cop8acc7 National Semiconductor Corporation, cop8acc7 Datasheet - Page 21

• Manufacturer Part Number: cop8acc7
• Description: 8-bit Cmos Otp Microcontroller With 16k Memory And High Resolution A/d
• Manufacturer: National Semiconductor Corporation

Analog Function Block
Reset
The state of the Analog Block immediately after RESET is as
follows:
1. The CMPSL Register is set to all zeros
2. The Comparator is disabled
3. The Constant Current Source is disabled
4. CMPNEG is turned off
5. The Port I inputs are electrically isolated from the com-
6. The Capture Timer input is connected to GND
7. CMPISEL0–CMPISEL2 are set to zero
8. All Port I inputs are selected to the default digital input
The comparator outputs have the same specification as
Ports L and G except that the rise and fall times are sym-
metrical.
parator
mode
CMPISEL2
0
0
0
0
1
1
1
1
Control Bit
CMPISEL1
0
0
1
1
0
0
1
1
(Continued)
TABLE 4. Comparator Input Selection
CMPISEL0
0
1
0
1
0
1
0
1
21
Interrupts
INTRODUCTION
Each device supports eight vectored interrupts. Interrupt
sources include Timer 0, Timer 1, Timer 2, Timer 3, Port L
Wakeup, Software Trap, MICROWIRE/PLUS, and External
Input.
All interrupts force a branch to location 00FF Hex in program
memory. The VIS instruction may be used to vector to the
appropriate service routine from location 00FF Hex.
The Software trap has the highest priority while the default
VIS has the lowest priority.
Each of the 8 maskable inputs has a fixed arbitration ranking
and vector.
Figure 14 shows the Interrupt Block Diagram.
Input
Neg.
I1
I1
I1
I1
I1
I1
I1
I1
Input Source
Comparator
I2 CH2
I2 CH2
I3 CH3
I0 CH1
I4 CH4
I5 CH5
I6 CH6
V
Input
Pos.
Ref.
CC
/2
Comparator
Output
I3
I7
I7
I7
I7
I7
I7
I7
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