4-8
Computer Group Literature Center Web Site
Functional Description
4
Note
These 2MB of Flash will follow the EPROMs in memory if S4
segment 2 is set to OFF. The Flash may be read-only or
read/write, depending on the status of Flash write protection (see
below).
Flash write protection is programmable through the VMEchip2 GPIO
register. The address map location of Flash is at $000000 through
$3FFFFF at local reset if switch S4 segment 2 is set to OFF, providing for
the all-Flash mode. In the mixed EPROM/Flash mode, half of the Flash is
accessible at addresses $200000 through $3FFFFF, depending on the state
of the VMEchip2 GPIO2 control bit.
Because the MVME177 uses 1M x 8-bit Flash memory devices and
EPROMs with no download ROM, the software programs the VMEchip2
ROM0 and REV EROM bits properly so that the Flash/EPROM appears at
address $0 after powerup. The hardware is implemented so that the
EPROM/Flash appears at address $00000000 following a local bus reset.
The MVME177 implements Flash write protection by setting or clearing a
control bit (GPIO1) in the VMEchip2 GPIO register, to enable writes by
the software after the download/programming process is complete.
Battery-Backed-Up RAM and Clock
An M48T58 RAM and clock chip is used on the MVME177P. This chip
provides a time-of-day clock, oscillator, crystal, power fail detection,
memory write protection, 8KB of RAM, and a battery in one 28-pin
Table 4-2. EPROM/Flash Control and Configuration
Switch S4
Segment 2
VMEchip2 bit
GPIO2
Memory Configuration
ON
Low
2MB EPROM (lower) and 2MB Flash (upper).
First 2MB Flash accessible (Note).
ON
High
2MB EPROM (lower) and 2MB Flash (upper).
Second 2MB Flash accessible (Note).
OFF
N/A
All 4MB Flash.
Summary of Contents for MVME177P
Page 1: ...MVME177P Single Board Computer Installation and Use V177PA IH1 Edition of October 2000 ...
Page 10: ...x ...
Page 12: ...xii ...
Page 14: ...xiv ...
Page 34: ...1 16 Computer Group Literature Center Web Site Hardware Preparation and Installation 1 ...
Page 48: ...2 14 Computer Group Literature Center Web Site Startup and Operation 2 ...
Page 92: ...C 2 Computer Group Literature Center Web Site Network Controller Data C ...
Page 98: ...D 6 Computer Group Literature Center Web Site Disk Tape Controller Data D ...
Page 108: ...Index IN 6 Computer Group Literature Center Web Site I N D E X ...