficult to
check the error codes.  For such problems we need sophisticated
devices, such as micro- processor emulators, to debug the cards.

      A simple and inexpensive way to solve this problem is to design
a circuit board (Figure) which connects to the microprocessor and
display the error codes.  The physical design shown in the Figure
could be plugged into the microprocessor socket.

      The comparator shown in the block diagram will monitor the
address bus for a particular I/O address selected through the
switches.  During POST, the processor sends the error code to the I/O
port, the same data could be latched and simultaneously displayed
onto the LEDs on the debug card.  Since the address and data are
monitored at the processor bus, a minimal working circuit is
sufficient to capture the error codes.

      The switch provided on the error display board could be changed
for different products to match the I/O address....