• Tandon Type A AT 29 Feb 1988 BIOS Post Codes
  • Tandon Type B AT 1992 BIOS Post Codes
  • Tandon 486 EISA 1989 BIOS Post Codes

 

Tandon Type A AT 29 Feb 1988 BIOS Post Codes:

 01   Test 80286 CPU flags and registers 
 02   Test BIOS ROM checksum 
 03   Test MC 146818 CMOS RAM battery - real time clock 
 04   Test 8254 programmable interrupt controller 
 05   8254 programmable interrupt controller test failed 
 06   Initialize RAM refresh 
 07   Test first 16K RAM 
 08   Initialize cold boot interrupt vectors 
 09   Test 8259 programmable interrupt controller and interrupt vectors 
 0A   Fill in temporary interrupt vectors 
 0B   Initialize interrupt vector table 1 
 0C   Initialize interrupt vector table 2 
 0D   Initialize fixed disk vector 
 0E   Interrupt vector test failed 
 0F   Clear keyboard controller input buffer 
 10   Keyboard controller input buffer clearing failed 
 11   Run keyboard controller self test 
 12   Initialize equipment check data area 
 13   Determine presence of and install 80287 math coprocessor 
 14   Test MC 146818 CMOS RAM disk value range 
 15   Test for and install parallel port 
 16   Test for and install serial port 
 17   Call interrupt 19 boot loader 

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Tandon Type B AT 1992 BIOS Post Codes:

 01   Cold boot started 
 06   Initialize chipset if any 
 07   Warm boot entry; Start of 8042 keyboard controller self test 
 08   Part of cold boot keyboard initialization passed 
 09   Keyboard self test passed; Test CMOS checksum 
 0A   Test CMOS RAM battery 
 0B   Save CMOS RAM battery condition in CMOS diagnostic/status register 
 0C   Finished saving CMOS RAM battery condition 
 0D   Test 8254 programmable interrupt timer; Disable RAM parity, I/O parity, DMA controllers and system speaker; Enable timer channel 2 
 0E   8254 programmable interrupt timer test failed, xx is the failing channel number 
 0F   Initialize 8254 programmable interrupt timer channels; Conduct memory refresh test 
 10   Refresh test failed 
 11   Test base 64K RAM and fill with zeros 
 12   64K RAM test failed - 3 long beeps and system halt 
 13   64K RAM test passed 
 14   Set up stack; Disable mappers for systems that support EMS drivers; Initialize battery beep flag parameters for notebook; Perform read/write test of CMOS RAM; Enable error message if failed 
 15   CMOS RAM read/write test complete 
 16   Calculating CPU speed; May set to low if CMOS RAM failed 
 18   Test and initialize both 8259 programmable interrupt controllers 
 1A   8259 programmable interrupt controllers initialization complete 
 1B   Install interrupt handler and vector for interrupt 0F to check for unexpected interrupts; Halt is unexpected interrupt occurs 
 1C   Unexpected interrupt did not occur; Test 8254 programmable interrupt timer channel 0, IRQ 0 and software interrupt 8 tests 
 1D   Error; Timer 0 interrupt did not occur when expected, system is halted 
 1E   Both 8259 programmable interrupt controllers passed the tests 
 20   Set up interrupt vectors 02-1F 
 21   Set up interrupt vectors 70-77 
 22   Clear interrupt vectors for 41 and 46 
 23   Read 8042 keyboard controller self test result; DMA page register channel 2 
 24   Test for proper 8042 keyboard controller self test result 
 25   Error; Keyboard controller self test failed; System id halted with message displayed 
 26   Keyboard controller self test passed 
 27   Confirm DMA working; Prepare DMA channel 2 for floppy data transfer 
 28   Reinitialize video 
 29   Reinitialize video with cursor off 
 2A   Video parameters are initialized 
 2B   Enable NMI and I/O channel check; Disable 8254 programmable interrupt timer channel 2 and speaker 
 2C   Run RAM test to determine size of RAM 
 2D   RAM sizing complete 
 2E   Send reset command to keyboard controller to initialize a keyboard scan cycle 
 2F   Keyboard has been initialized; Initialize CMOS real time clock 
 30   CMOS real time clock has been initialized; Initialize on board floppy if any 
 31   Install the hard disk controller 
 32   Disk controller has been initialized; Prepare DMA channel 2 for floppy transfers 
 33   Perform equipment check and initialize math coprocessor 
 34   Install the serial and parallel ports 
 35   Test CMOS RAM battery 
 36   Check for keystroke 
 37   Enable 8254 programmable interrupt timer channel 0 for system tick; Enable keyboard and slave interrupt controller 8259 programmable interrupt controller 2 
 38   Timer tick, keyboard and 8259 programmable interrupt controller 2 have been initialized; Enable/disable cache through CMOS RAM 
 39   Enable keyboard interface and interrupts; Go to built in setup program as necessary; Shadow ROM's found 
 3A   Set up complete 
 3B   Test the hard disk and floppy disk 
 3C   Scan for and invoke the adapter ROM's in C800-E000 
 3D   Turn of gate A20; Restore vectors 3bh-3fh with temporary interrupt service routines 
 3E   Gate A20 turned on 
 3F   Call interrupt 19 boot loader 

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Tandon 486 EISA 1989 BIOS Post Codes:

 01   Disable cache, enable ROM, high speed on, turn off cache's, disable EISA NMI's, set master/slave IRQ's to edge triggered, disable reset chaining; Disable 82C601 chip 
 05   Initialize address decoder, 640K RAM; Set BIOS as cacheable, enable extended memory 
 06   Clear shutdown flag 
 07   8042 keyboard controller test; Wait till 8042 buffer empty; Disable 8042 command, read 8042 output buffer; Set response ok to DMA page register channel 2 
 08   Send 8042 keyboard controller NOP command; Get 8042 self test result; Send DMA page register channel 2; If xx=55, then self test ok 
 09   Test BIOS ROM checksum 
 0A   Read CMOS registers 3 times to clear pending CMOS real time clock interrupts; Disable real time clock interrupts; Check battery 
 0B   Bad CMOS RAM battery 
 0C   Send command to port 61 to disable parity and speaker 
 0D   Test 8254programmable interrupt timer counter 
 0E   One of the counter timers is bad; xx indicates the bad counter 
 0F   Enable and check memory refresh 
 10   Memory refresh failed 
 11   Check and clear the first 64K RAM in real mode; Disable NMI; Clear parity latches; Fill 64K with 5555 and check it, then AAA and check it, then 0000 
 12   First 64K RAM memory test failed 
 13   First 64K RAM memory test passed 
 14   Reset the warm boot flag and test CMOS RAM; Turn off caches; Shadow the BIOS; set high speed; Calculate high speed and initialize GP flag; Set low speed and turn off cache if CMOS not good or CMOS speed not high 
 16   Check shutdown flag 123x 
 17   Reset was cold boot 
 18   Prepare 8259 programmable interrupt controllers 
 19   8259 programmable interrupt controllers initialization failed; Initialize video and display the error message 
 1A   Test 8259 programmable interrupt controller 
 1B   Set interrupt 0F to unexpected interrupt vector; Enable timer and interrupt 
 1C   Set interrupt 08 to timer 0 interrupt vector 
 1D   Timer interrupt did not occur; Initialize video and display error message 
 1E   Initialize interrupt vectors 
 1F   Initialize interrupt vectors 00-6F to temporary interrupt service routines 
 20   Set vectors for interrupt 02-1F 
 21   Set interrupt vectors for 70-77, clear vectors 60-67 and 78-FF 
 22   Clear interrupt vectors for 41 and 46 
 23   Read 8042 keyboard controller self test results from DMA page register channel 2 
 24   Test for proper 8042 keyboard controller self test result 
 25   8042 keyboard controller self test failed 
 26   Initialize 8042 keyboard controller 
 27   Check shutdown flag=123x; If no=cold boot 
 28   If cold boot or CMOS RAM is bad, then install video ROM and initialize video; Initialize equipment flags according to primary video adapter and CMOS RAM content; Initialize POST status 
 29   If not cold boot and CMOS RAM ok; Install video ROM and initialize video for mono/CGA; Initialize equipment flags according to primary video adapter and CMOS RAM contents 
 2A   Check for bad CMOS RAM 
 2B   Check shutdown flag=123x 
 2C   If cold boot; Turn off caches; Test memory for size and reinitialize cache status 
 2D   Turn off "POST fail" CMOS RAM bit and display and error messages; Initialize keyboard RAM 
 2E   Initialize 8042 keyboard controller and test keyboard 
 2F   Initialize time of day in real time clock 
 30   Test for and install floppy drive controller 
 31   Enable 82C601 IDE interface; Test for and install hard disk 
 32   Test 8259 programmable interrupt controller DMA registers with 55 then AA, then initialize them to 00 
 33   Test for and initialize math coprocessor 
 34   Test for and initialize parallel and serial ports 
 35   Initialize RAM variables for bad CMOS time, date, checksum and battery 
 36   Wait for user to press Esc or Space; Check for keyboard lock; Clear keyboard lock override; Beep to indicate speed; Display error messages 
 37   Enable system clock tick (IRQ 0); Enable keyboard (IRQ 1); Enable slave interrupt controller (IRQ 2) 
 38   Initialize RAM variables for Ctrl-Alt_Esc 
 39   Enter setup is keystroke pressed 
 3A   Clear screen and update equipment flags according to CMOS RAM contents; Shadow ROM's; Enable/disable cache through CMOS RAM 
 3B   Initialize floppy and hard drives 
 3C   Set POST failed bit in CMOS RAM; Scan for and initialize adapter ROM's 
 3D   Clear the shutdown flag to 0; Disable gate A20 and enable memory wrap in real mode 
 3E   Set vectors for interrupts 3B-3F; Clear post fail bit in CMOS RAM 
 3F   Call interrupt 19 boot loader