ST92185B STMicroelectronics, ST92185B Datasheet - Page 55

• Manufacturer Part Number: ST92185B
• Description: 16k/24k/32k Rom Hcmos Mcu With On-screen-display
• Manufacturer: STMicroelectronics

INTERRUPT REGISTERS (Cont’d)
EXTERNAL INTERRUPT VECTOR REGISTER
(EIVR)
R246 - Read/Write
Register Page: 0
Reset value: xxxx 0110b (x6h)
Bit 7:4 = V[7:4]: Most significant nibble of External
Interrupt Vector .
These bits are not initialized by reset. For a repre-
sentation of how the full vector is generated from
V[7:4] and the selected external interrupt channel,
refer to
Bit 3 = TLTEV: Top Level Trigger Event bit.
This bit is set and cleared by software.
0: Select falling edge as NMI trigger event
1: Select rising edge as NMI trigger event
Bit 2 = TLIS: Top Level Input Selection .
This bit is set and cleared by software.
0: Watchdog End of Count is TL interrupt source
1: NMI is TL interrupt source
Bit 1 = IA0S: Interrupt Channel A0 Selection.
This bit is set and cleared by software.
0: Watchdog End of Count is INTA0 source
1: External Interrupt pin is INTA0 source
Bit 0 = EWEN: External Wait Enable.
This bit is set and cleared by software.
V7
7
V6
Figure
V5
27.
V4
TLTEV TLIS IAOS EWEN
0
0: WAITN pin disabled
1: WAITN pin enabled (to stretch the external
Note: For more details on Wait mode refer to the
section describing the WAITN pin in the External
Memory Chapter.
NESTED INTERRUPT CONTROL (NICR)
R247 - Read/Write
Register Page: 0
Reset value: 0000 0000 (00h)
Bit 7 = TLNM: Top Level Not Maskable .
This bit is set by software and cleared only by a
hardware reset.
0: Top Level Interrupt Maskable. A top level re-
1: Top Level Interrupt Not Maskable. A top level
Bit 6:0 = HL[6:0]: Hold Level x
These bits are set by hardware when, in Nested
Mode, an interrupt service routine at level x is in-
terrupted from a request with higher priority (other
than the Top Level interrupt request). They are
cleared by hardware at the iret execution when
the routine at level x is recovered.
TLNM HL6
memory access cycle).
quest is generated if the IEN, TLI and TLIP bits
=1
request is generated if the TLIP bit =1
7
HL5
ST92185B - INTERRUPTS
HL4
HL3
HL2
HL1
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HL0
0