HT56R23 datasheet(86/127 Pages) HOLTEK

86 / 127 page

HT56R22/HT56R23/HT56R24/HT56R25/HT56R26

Rev. 1.30

December 26, 2014

If an interrupt requires immediate servicing while the

program is already in another interrupt service routine,

the EMI bit should be set after entering the routine, to al-

low interrupt nesting. If the stack is full, the interrupt re-

quest will not be acknowledged, even if the related

interrupt is enabled, until the Stack Pointer is decre-

mented. If immediate service is desired, the stack must

be prevented from becoming full. In case of simulta-

neous requests, the accompanying diagram shows the

priority that is applied. All of the interrupt request flags

when set will wake-up the device if it is in SLEEP or

IDLE Mode, however to prevent a wake-up from occur-

ring the corresponding flag should be set before the de-

vice is in SLEEP or IDLE Mode.

External Interrupt

For an external interrupt to occur, the global interrupt en-

able bit, EMI, and external interrupt enable bits, INT0E

and INT1E, must first be set. Additionally the correct in-

terrupt edge type must be selected using the INTEDGE

choose the trigger edge type. An actual external inter-

rupt will take place when the external interrupt request

flag, INT0F or INT1F, is set, a situation that will occur

when a transition, whose type is chosen by the edge se-

lect bit, appears on the INT0 or INT1 pin. The external

interrupt pins are pin-shared with the I/O pins PA4 and

PA6 and can only be configured as external interrupt

pins if their corresponding external interrupt enable bit in

the INTC0 register has been set. The pin must also be

setup as an input by setting the corresponding PAC.4

and PAC.6 bits in the port control register. When the in-

terrupt is enabled, the stack is not full and the correct

transition type appears on the external interrupt pin, a

subroutine call to the external interrupt vector at location

04H or 08H, will take place. When the interrupt is ser-

viced, the external interrupt request flags, INT0F or

INT1F, will be automatically reset and the EMI bit will be

automatically cleared to disable other interrupts. Note

that any pull-high resistor selections on this pin will re-

main valid even if the pin is used as an external interrupt

input.

The INTEDGE register is used to select the type of active

edge that will trigger the external interrupt. A choice of ei-

ther rising and falling edge types can be chosen along

with an option to allow both edge types to trigger an ex-

ternal interrupt. Note that the INTEDGE register can also

be used to disable the external interrupt function.

· INTEDGE Register - All Devices

Bit

76543210

Name

¾¾¾¾

INT1S1

INT1S0

INT0S1

INT0S0

R/W

¾¾¾¾

R/W

POR

¾¾¾¾

0000

Bit 7~4

unimplemented, read as

²0²

Bit 3~2

INT1S1, INT1S0: interrupt edge control for INT1 pin

00: disable

01: rising edge

10: falling edge

11: rising and falling edges

Bit 1~0

INT0S1, INT0S0: interrupt edge control for INT0 pin

00: disable

01: rising edge

10: falling edge

11: rising and falling edges

HT56R23 Datasheet(PDF) 86 Page - Holtek Semiconductor Inc

HT56R23 Datasheet(HTML) 86 Page - Holtek Semiconductor Inc

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL