AN1365 Datasheet, PDF (8/13 Pages) STMicroelectronics – GUIDELINES FOR MIGRATING ST72C254 APPLICATIONS TO ST72F264

GUIDELINES FOR MIGRATING ST72C254 APPLICATIONS TO ST72F264
4.2 REGISTER MODIFICATIONS
4.2.1 CRSR Register
The CRSR (Clock, Reset and Supply Register) register has been replaced by the SICSR
(System Integrity Control/Status Register) register (see Figure 5.). This SICSR register con-
tains the bits related to the AVD feature.
Figure 5. CRSR Register Changes
CRSR (0025h)
Clock Reset and Supply Register
7
0
0
0
0
LVD
RF
0
CS- CSS WDG
SIE D RF
SICSR (0025h)
System Integrity Control/Status Register
7
0
0
AVDI AVD LVD
E F RF
0
0
0
WDG
RF
4.2.2 SPI/SS pin
The SPI SS pin alternate function is controlled from the MISCR2 like previously, but these
control bits have also been duplicated into the SPICSR register in three unused locations.
Figure 6. SS pin control
7
0
0
0
0
0 MOD SOD SSM SSI
MISCR2 (0040h)
7
0
SPIF
WCO
L
OR
MOD
F
0
SOD SSM SSI
SPICSR (0023h)
SPI Control/Status Register
Both registers can be used to control the SS pin.
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