Two SEs & Accessories - $300

[jdcurry]

BBU, short for the Bob Bailey Unit, combines a whole lot of functions which were handled by individual chips (PLA's) in earlier Macs.
One of the issues you had before with the display being garbled,, well, the BBU handles memory access for the video, so the sypmtoms make an bit more sense now seeing the state of your BBU!

---edit--- Feeling old, keep on getting beaten
@Phipli definitely types faster

That seems like quite an honor, having it named after an Apple engineer.

"After joining Apple, Bailey consolidated the six Programmable Array Logic (PAL) chips of earlier compact Macs down to two for the Macintosh SE, which was released in 1987. Bailey's custom chip designs were manufactured for Apple by VLSI Technology and General Logic Unit (GLU) and became known as "Bob Bailey Units" (BBUs). Original Macintosh team member Andy Hertzfeld credited Bailey and Brian Howard with engineering the best of the early Macintosh models"

 

[joshc]

... on his phone

@Berenod, here you go :

https://macintoshgarden.org/apps/mavis-beacon-teaches-typing

Now we're talking. That is actually how I learned to type... I loved Mavis Beacon so much.

Back on topic, there are two custom ASICs that were introduced with the SE, the BBU is one of them and the other is the GLU - also designed by Bob Bailey.

A book I find very interesting is Apple's own "Guide to the Macintosh family hardware" which provides technical details of each Macintosh model.

Guide to the Macintosh family hardware : Apple Computer, Inc : Free Download, Borrow, and Streaming : Internet Archive

Macintosh: Guide_to_the_Macintosh_Family_Hardware (Second Edition)

archive.org

BBU custom IC
The BBU is an Apple custom integrated circuit that performs a variety of logic functions in the Macintosh SE computer, as follows:

■ It decodes addresses to determine which device is being requested by the main processor.
■ It asserts the device-select signal to the appropriate device.
■ It generates the RAM address strobes (/RAS and /CAS) and controls the multiplexers (MUXs) that feed addresses to RAM.
■ It controls all video functions, including reading data directly from RAM and shifting it out as a bit stream to the video board.
■ It generates the vertical and horizontal blanking interrupt signals used to coordinate the video circuitry.
■ It controls all sound functions, including reading data from RAM and sending it to the sound IC.
■ It provides a speed-control signal for single-sided floppy disk drives.
■ It generates the 7.8336 MHz clock used by the main processor.
■ It generates the 3.672 MHz clock used by the SCC to control communication rates and by the microprocessor in the ADB transceiver.
■ It monitors data transfers and generates the Bus Error signal to halt the main processor if a transfer fails to complete successfully.
■ It handles hardware handshaking with the SCSI controller, making SCSI transfers faster and more secure than in the Macintosh Plus computer.
■ It asserts the /IPLO interrupt to the main processor when it receives an interrupt request from the VIA or SCSI.
■ It deasserts the /IPLO interrupt to the main processor when the /IPL1 interrupt is asserted by the SCC.

GLU custom IC
The GLU is a programmable logic array IC in the Macintosh SE used to perform some logic functions not included in the BBU. The GLU performs the following tasks:

■ It generates disk drive enable signals that choose between the upper and lower internal floppy disk drives.
■ It controls whether interrupt requests from the SCSI are passed on to the BBU.
■ It inverts the write data (WR) signal to the floppy disk drives.
■ It buffers the 15.6672 MHz master clock used by the BBU and the IWM and provided to the processor-direct slot.
♦ Note: Do not confuse the GLU IC in the Macintosh SE with the GLUE IC in the Macintosh SE/30 and Macintosh II-family computers. The GLUE IC is described in the following section

 

[Phipli]

Now we're talking. That is actually how I learned to type... I loved Mavis Beacon so much.

Same, version 2 on an SE/30 in the late 90s.

 

[PotShotScott]

is there an apple SE ethernet card to rj45 adapter out there? IF I dare try to connect to the internet is it even possible?

I’ve got a card like this in an SE and have used a Mac SSH terminal to use one of my Linux servers online. Never tried a browser - terminal shell is painful enough…