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1.4
Restricted RAM and FLASH areas
The ROM Library functions use certain address areas in RAM and FLASH. To ensure that the
ROM Library functions operate properly, the application may not use these locations for storage, nor alter the
contents of these memory locations
1.4.1
Restricted RAM areas
The RAM area C1
through FF
H
ROM Library functions.
1.4.2
Restricted FLASH areas
The FLASH area 57FA
application. The crystal frequency (divided by two) has to be written to that location during FLASH programming
in the production in order to provide the ROM Library functions with the correct timebase for calibration purposes.
For 315 MHz applications a 19.6875 MHz crystal is used and the crystal frequency divided by two has to be written
to that location.
19,687,500 Hz : 2 = 9,843,750 Hz = 963426
The values in FLASH have to be written in the following way:
•
Flash address 57FA
•
Flash address 57FB
•
Flash address 57FC
For 433.92 MHz applications an 18.0800 MHz crystal is used and the crystal frequency divided by two has to be
written to that location.
18,080,000 Hz : 2 = 9,040,000 Hz = 89F080
The values in FLASH have to be written in the following way:
•
Flash address 57FA
•
Flash address 57FB
•
Flash address 57FC
The FLASH address 57FF
otherwise it might result in an unintentionally locked FLASH User Configuration Sector. Locking this sector is
irreversible and shall only be done by either programming the Lockbyte 3 together with writing and locking the
FLASH Code Sector or by a dedicated ROM Library function FlashSetLock().
Note: If
Erase_UserConfigSector()
be ensured that these restricted Flash locations are restored to the proper values.
1.5
8051 Instruction Set Summary
As the SP37 incorporates an 8051 compatible microcontroller,
ROM Library Function Guide
(upper 63 Bytes) of the 256 Bytes RAM is used and overwritten by the
H
through 57FC
is reserved for storage of the crystal frequency to be used in the
H
H
Hz
H
: 96
H
H
: 34
H
H
: 26
H
H
Hz
H
: 89
H
H
: F0
H
H
: 80
H
H
is reserved for Lockbyte 3. This value must not be changed by the application
H
or
WriteFlashUserConfigSectorLine()
Tire Pressure Monitoring Sensor
are used by the application it has to
Figure 1
shows the SP37 OpCode Map.
18
SP37
Introduction
Revision 1.0, 2011-12-15
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