DS89C420-QCL Datasheet, PDF (29/139 Pages) Maxim Integrated Products – Ultra-High-Speed Flash Microcontroller User’s Guide

Ultra-High-Speed Flash
Microcontroller User’s Guide
MPT2
Bit 5
MPS0
Bit 4
MPT1
Bit 3
MPX1
Bit 2
MPT0
Bit 1
MPX0
Bit 0
Most Significant Priority Select Bit for Timer 2 Interrupt. This is the most significant bit of the
bit pair MPT2, LPT2 (IP0.5) that designates priority level for the timer 2 interrupt.
Most Significant Priority Select Bit for Serial Port 0 Interrupt. This is the most significant bit of
the bit pair MPS0, LPS0 (IP0.4) that designates priority level for the serial port 0 interrupt
Most Significant Priority Select Bit for Timer 1 Interrupt. This is the most significant bit of the
bit pair MPT1, LPT1 (IP0.3) that designates priority level for the timer 1 interrupt.
Most Significant Priority Select Bit for External Interrupt 1. This is the most significant bit
of the bit pair MPX1, LPX1 (IP0.2) that designates priority level for external interrupt 1
Most Significant Priority Select Bit for Timer 0 Interrupt. This is the most significant bit of the
bit pair MPT0, LPT0 (IP0.1) that designates priority level for the timer 0 interrupt
Most Significant Priority Select Bit for External Interrupt 0. This is the most significant bit of the
bit pair MPX0, LPX0 (IP0.0) that designates priority level for external interrupt 0.
Interrupt priority level for the above sources is assigned using one bit from register IP1 (B1h) and
one bit from IP0 (B8h). The bit from IP1 serves as the most significant bit and the bit from IP0 serves
as the least significant bit in forming a 2-bit binary number. This number represents the priority level.
Higher priority interrupts, when enabled, take precedence over lower priority sources. The power-
fail warning interrupt source is assigned priority level 4.
Most Significant Priority Select Bit Levels
Interrupt Priority 0 (IP0)
7
6
5
SFR B8h
—
LPS1
LPT2
R-1
RW-0
RW-0
R = Unrestricted read, W = Unrestricted write, -n = Value after reset
4
LPS0
RW-0
3
LPT1
RW-0
2
LPX1
RW-0
1
LPT0
RW-0
0
LPX0
RW-0
IP07.0
Bit 7
LPS1
Bit 6
LPT2
Bit 5
LPS0
Bit 4
LPT1
Bit 3
LPX1
Bit 2
LPT0
Bit 1
LPX0
Bit 0
MP (IP1.X)
0
0
1
1
LP (IP0.X)
0
1
0
1
PRIORITY LEVEL
0 (natural priority)
1
2
3 (high priority)
Reserved. Read data is 1.
Least Significant Priority Select Bit for Serial Port 1 Interrupt. LPS1 is the least significant bit
of the bit pair MPS1 (IP1.6), LPS1 that designates priority level for the serial port 1 interrupt.
Least Significant Priority Select Bit for Timer 2 Interrupt. LPT2 is the least significant bit of the
bit pair MPT2 (IP1.5), LPT2 that designates priority level for the Timer 2 interrupt.
Least Significant Priority Select Bit for Serial Port 0 Interrupt. MPS0 is the least significant bit
of the bit pair MPS0 (IP1.4), LPS0 that designates priority level for the serial port 0 interrupt.
Least Significant Priority Select Bit for Timer 1 Interrupt. MPT1 is the least significant bit of the
bit pair MPT1 (IP1.3), LPT1 that designates priority level for the Timer 1 interrupt.
Least Significant Priority Select Bit for External Interrupt 1. MPX1 is the least significant bit of
the bit pair MPX1 (IP1.2), LPX1 that designates priority level for external interrupt 1.
Least Significant Priority Select Bit for Timer 0 Interrupt. MPT0 is the least significant bit of the
bit pair MPT0 (IP1.1), LPT0 that designates priority level for the Timer 0 interrupt.
Least Significant Priority Select Bit for External Interrupt 0. MPX0 is the least significant bit of
the bit pair MPX0 (IP1.0), LPX0 that designates priority level for external interrupt 0.
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