CY8C34_11 CYPRESS [Cypress Semiconductor], CY8C34_11 Datasheet - Page 18

• Manufacturer Part Number: CY8C34_11
• Manufacturer: CYPRESS [Cypress Semiconductor]

Document Number: 001-53304 Rev. *K
When an interrupt is pending, the current instruction is completed and the program
counter is pushed onto the stack. Code execution then jumps to the program address
provided by the vector. After the ISR is completed, a RETI instruction is executed
and returns execution to the instruction following the previously interrupted
instruction. To do this the RETI instruction pops the program counter from the stack.
If the same priority level is assigned to two or more interrupts, the interrupt with the
lower vector number is executed first. Each interrupt vector may choose from three
Notes
1: Interrupt triggered asynchronous to the clock
2: The PEND bit is set on next active clock edge to indicate the interrupt arrival
3: POST bit is set following the PEND bit
4: Interrupt request and the interrupt number sent to CPU core after evaluation priority (Takes 3 clocks)
5: ISR address is posted to CPU core for branching
6: CPU acknowledges the interrupt request
Multiple I/O interrupt vectors
Software can send interrupts
Software can clear pending interrupts
ACTIVE_INT_NUM
INT_VECT_ADDR
INT_INPUT
PEND
POST
(#10)
IRA
CLK
IRQ
IRC
1
Interrupt generation and posting to CPU
Arrival of new Interrupt
2
Pend bit is set on next system clock active edge
NA
NA
3
Interrupt is posted to ascertain the priority
4
Interrupt request sent to core for processing
5
CPU Response
address is posted to core
The active interrupt ISR
Figure 4-2. Interrupt Processing Timing Diagram
0x0010
6
Int. State
number is posted to core
Clear
The active interrupt
7
IRQ cleared after receiving IRA
8
Completing current instruction and branching to vector address
interrupt sources: Fixed Function, DMA, and UDB. The fixed function interrupts are
direct connections to the most common interrupt sources and provide the lowest
resource cost connection. The DMA interrupt sources provide direct connections to
the two DMA interrupt sources provided per DMA channel. The third interrupt source
for vectors is from the UDB digital routing array. This allows any digital signal
available to the UDB array to be used as an interrupt source. Fixed function interrupts
and all interrupt sources may be routed to any interrupt vector using the UDB
interrupt source connections.
Figure 4-2
Figure 4-3
9
POST and PEND bits cleared after IRQ is sleared
on page 18 represents typical flow of events when an interrupt triggered.
on page 19 shows the interrupt structure and priority polling.
NA
10
PSoC
Complete ISR and return
®
S
S
S
S
S
S
S
S
S
S
S
3: CY8C34 Family
11
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Data Sheet
Page 18 of 126
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