9 EZ-USB Interrupts
9.1
Introduction
The EZ-USB enhanced 8051 responds to the interrupts shown in Table 9-1. Interrupt
sources that are not present in the standard 8051 are shown as checked in the “New” col-
umn. The three interrupts used by the EZ-USB core are shown in bold type.
Table 9-1. EZ-USB Interrupts
New 8051 Interrupt (IRQ name)
Source
Vector (hex) Natural Priority
IE0
INT0# Pin
03
0B
13
1B
23
2B
33
3B
43
4B
53
5B
63
1
2
TF0
Timer 0 Overflow
INT1# Pin
IE1
3
TF1
Timer 1 Overflow
UART0 Rx & Tx
Timer 2 Overflow
WAKEUP# Pin or USB Core
UART1 Rx & Tx
USB Core
4
RI_0 & TI_0
5
P
P
P
P
P
P
P
P
TF2
6
Resume (PFI)
RI_1 & TI_1
USB (INT2)
0
7
8
2
USB Core
9
I C(INT3)
IE4
IE5
IE6
IN4 Pin
10
11
12
INT5# Pin
INT6 Pin
The Natural Priority column in Table 9-1 shows the 8051 interrupt priorities. As
explained in Appendix C, the 8051 can assign each interrupt to a high or low priority
group. The 8051 resolves priorities within the groups using the natural priorities.
9.2
USB Core Interrupts
The EZ-USB core provides three interrupt request types, which are described in the fol-
lowing sections:
Wakeup - After the EZ-USB chip detects USB suspend and the 8051 has entered
its idle state, the EZ-USB core responds to an external signal on its
WAKEUP# pin or resumption of USB bus activity by re-starting the EZ-
USB oscillator and resuming 8051 operation.
EZ-USB TRM v1.9
Chapter 9. EZ-USB Interrupts
Page 9-1
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