19 Mar
2014
19 Mar
'14
4:32 a.m.
Am 05.03.2014 15:28, schrieb Steve Lafferty:
Regarding comments on the design, Design Requirement
#3 precludes SMT
parts, so the FRAM option is out.
Why? SMT saves board space and is not that hard
to solder as some people
think!
Actually, given the factors of its
limited cycles and 10-year retention,
Fujitsu MB85R1001ANC-GE1, 1MBit FRAM:
A pdp8 has at best 1.2us cycle time. Each cycle has to be modeled as two
accesses. Makes an access cycle time of 600ns. Frequency is 1,6666...
MHz. Oops... Only 6000 seconds of operation!
10^10 sounded so much :-(