89C5121-SK1 Atmel, 89C5121-SK1 Datasheet - Page 47

• Manufacturer Part Number: 89C5121-SK1
• Description: KIT SMART CARD FOR AT89C5121
• Manufacturer: Atmel
• Type: Smart Cardr

Specifications of 89C5121-SK1

• Contents: Board
• For Use With/related Products: AT89C5121
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: T89C5121-SK1; T89C5121-SK1

Interrupt System
Figure 23. Interrupt Control System
4164G–SCR–07/06
INT1/OE
CPRES
SCI
TF1
RI
TI
INT0
TF0
Rxd
1
0
0
1
OELEV
CPLEV
RXEN
OEEN
PRESEN
The T8xC5121 has a total of 6 interrupt vectors: four external interrupts (INT0, INT1/OE,
CPRES, RxD), two Timer 0 interrupts (Timer 0s 0 and 1), serial port interrupt and Smart
Card Interface interrupt. These interrupts are shown in Figure 23.
Each of the interrupt sources can be individually enabled or disabled by setting or clear-
ing a bit in the Interrupt Enable register (see Figure 32). This register also contains a
global disable bit, which must be cleared to disable all interrupts at once.
Each interrupt source can also be individually programmed to one of four priority levels
by setting or clearing a bit in the Interrupt Priority register (see Figure 36) and in the
Interrupt Priority High register (see Figure 38). Table 30 shows the bit values and priority
levels associated with each combination.
Table 30. Priority Level Bit Values
IT1
PRESIT
0
1
IPH.x
TCON Reg.
TCON reg.
0
0
1
1
RXIT
IE1
0
1
The selection bits
IT0
except IT1 (TCON)
are in ISEL Reg.
IE0
IP.x
Individual
Enable
0
1
0
1
ET0
EX0
EX1
ET1
ESCI
ES
Global
Enable
IPH0, IPL0
IPH1, IPL1
3
0
0
3
0
3
0
3
0
3
0
3
Interrupt Level Priority
Low Priority
Interrupt
3 (Highest)
High Priority
Interrupt
0 (Lowest)
1
2
A/T8xC5121
Sequence
Interrupt
Polling
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