Sun Microsystems 60 service manual Diskette Port

					Parallel port
						DB-25
				EMI
	Parallel
	port			filter
Cheerio	SuperIO		Keyboard
		1		EMI
	Serial
ASIC
	port	2	Mouse	filter
Diskette drive					Keyboard
					& mouse
Mode select
Density sense						DIN-8

	Diskette drive
EBus	edge connector
	Diskette
	controller

FIGURE C-6Keyboard and Mouse, Diskette, and Parallel Port

Functional Block Diagram

C.1.10.2 Diskette Port

The diskette port is supported by a diskette controller, located on the SuperIO ASIC, and the Cheerio ASIC. The diskette controller is software compatible with the DP8473, DP765A, and the N82077 diskette controller. The SuperIO ASIC is compatible with perpendicular recording drives (2.88-Mbyte formatted diskettes) as well as standard diskette drives. There is a 16-byte FIFO for buffering and support for burst and non-burst modes. The diskette controller handles data rates of 2 Mbps, 1 Mbps, 500 Kbps, and 250 Kbps.

Note –Sun utilizes the N82077 diskette controller.

There are two extra pins on the Cheerio ASIC that combine with the SuperIO component-to-diskette drive interface to support all Sun standard diskette drives. This includes diskette drives that use Density_Select and Density_Sense pins as well as diskette drives that use a Disk_Change signal. It is DMA driven via a DMA channel in the EBus interface of the Cheerio ASIC. Auto eject and manual eject diskette drives (IDs of 0 or 1, respectively) are supported.

C-20Sun Ultra 60 Service Manual • August 2001