Does anyone know if the DS1220AD will work as a direct replacement for the DS1220Y NVRAM chip currently installed in the HP-3458A? There is a timing difference between the two devices, as explained in Maxim AN 202. "the "Y" parts had a reset timeout on the order of milliseconds while the "AD" parts have a timeout of 125ms. When replacing the Y part with the AD part, it must be determined that the controlling processor does not become active during a power-up cycle for at least 125ms to ensure that the NV SRAM is available before the processor attempts a memory access." There have been documented cases where the new DS1220AD part will not work in circuits designed with the DS1220Y (now discontinued). I would like to know if anyone has successfully utilized the DS1220AD before proceeding to buy the parts. Similar question for the DS1230Y and DS1230AD. Thanks, Randy Evans

-------- In message <CANwu9JbdybQPrSOrQn6xRM0M5YpaL2t40i33+bZMJcDJjO=fqg@mail.gmail.com> , Randy Evans writes: >Does anyone know if the DS1220AD will work as a direct replacement for >the DS1220Y >NVRAM chip currently installed in the HP-3458A? There is a timing >difference between the two devices, as explained in Maxim AN 202. I don't think that difference will make any difference. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence.

Actually, it could make a difference depending on when the processor tries to access the memory on start up. The Maxim app note mentions that many legacy programs designed for the DS1220Y may not work with the DS122AD, hence the reason for the question. I really would like to hear from someone that has actually successfully replaced the DS1220Y with the DS1220AD, since the DS1220Y is no longer avaialble.. On Fri, Nov 10, 2017 at 5:20 AM, Poul-Henning Kamp <phk@phk.freebsd.dk> wrote: > -------- > In message <CANwu9JbdybQPrSOrQn6xRM0M5YpaL2t40i33+bZMJcDJjO=fqg@mail. > gmail.com> > , Randy Evans writes: > > >Does anyone know if the DS1220AD will work as a direct replacement for > >the DS1220Y > >NVRAM chip currently installed in the HP-3458A? There is a timing > >difference between the two devices, as explained in Maxim AN 202. > > I don't think that difference will make any difference. > > > -- > Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 > phk@FreeBSD.ORG | TCP/IP since RFC 956 > FreeBSD committer | BSD since 4.3-tahoe > Never attribute to malice what can adequately be explained by incompetence. >