Cossey Lisa 1.75 Diagnostic Tests

Edit date: 07/27/83 G.Cossey Lisa 1.75 Diagnostic tests. This docunent contains a sirrple description of the diagnostics perforrred by the Lisa 1. 75 Diagnostic packages. · · fDI Checksun test. These tests are done~ ln the Boot ROM and are· to ver1 fy that the correct data was progranmed into eacn1 ROM and that each ROM location is readable. This test calculates the checksum of each ROM, using the sarne method as the Lisa 1. o Boot RON,, and verifies that ectch ROH is correct. 1. For RON ltl. This ROM is the'one tnat contains the Startup and Diagnostic code. If this ROM is bad then a Boot ROM fatal error will occur right away. 2. For ROH #2. This ROH contains :nardware drivers and o. s. routines. If this ROH is bad then a fatal error will. occur after an other diagnosqcs have been run. viaeo MeRDry tests.· . I These tests assure~ that the sc;reen area and the data area ·for the A failure here is fatal ancJ will terminate testing . diagnostics are functioning properly. 1. stuck-at test~~~ veriffes that there ar.e no stucK-at-one or stuck-at-zero ireroory locations. 2. Address uniqueness test, verifies that eacn me100ry location is unique atld that no addresses are tied together. . 3. Meroory pattern tests, these tests looK for. ·other types of memory failures such as refreSh ·rails. , · 1 Extensive. These te~>ts are done in,the Boot ROH .. The Boot ROM uses tne video ·. memory as a data s~orage CleVice and .opetation entirely from the CPU board; with no nEroory board plugged 111, is essential for bOoting any device. · Burn-in and 178.rd tel rind problems. This ts. a set of extended meroory tests designed to be run from LisaTest. These tests run 'new and irrproved' pattern tests and are designed to catch very hard to find. memory errors. These tests may run from only minutes, to ·hOurs, or days. The only way for these tests to be accessiable are for the B1Jbt ROM• sown tests to have passed. · . ' .• _ V1de0c1rcu1try tests. This is a basic test of the Video circuit .. Both screen modes are timed to assure that the video is switching properly . 1. VRT /VID/CSVNC test. The hardware provides a two bits in the: status register which allows a program ta iooni tor the video signals :generated by the CPU board. This program tries to determine whether the CPU board video circuitry is working by looking at the VID ano CSVNC releat1onships. · The test checks ti:> see that the:re are transitions an the VRT (Vertical Retrace) bit in .the status register, and makes a rough extimate of the tirre between pulses on this signal . The CSVNC bit is tested for tran$1t1ons and tne VID bit is checked to make sure it is static for a solid black screen. The nufft)er of CSVNC pulses between vertical retraces is che~cKed. The third routit'.le 'first writes an al ternat1ng pattern of ls ano Os to the screen rrerory area, 45 words of then 45 words of 1, etc., until the area is filled. This will create a pattern on the screen of alternate white and blanK lines.…