Other Software Considerations; Mram; Real Time Clock; Quad Uart - SMART Embedded Computing MVME2500 Installation & Use Manual

7.6

Other Software Considerations

This section provides programming information in relation to various board components.
7.6.1

MRAM

The MVME2500 provides 512K bytes of fast, non-volatile storage in the form of
Magnetoresistive Random Access Memory (MRAM). The MRAM is directly accessible by
software using processor load and store instructions similar to the DRAM. The difference
is that the MRAM retains its contents even if the board is power cycled. The MRAM is
accessed through the LBC.
7.6.2

Real Time Clock

The MVME2500 provides a battery back-up DS1375 Real Time Clock (RTC) chip. The RTC
chip provides time keeping and alarm interrupts. It is an I
2
the I C bus address at 0x68.
If the RTC is stopped or started by default, the following commands are necessary to start
RTC in u-boot.
date - get/set/reset date & time
Usage: date [MMDDhhmm[[CC]YY][.ss]]
date reset
- without arguments: print date & time
- with numeric argument: set the system date & time
- with 'reset' argument: reset the RTC
7.6.3

Quad UART

The MVME2500 console RS-232 port is driven by the UART built into the P20x0 QorIQ
chip. Additionally, the MVME2500 has a Quad UART chip which provides four 16550
compatible UART. 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. The four UART physically connect to RS-232 DB9 serial ports through the
RTM.
MVME2500 Installation and Use (6806800L01S)
Programming Model
2
C device and is accessed through
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