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INSTRUCTION SET
S3C80M4/F80M4
6-40
EI
—
Enable Interrupts
EI
Operation:
SYM
(0)
←
1
An EI instruction sets bit zero of the system mode register, SYM.0 to "1". This allows interrupts to
be serviced as they occur (assuming they have highest priority). If an interrupt's pending bit was
set while interrupt processing was disabled (by executing a DI instruction), it will be serviced
when you execute the EI instruction.
Flags:
No flags are affected.
Format:
Bytes Cycles Opcode
(Hex)
opc
1 4 9F
Example:
Given: SYM = 00H:
EI
If the SYM register contains the value 00H, that is, if interrupts are currently disabled, the
statement "EI" sets the SYM register to 01H, enabling all interrupts. (SYM.0 is the enable bit for
global interrupt processing.)
Summary of Contents for S3C80M4/F80M4
Page 1: ...S3C80M4 F80M4 8 BIT CMOS MICROCONTROLLERS USER S MANUAL Revision 1 ...
Page 44: ...ADDRESS SPACES S3C80M4 F80M4 2 20 NOTES ...
Page 84: ...CONTROL REGISTERS S3C80M4 F80M4 4 26 NOTES ...
Page 102: ...INTERRUPT STRUCTURE S3C80M4 F80M4 5 18 NOTES ...
Page 190: ...INSTRUCTION SET S3C80M4 F80M4 6 88 NOTES ...
Page 202: ...RESET and POWER DOWN S3C80M4 F80M4 8 6 NOTES ...
Page 216: ...8 BIT TIMER 0 S3C80M4 F80M4 11 4 NOTES ...
Page 220: ...8 BIT PULSE WIDTH MODULATION S3C80M4 F80M4 12 4 NOTES ...
Page 230: ...ELECTRICAL DATA S3C80M4 F80M4 13 10 NOTES ...