The complete address map of all adapter resources is listed below. Note that there is a distinction between accessing Borg's registers as a byte versus a word. For example, a byte read of address C0004 clears the "NuBus slot interrupt", while a word read of the same location returns the high byte of the current timer value. This method of operation was used to decrease the number of address inputs required by the NuBus interface ASIC's, and is common to all boards based on these chips. Also note that some registers are at C0xxx, while others are at C8xxxx. Again, this was done to save address inputs.
Address Function
----------- -----------------------------------------------
FE000-FFFFF Declaration ROM (8KB)
. F0000 Write - Place NuBus local bus in "latched reset"
E0000-EFFFF Test ROM (off card, used by manufacturing)
D0000-EFFFF NuBus access via second register set when enabled (Do not
. access)
. C800E Read Byte - Set NMRQ master mode (Do not use)
. C800C Read Byte - Clear NMRQ master mode (Do not use)
. C800A Read Byte - Set Interrupt "Borg" request (Do not use)
. C8008 Read Byte - Clear Interrupt "Borg" request (Do not use)
. C0006 Read Byte - Set NuBus slot Interrupt request (Do not use)
. C0004 Read Byte - Clear NuBus slot Interrupt request (Do not use)
. C0002 Read Byte - Clear Timer Interrupt (Do not use)
. CXXXX Read Byte - Clear "latched reset"
. C800F R/W Byte - DTACK Control Register 1 (07)
. C800D R/W Byte - DTACK Control Register 0
. C800B R/W Byte - Programmable timer low byte
. C8009 R/W Byte - Programmable timer high byte
. C0007 R/W Byte - TMS chipset Addr.Ext.reg.D4-7->AD20-23 (Do not
. use)
. C0005 R/W Byte - TMS chipset Addr.Ext.reg.D0-7->AD24-31 (Do not
. use)
. C0003 R/W Byte - 68000 Addr. Ext. reg. D4-7->AD20-23 (Do not
. use)
. C0001 R/W Byte - 68000 Addr. Ext. reg. D0-7->AD24-31 (Do not
. use)
. C800E Word - undefined (Do not use)
. C800C Word - undefined (Do not use)
. C800A Read Word - XDMA pins (D0-2) last TMx (D6-7)
. C8008 R/W Word - XDMA/Address Decode control byte (Set to 000A)
. C0006 Read Word - Current low byte timer value in low byte
. C0004 Read Word - Current high byte timer value in low byte
. C0002 R/W Word - NuBus Interface Hardware Configuration reg. (Set
. to 0000)
. C0000 Read Word - Interrupt and Slot ID register in low byte (Do
. not use)
A0000-BFFFF NuBus (Unused, do not access)
93000-9FFFF Reserved (Do not use)
82000-92FFF Shared RAM (64 KBytes) (After writing "10" to RRR at 81E00)
81E80-81FFF Reserved (Do not use)
81E00-81E7F Shared Memory Control Registers
60002-81DFF Reserved (Do not use)
. 60001 Borg's Control Register (LED, speed, module reset)
40040-5FFFF Reserved (Do not use)
40000-4003F Burned-In Address PROM
00000-3FFFF Unused
Article Change History:
29 Mar 1995 - Reviewed and updated format.
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