HT85F2270 datasheet(114/226 Pages) HOLTEK

114 / 226 page

Rev. 1.00

114 of ��6

�a� 1�� 01�

Standard 8051 8-Bit Flash MCU

HT85F2260/HT85F2270/HT85F2280

A/D Converter Interrupt

The A/D Converter Interrupt is controlled by the termination of an A/D conversion process. An

A/D Converter Interrupt request will take place when the A/D Converter Interrupt request flag,

IADC, is set, which occurs when the A/D conversion process finishes. To allow the program to

branch to its respective interrupt vector address, the global interrupt enable bit, EAL, and A/D

Interrupt enable bit, EADC, must first be set. When the interrupt is enabled, the stack is not full

and the A/D conversion process has ended, a subroutine call to the A/D Converter Interrupt vector,

will take place. When the interrupt is serviced, the A/D Converter Interrupt flag, IADC, will be

automatically cleared. The EAL bit must be cleared by the application program to disable other

interrupts.

Timer/Counter Interrupt

For a Timer Counter interrupt to occur, the global interrupt enable bit, EAL, and the corresponding

timer interrupt enable bit, ETn, must first be set. An actual Timer Counter interrupt will take place

when the Timer Counter request flag, TFn, is set, a situation that will occur when the relevant

Timer Counter overflows. When the interrupt is enabled, the stack is not full and a Timer Counter

n overflow occurs, a subroutine call to the relevant timer interrupt vector, will take place. When the

interrupt is serviced, the timer interrupt request flag, TFn (n=0, 1, 3), will be automatically reset,

while the TF2 bit must be cleared by the application program, and the EAL bit must also be cleared

using the application program to disable other interrupts.

Time Base Interrupts

The function of the Time Base Interrupt is to provide a regular time signal in the form of an

internal interrupt. It is basically a simple timer whose interrupt is generated when it overflows.

When this happen its respective interrupt request flag, TBF will be set. To allow the program to

branch to its respective interrupt vector address, the global interrupt enable bit, EAL and Time

Base enable bit, ETB, must first be set. When the interrupt is enabled, the stack is not full and the

Time Base overflows, a subroutine call to its respective vector locations will take place. When the

interrupt is serviced, the respective interrupt request flag, TBF, will be automatically reset but the

EAL bit must be cleared by the application program to disable other interrupts.

The purpose of the Time Base Interrupt is to provide an interrupt signal at fixed time periods. Their

clock sources originate from the internal clock source fTBC. This fTBC input clock passes through a

divider, the division ratio of which is selected by programming the appropriate bits in the TBCR

the Time Base interrupt period, can originate from the system clock, LIRC or LXT oscillator.

Time Base Interrupt

fTBC

�8~�1�

fSYS/4

TBCK[1:0]

TBS[�:0]

f��K

fSYS/1�8

�

Time Base Clock Source Select

HT85F2270 Datasheet(PDF) 114 Page - Holtek Semiconductor Inc

HT85F2270 Datasheet(HTML) 114 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