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CONTROL REGISTERS
S3P80C5/C80C5/C80C8
4-26
SYM
— System Mode Register
DEH
Set 1
Bit Identifier
.7
.6
.5
.4
.3
.2
.1
.0
RESET
RESET
Value
0
–
–
x
x
x
0
0
Read/Write
R/W
–
–
R/W
R/W
R/W
R/W
R/W
Addressing Mode
Register addressing mode only
.7
Tri-State External Interface Control Bit
(1)
0
Normal operation (disable tri-state operation)
1
Set external interface lines to high impedance (enable tri-state operation)
.6–.5
Not used for S3P80C5/C80C5/C80C8.
.4–.2
Fast Interrupt Level Selection Bits
(2)
0
0
0
IRQ0
0
0
1
IRQ1
0
1
0
Not used for
0
1
1
S3P80C5/C80C5/C80C8.
1
0
0
1
0
1
1
1
0
IRQ6
1
1
1
IRQ7
.1
Fast Interrupt Enable Bit
(3)
0
Disable fast interrupt processing
1
Enable fast interrupt processing
.0
Global Interrupt Enable Bit
(4)
0
Disable global interrupt processing
1
Enable global interrupt processing
NOTES
:
1.
Because an external interface is not implemented for the S3P80C5/C80C5/C80C8, SYM.7 must always be "0".
2.
You can select only one interrupt level at a time for fast interrupt processing.
3.
Setting SYM.1 to "1" enables fast interrupt processing for the interrupt level currently selected by SYM.2–SYM.4.
4.
Following a reset, you must enable global interrupt processing by executing an EI instruction (not by writing a "1"
to SYM.0).
Summary of Contents for S3P80C5
Page 2: ...S3P80C5 C80C5 C80C8 8 BIT CMOS MICROCONTROLLERS USER S MANUAL Revision 1 ...
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Page 49: ...ADDRESS SPACES S3P80C5 C80C5 C80C8 2 20 NOTES ...
Page 197: ...INSTRUCTION SET S3P80C5 C80C5 C80C8 6 88 NOTES ...
Page 201: ...CLOCK CIRCUITS S3P80C5 C80C5 C80C8 7 4 NOTES ...
Page 237: ...TIMER 1 S3P80C5 C80C5 C80C8 11 6 NOTES ...
Page 245: ...COUNTER A S3P80C5 C80C5 C80C8 12 8 NOTES ...
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