C8051F581-IMR Silicon Labs, C8051F581-IMR Datasheet - Page 110

• Manufacturer Part Number: C8051F581-IMR
• Description: 8-bit Microcontrollers - MCU 50MIPS 128kB 8kB SPI
• Manufacturer: Silicon Labs

Specifications of C8051F581-IMR

• Rohs: yes
• Core: 8051
• Processor Series: C8051
• Data Bus Width: 8 bit

C8051F58x/F59x
On exit from the PCA interrupt service routine, the CIP-51 will return to the CAN0 ISR. On execution of the
RETI instruction, SFR Page 0x00 used to access the PCA registers will be automatically popped off of the
SFR Page Stack, and the contents of the SFRNEXT register will be moved to the SFRPAGE register. Soft-
ware in the CAN0 ISR can continue to access SFRs as it did prior to the PCA interrupt. Likewise, the con-
tents of SFRLAST are moved to the SFRNEXT register. Recall this was the SFR Page value 0x00 being
used to access SPI0DAT before the CAN0 interrupt occurred. See Figure 13.5.
110
Figure 13.4. SFR Page Stack Upon PCA Interrupt Occurring During a CAN0 ISR
SFRPAGE
SFRNEXT
SFRNEXT
pushed to
SFRLAST
pushed to
(SPI0DAT)
SFRPAGE on PCA
pushed on stack in
(CAN0)
SFR Page 0x0
Automatically
(PCA)
0xC
0x0
0x0
interrupt
Rev. 1.2
SFRPAGE
SFRNEXT
SFRLAST