CPU GLU is the general logic unit that performs some of the same functions as the GLUE chip in the Macintosh II-family and SE/30. It incorporates interface functions to system RAM and ROM, SCC, SCSI, VIA, SWIM, and Video peripheral chips. The CPU GLU performs the following functions:
• Decodes addresses to determine which device is being requested by the CPU and asserts the chip select signal
• Generates the 15.6672 MHz clock and generates the clock signals for the SWIM, ASC, and VIA chips
• Monitors data transfers and generates the Bus Error signal to halt the CPU is necessary
• Handles hardware handshaking with the SCSI chip
• Handles the interrupt from the ASC, VIA, or SCC chip
• controlls access to the RAM connector, but does not provide all the address signals for the full 9MB available in the memory map. The chip only routes addresses from $10 0000 to $4F FFFF to this Expansion RAM connector.
