Parent

Supersoft/Landmark Diagnostic ROM for 16KB-64KB version of IBM 5150 motherboard



WARNING: If your 16KB-64KB motherboard has a RAM related problem, the Supersoft/Landmark Diagnostic ROM is known to display incorrect and misleading information.
It is though the Supersoft/Landmark Diagnostic ROM is not intended for the 16KB-64KB version of IBM 5150 motherboard.
Click here for a list of known bugs.


Four RAM banks of 16 KB each.

Bank 0: 16 KB,  starting at address 0
Bank 1: 16 KB,  starting at address 4000 hex  (16K)
Bank 2: 16 KB,  starting at address 8000 hex  (32K)
Bank 3: 16 KB,  starting at address C000 hex  (48K)


On an IBM 5150 motherboard, socket U33 is where the Supersoft/Landmark ROM needs to be placed.

To use a 27xxx series EPROM (e.g. 2764/27128/27256/27512) in socket U33, you will require a suitable adapter (adapter details).

U33 image for a 2764 EPROM (or 27C64) in a MK36000/2764 adapter ( or in 2364/2764 adapter, such as the one at here )
U33 image for a 27128 EPROM (or 27C128) in a MK36000/27128 adapter ( or in 2364/27128 adapter, such as the one at here )
U33 image for a 27256 EPROM (or 27C256) in a MK36000/27256 adapter ( or in 2364/27256 adapter, such as the one at here )
U33 image for a 27512 EPROM (or 27C512) in a MK36000/27512 adapter ( or in 2364/27512 adapter, such as the one at here )



Important Notes:

• Read the earlier warning about RAM related bugs.
• Some video cards will not work with this PC (and XT) version of the Supersoft/Landmark ROM.

- My IBM MDA card works.
- My IBM CGA card works.
- My IBM EGA card will display, but poorly.

- My unbranded clone MDA card works.
- My unbranded clone CGA card works.

- None of my VGA cards work.  More information here.

• The SYSTEM MEMORY TO 10000  test will fail if 64 KB (10000 hex = 64K) of RAM is not fitted.
So, that is 64 KB on the motherboard (all four RAM banks populated).
RAM related switches on the motherboard are ignored (switches SW1:3 and SW1:4, and SW2).
• The KEYBOARD CONTROLLER  test will fail if no PC-class keyboard is connected to the 5150 motherboard.
• The FLOPPY CONTROLLER  test requires that a floppy controller card is fitted to the 5150 motherboard.  For this test, the card does not need any drives connected to it.
• The NONMASKABLE INTERRUPT  test will fail if the math coprocessor (8087) is absent and you have switch 2 on SW1 in the wrong position for that (off).
• The U28 ROM  test is expected to fail, because there is nothing in the U28 socket.


Minor Notes:

• It is observed that when a test fails, the Supersoft/Landmark ROM switches the motherboard relay on/off three times.  (The clicks are very audible.)
• The settings of the switches within SW1 on the 5150 motherboard are ignored, except for switch 2.
• The settings of the switches within SW2 on the 5150 motherboard are ignored.
• Switches 3 and 4 within SW1 on the IBM 5150 motherboard do not enable/disable RAM banks.  The 4 motherboard banks are always enabled.  That is why in the IBM 5150, all motherboard RAM banks must be populated before RAM is added via expansion card/s.
• Ignore the box labelled, "XT SW1".  That is for when the ROM is used in an IBM 5160 (IBM XT).
• The term 'KEYBOARD CONTROLLER' is misleading.  Unlike the IBM 5170, the IBM 5150 does not have a keyboard controller chip.  Discrete components are used instead.
• There is nothing in the manual that indicates that codes are sent to port 80h.
• An example output is shown at here.