IBM PS/2 Model 9576/9577 Lacuna

Chipset parts: IBM 10G4672 (I/O controller) IBM 71G0438 (System Controller)

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Release date:  Unknown      [see all boards with this chipset]


This chipset is found in the 8576/9577 Lacuna models (i/s). It operates at 25MHz and 33MHz. In addition to the chips, it has the following PALs:

  • IBM 68G3088
  • IBM 95G9659
  • IBM 68G3096
  • IBM 95G9689

There has been no investigation to read these PALs. Their function is unknown.

10G4672 I/O controller

No datasheet exists for this chip. It is found in many later PS/2s. It includes the following functions:

  • Micro Channel interface for internal peripherals (incl. POS)
  • Interrupt controller
  • Timers
  • Keyboard and mouse controller
  • Real time clock (RTC) and CMOS logic control (external)
  • 2x Serial interface
  • 1x Parallel interface
  • 82077 floppy disk controller (FDC) support (external)
  • EEPROM controller (external)

Further Info:

71G0438 System Controller

It implements the following functions:

  • Memory controller
  • I/O (Micro Channel) controller (BIU)
  • DMA controller
  • ECC logic
  • Buffers

Further info:

Drivers: not available
Documentation: not available
Other files: not available