Olivetti M6 540
M6-540 Specifications (More like an HMM section from IBM!)
M6-5xx Refdisk? Probably needs REFSTAMP 

M6-5xx Diags 1/2? They sort of resemble each other... YMMV...
M6-5xx Diags 2/2?

Olivetti Technical documents

ATI 68800 Super VGA (1MB via 4x 256 K x 8 - 80 ns VRAM chips)
NCR53C700-66 SCSI controller
82077SL-1 Floppy disk controller
BT481 Video RAM DAC
ATI-18811 Video programmable clock generator
ICD2027 System programmable clock generator
RTC DS1387 CMOS Real Time Clock
Up to 64MB FPM, 4, 8, and 16MB, 70nS
   SIMMs must be installed in pairs.
   SIMMs of the same pair must have same capacity.
   Different SIMM pairs can be used.

Mad River Module This board is soldered on motherboard and has the following functions:
- Memory control
- CPU memory interface
- DMA control
- MicroChannel control

Galaxy I/O controller. This component integrates the following functions:
- Microchannel interface for internal peripherals
- Interrupt control
- Timer
- Keyboard and mouse control
- Real time clock and CMOS logic control
- Serial (COM1 and COM2) and parallel interface
- 82077 floppy disk controller support
- EPROM control