DS89C420 Dallas Semiconducotr, DS89C420 Datasheet - Page 34

• Manufacturer Part Number: DS89C420
• Description: Ultra-High-Speed Microcontroller
• Manufacturer: Dallas Semiconducotr

Table 12. Interrupt Summary
*Cleared automatically by hardware when the service routine is vectored to.
**If the interrupt is edge triggered, cleared automatically by hardware when the service routine is vectored to. If the interrupt is level triggered,
The processor indicates that an interrupt condition occurred by setting the respective flag bit. This bit is
set regardless of whether the interrupt is enabled or disabled. Unless marked in Table 12, all of these flags
must be cleared by software.
Timer/Counters
Three 16-bit timers are incorporated in the DS89C420. All three timers can be used as either counters of
external events, where 1-to-0 transitions on a port pin are monitored and counted, or timers that count
oscillator cycles. Table 13 summarizes the timer functions.
Timers 0 and 1 both have three modes of operations. They can each be used as a 13-bit timer/counter, a
16-bit timer/counter, or an 8-bit timer/counter with auto-reload. Timer 0 has a fourth operating mode as
two 8-bit timer/counters without auto-reload. Each timer can also be used as a counter of external pulses
Power-Fail
External Interrupt 0
Timer 0 Overflow
External Interrupt 1
Timer 1 Overflow
Serial Port 0
Timer 2 Overflow
Serial Port 1
External Interrupt 2
External Interrupt 3
External Interrupt 4
External Interrupt 5
Watchdog
INTERRUPT
the flag follows the state of the pin.
VECTOR
0Bh
1Bh
2Bh
3Bh
4Bh
5Bh
33h
03h
13h
23h
43h
53h
63h
NATURAL
ORDER
(Highest)
(Lowest)
10
11
12
0
1
2
3
4
5
6
7
8
9
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PFI (WDCON.4)
IE0 (TCON.1)**
TF0 (TCON.5)*
IE1 (TCON.3)**
TF1 (TCON.7)*
RI_0 (SCON0.0)
TI_0 (SCON0.1)
TF2 (T2CON.7)
EXF2 (T2CON.6)
RI_1 (SCON1.0)
TI_1 (SCON1.1)
IE2 (EXIF.4)
IE3 (EXIF.5)
IE4 (EXIF.6)
IE5 (EXIF.7)
WDIF (WDCON.3) EWDI (EIE.4)
FLAG
EPFI(WDCON.5) N/A
EX0 (IE.0)
ET0 (IE.1)
EX1 (IE.2)
ET1 (IE.3)
ES0 (IE.4)
ET2 (IE.5)
ES1 (IE.6)
EX2 (EIE.0)
EX3 (EIE.1)
EX4 (EIE.2)
EX5 (EIE.3)
ENABLE
LPX0 (IP0.0)
MPX0 (IP1.0)
LPT0 (IP0.1)
MPT0 (IP1.1)
LPX1 (IP0.2)
MPX1 (IP1.2)
LPT1 (IP0.3)
MPT1 (IP1.3)
LPS0 (IP0.4)
MPS0 (IP1.4)
LPT2 (IP0.5)
MPT2 (IP1.5)
LPS1 (IP0.6)
MPS1 (IP1.6)
LPX2 (EIP0.0)
MPX2 (EIP1.0)
LPX3 (EIP0.1)
MPX3 (EIP1.1)
LPX4 (EIP0.2)
MPX4 (EIP1.2)
LPX5 (EIP0.3)
MPX5 (EIP1.3)
LPWDI (EIP0.4)
MPWDI (EIP1.4)
PRIORITY
CONTROL