Themis USPIIi-1v, Hardware Manual

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USPIIi-1v Hardware Manual
4-4
Themis Computer
The 8 MB User Flash is made of two 4Mx8 bit Sharp LH28F320. User Flash contains the OpenBoot PROM
(OBP) specially configured for the Sun mode.
Either the System Flash or the User Flash may be used for board boot-up, selectable by jumper setting. Make
sure that your selection and the code in PROM it corresponds to, match your effective keyboard/mouse
configuration. For more information on selecting between User Flash and System Flash, refer to Section 6.1.2,
"Boot Address Decoder," on page 6-1.
4.1.12 TOD and NVRAM
The Non-Volatile Memory RAM and a Time of Day (TOD) clock are both contained in the timekeeper chip
(SGS-Thomson, M48T59Y-70MH1). The NVRAM has its own lithium battery to operate the clock and
maintain the contents of the NVRAM during power-off situations. The battery device is an SGS Thomson
Microelectronics BT1402. This single lithium battery provides backup for approximately 10 years and the
real-time clock circuitry provides accuracy of +/- one (1) second per day.
NVRAM and TOD are programmed using the FORTH toolkit in Open Boot Program (OBP).
4.2 Memory Subsystem
The USPII i -1v supports up to two coplanar memory modules of either 64 MB, 128 MB, 256 MB or 512 MB
each. The modules may be combined to provide 64 MB, 128 MB, 256 MB, 512 MB or 1024 MB in a single
slot configuration.
The memory design includes Error Correction Code (ECC). A single bit error in a 64 bit word is corrected
without loss of a cycle. CAS before RAS refresh is used and CAS, RAS, and WE are buffered on the memory
module.
Table 4-1. Flash EPROM Jumpers
Jumper Setting Description
JP1401 on position 1-2 (Default) System Flash Write Protected
JP1401 on position 2-3 System Flash Write Enabled
JP3302 on position 1-2 or Un-installed (Default) User Flash Write Protected
JP3302 on position 2-3 User Flash Write Enabled
JP3304 on position 2-3 or Un-installed
a
a. The default position of this jumper depends on the board configuration (PS/2 mode or Sun mode)
Boot from System Flash
JP3304 on position 1-2 Boot from User Flash
JP3303 on position 2-3 or Un-installed Boot from System or User Flash, depending on
JP3304
JP3303 on position 1-2 Boot from external ROMBO connector