C8051F50x-F51x
SFR Page 0x0
Automatically
popped off of the
stack on return from
interrupt
0xC
SFRPAGE
SFRNEXT
SFRLAST
(CAN0)
0x0
SFRNEXT
popped to
SFRPAGE
(SPI0DAT)
SFRLAST
popped to
SFRNEXT
Figure 13.5. SFR Page Stack Upon Return From PCA Interrupt
On the execution of the RETI instruction in the CAN0 ISR, the value in SFRPAGE register is overwritten
with the contents of SFRNEXT. The CIP-51 may now access the SPI0DAT register as it did prior to the
interrupts occurring. See Figure 13.6.
Rev. 1.1
105