Other Software Considerations; Mram; Real Time Clock; Quad Uart - SMART Embedded Computing MVME4100 Programmer's Reference Manual

4.12

Other Software Considerations

This section provides information on various board components.
4.12.1

MRAM

The MVME4100 provides 512 K bytes of fast non-volatile storage in the form of MRAM
(Magnetoresistive Random Access Memory). The MRAM is directly accessible by software
in the same manner as the DRAM (that means using processor load and store instructions).
The only difference is that the MRAM retains its contents even if the board is power cycled.
The MRAM is accessed through the LBC.
The MRAM may be write protected by hardware switches and/or hardware registers. To
write the MRAM successfully, software must first ensure that the MRAM's write protection
mechanisms have been modified to allow write access to the MRAM.
4.12.2

Real Time Clock

The MVME4100 provides a battery backed up DS1375 RTC (Real TIme Clock) chip. The
RTC chip provides time keeping and alarm interrupts. The RTC chip is an I
is accessed via the I
4.12.3

Quad UART

The MVME4100 console RS-232 port is driven by the UART built into the MPC8548E chip.
In addition, the MVME4100 includes a Quad UART chip which provides the user with four
additional 16550 compatible UARTs. These additional UARTs are internally accessed
through the LBC bus. The Quad UART chip clock input (which is internally divided to
generate the baud rate) is 1.8432Mhz. These four UARTS physically connect to RS-232
DB9 serial ports via the RTM. For programming details refer to the vendor's data sheet
referenced in Appendix B.
MVME4100 Single Board Computer Programmer's Reference (6806800H19D)
2
C bus at address 0xD0.
Programming Details
2
C device and
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