_ DEC-O-LOG for DW750

_ DOL, DW750-R0001, DW750 APR 84

PROBLEM: On a DATI with offset  and Unibus address 0 and 1 asserted, the 
microsequencer may branch to the DATOB flow. 


CORRECTION: 1. Assert sub 04 UBI UCR AOL for the failing condition with a 
signal from the added ROM.
            2. Change the map latching signal to one from the added ROM.
            3. Update documentation to incorporate Part Revision. 

IN-PLANT EFFECTIVITY: April 6, 1983 

FIELD EFFECTIVITY: This FCO was CANCELLED as of Mar 84. 

QUICK CHECK: E50 is 23-991A9-00. 
                                    

_ DOL, DW750-R0002, DW750 JUL 84

PROBLEM: 1. The DW750 does not efficiently arbitrate for the CMI during 
the UNIBUS interrupts, causing the UDA50 "Interrupt Timeouts" on the 
systems with high CMI activity (CI/DR) which results in a 5-240 second 
VMS "hangs". 2. Concurrent DW750 MAP RAM access by the CPU, and the 
UNIBUS NPR can cause micro-sequencer "first fork" branching errors and 
the glitching of the UNIBUS SSYN, resulting in corrupted NPR's: wrong 
byte offset, CMI "write" for the UNIBUS "DATI (read)", or corrupted 
data strobed into the UNIBUS device on the DATI. 

CORRECTION: 1. ECO L0010-TW004: Alter micro-sequencer flows to the 
DDP.DATO.20 (Direct Data Path DATO) by changing the UCR NXT <3:0> ROM 
at E28, a pluggable ROM. 

IN-PLANT EFFECTIVITY: MAY 84 

FIELD EFFECTIVITY: Retrofit all DW750's to Unit Revision Level 2. The 
minimum acceptable Revision of the L0010 module in spares stock is 
Etch Revision "C", Part Revision "E1". This FCO incorporates ECO's 
L0010-TW004 and LOO10-TW005. 

QUICK CHECK: Presence of E28 as 23-656A2-00. 

The DEC on-site labor charge will be the time required to install and test
the FCO at the then current hourly rate. 

FCO KIT ORDERING: 

EQ-01280-01: FCO, PARTS 
EQ-01280-02: FCO, PARTS 
FA-04552-01: FCO only