20-101-1247 Rabbit Semiconductor, 20-101-1247 Datasheet - Page 56

• Manufacturer Part Number: 20-101-1247
• Description: CORE MODULE RCM5450W
• Manufacturer: Rabbit Semiconductor

Specifications of 20-101-1247

• Module/board Type: MPU Core Module
• Wireless Frequency: 73.73 MHz
• For Use With/related Products: RCM5450W
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 316-1149

The
tents of the user block that you are using in your application (the calibration constants in
the reserved area and the ID block are protected).
5.2.4 SRAM Use
The RCM5400W module has a battery-backed data SRAM and a program-execution
SRAM. Dynamic C provides the
placed into the battery-backed SRAM. The compiler generates code that maintains two
copies of each protected variable in the battery-backed SRAM. The compiler also generates
a flag to indicate which copy of the protected variable is valid at the current time. This flag
is also stored in the battery-backed SRAM. When a protected variable is updated, the
“inactive” copy is modified, and is made “active” only when the update is 100% complete.
This assures the integrity of the data in case a reset or a power failure occurs during the
update process. At power-on the application program uses the active copy of the variable
pointed to by its associated flag.
The sample code below shows how a protected variable is defined and how its value can
be restored.
The
battery-backed SRAM without affecting the performance of the application program. Data
integrity is not assured when a reset or power failure occurs during the update process.
Additional information on
User’s Manual.
5.2.4.1 SRAM Chip Select Considerations
The basic SRAM memory on Rabbit-based boards is always connected to /CS1, /OE1, and
/WE1. Both the data SRAM and the program execution fast SRAM on the RCM5400W
share /OE1.
The BIOS-defined macro,
high). The macro may be redefined in the BIOS to 1, which will set a bit in the MMIDR
register that forces /CS1 to stay enabled (low). This capability is normally used to speed up
access time for battery-backed SRAM as long as no other memory chips are connected to
/OE1 and /WE1. Therefore, the
of 0 to avoid conflicts between the data SRAM and the program execution fast SRAM.
5.2.5 Wi-Fi Drivers
Complete information on the Wi-Fi libraries and function calls is provided in Chapter 6.
Additional information on TCP/IP is provided in the Dynamic C TCP/IP User’s Manual.
50
USERBLOCK_CLEAR.C
bbram
main() {
protected int state1, state2, state3;
...
_sysIsSoftReset();
keyword may also be used instead if there is a need to store a variable in
bbram
CS1_ALWAYS_ON
sample program shows you how to clear and write the con-
CS1_ALWAYS_ON
protected
and
// restore any protected variables
protected
, is set to 0 by default to disable /CS1 (set it
keyword to identify variables that are to be
macro must remain at its default setting
variables is available in the Dynamic C
RabbitCore RCM5400W