AN2135SC Cypress Semiconductor Corp, AN2135SC Datasheet - Page 330

• Manufacturer Part Number: AN2135SC
• Description: IC MCU 8051 8K RAM 24MHZ 44QFP
• Manufacturer: Cypress Semiconductor Corp
• Series: EZ-USB®r

Specifications of AN2135SC

• Applications: USB Microcontroller
• Core Processor: 8051
• Program Memory Type: ROMless
• Controller Series: AN213x
• Ram Size: 8K x 8
• Interface: I²C, USB
• Number Of I /o: 8
• Voltage - Supply: 3 V ~ 3.6 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 44-QFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: 428-1308

Table C-19. provides a summary of interrupt sources, flags, enables, and priorities.
C.4.2 Interrupt Priorities
There are two stages of interrupt priority assignment, interrupt level and natural priority. The
interrupt level (highest, high, or low) takes precedence over natural priority. The USB wakeup
interrupt, if enabled, always has highest priority and is the only interrupt that can have highest
priority. All other interrupts can be assigned either high or low priority.
In addition to an assigned priority level (high or low), each interrupt also has a natural priority,
as listed in Table C-18.. Simultaneous interrupts with the same priority level (for example,
both high) are resolved according to their natural priority. For example, if INT0 and INT2 are
both programmed as high priority, INT0 takes precedence due to its higher natural priority.
Once an interrupt is being serviced, only an interrupt of higher priority level can interrupt the
service routine of the interrupt currently being serviced.
C - 34
RESUME
INT0
TF0
INT1
TF1
TI_0 or RI_0
TF2 or EXF2
TI_1 or RI_1
INT2
INT3
INT4
INT5
INT6
Interrupt
Table C-18. Interrupt Natural Vectors and Priorities
Appendix C: 8051 Hardware Description
USB Wakeup (resume) interrupt
External interrupt 0
Timer 0 interrupt
External interrupt 1
Timer 1 interrupt
Serial port 0 interrupt
Timer 2 interrupt
Serial port 1 interrupt
USB interrupt
I
External interrupt 4
External interrupt 5
External interrupt 6
2
C interrupt
Description
Priority
Natural
12
11
0
1
2
3
4
5
6
7
8
9
4
Interrupt
Vector
0Bh
1Bh
2Bh
3Bh
4Bh
5Bh
63H
33h
03h
13h
23h
43h
53h
EZ-USB TRM v1.9