Cossey Hardware Interface For Lisa 1.75

To: Rick Meyers From: George Cossey Date: June 22,1983 Subject: Evaluation of .diagnostic's hardware driver requirements. Hardware Interface for Lisa 1.75 me f ollow1ng interfaces are needed, for the diagnostics, from the hardware interface in tne Lisa 1. 75 ROM. overall, all routines that interface to the hardware 1111st have. safety t 1meout s in them to prevent endless hangs. The timeout error 11l1St also be reported to the caner. All oata area usea·oy the Haraware interface, for a scratch pad or to contain oata, rust reside in the Video memory. Tn1~ makes it able to handle a system without any meroory boards ana i~roves a1agnost1c capability, rne ·arivers rust be able to run entirely in viaeo rneroory, without ever using the ma1nmet00ry. There should be a way to reset the hardware 1nterface software/hardware. Unknown cnanges may occur auring a aiagnostic, and· to return to a known state a reset may be · necessary. ·· The timer chip. Timer 1to and 1t1 canoe assumea to be working,. this is one of the first tests done by the Boot ROM. . ·• r1ner ttO - Need a handler for thls t1mer,: allows· rTlll t1ple timeouts to oe set. Allows a previously set' timeout to be q~ryecJ for remaining time ana possibly deletion from tne timer queue. Neea a way to notify user program.that timeout nas expired, flag · resides in user program and rte passes yo~ 1t • s aaaress? · Timer.ill - For Floppy ariver. Timer ll2 - For Speaker ariver. Standard way to tall<: to--tt)e COPS. "This means a way to send data anq receive data . ' ' with a timeout option, to get around a hang conct1tion. Should be a way to talk to the COPS in a non-structured way, 1.e. not expect or send data in only speci fie formats. A structured way to talk to the COPS shOuld al so be available. A change to the current method would b~~ to have a timeout on rrultiple byte data streams. This will allow getting out 1f only part of a roou~e stream comes in, a tirreout error should occur. This would also handle if rultiple data is oeing sent, as in a date, and the COPS stops accepting data. Should be able to use the COPS in a'polled ioode or an interrupt roooe. 11 Need a handler for Speaker values, volUrre and frequency. This latch requires a shadow" to be kept in mennory. Need a handler for Contrast values. This latch requires a "shadow" to oe kept in reroory. · Astandard floppy driver, capable pf handling either the 871 or the Sony, using tne IWM chip. Primitive corrrnands ffLISt be allowed, with error trapping. High level cofTlllands should be available with error trapping. A built-in hard disk driver . ' The special diagnostic co1110ands in the disk drive oust be accessiable. Th1LS driver rust allow low level and hign level corrmands. AProfile hard disk driver, driving out of a parallel interface car.a. This driver rrust allow low level and lnigh level con11lands . standard MMU registier routines, for reading and for writing. Checksums in all ROt1s rrust be in a standard place in the…