HT49R50 Holtek Semiconductor Inc, HT49R50 Datasheet - Page 14

• Manufacturer Part Number: HT49R50
• Description: 8-Bit Microcontroller
• Manufacturer: Holtek Semiconductor Inc

Once an interrupt subroutine is serviced, other
interrupts are all blocked (by clearing the EMI
bit). This scheme may prevent any further in-
terrupt nesting. Other interrupt requests may
take place during this interval, but only the in-
terrupt request flag will be recorded. If a cer-
tain interrupt requires servicing within the
service routine, the EMI bit and the correspond-
ing bit of the INTC0 or of INTC1 may be set in
order to allow interrupt nesting. Once the stack is
Register
INTC0
INTC1
(0BH)
(1EH)
Bit No.
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
Label
EEI0
EEI1
ETBI
ERTI
ET0I
EIF0
EIF1
ET1I
EMI
TBF
RTF
T0F
T1F
¾
¾
¾
Control the master (global) interrupt
(1=enabled; 0=disabled)
Control the external interrupt 0
(1=enabled; 0=disabled)
Control the external interrupt 1
(1=enabled; 0=disabled)
Control the timer/event counter 0 interrupt
(1=enabled; 0=disabled)
External interrupt 0 request flag
(1=active; 0=inactive)
External interrupt 1 request flag
(1=active; 0=inactive)
Internal timer/event counter 0 request flag
(1=active; 0=inactive)
Unused bit, read as ²0²
Control the timer/event counter 1 interrupt
(1=enabled; 0=disabled)
Control the time base interrupt
(1=enabled; 0:disabled)
Control the real time clock interrupt
(1=enabled; 0:disabled)
Unused bit, read as ²0²
Internal timer/event counter 1 request flag
(1=active; 0=inactive)
Time base request flag
(1=active; 0=inactive)
Real time clock request flag
(1=active; 0=inactive)
Unused bit, read as ²0²
INTC register
14
full, the interrupt request will not be acknowl-
edged, even if the related interrupt is enabled,
until the SP is decremented. If immediate service
is desired, the stack should be prevented from be-
coming full.
All these interrupts can support a wake-up
function. As an interrupt is serviced, a control
transfer occurs by pushing the contents of the
PC onto the stack followed by a branch to a sub-
Function
August 18, 1999
HT49C50