HT45R37 datasheet(37/100 Pages) HOLTEK

37 / 100 page

HT45R37

Rev. 1.10

January 29, 2010

Example: using an EOCB polling method to detect the end of conversion

clr

EADI

; disable ADC interrupt

mov

a,00000001B

mov

ACSR,a

; select fSYS/8 as A/D clock and turn on ADONB bit

mov

a,00100000B

; setup ADCR register to configure Port PB0~PB3

; as A/D inputs

mov

ADCR,a

; and select AN0 to be connected to the A/D converter

; As the Port B channel bits have changed the

; following START

; signal (0-1-0) must be issued

; instruction cycles

Start_conversion:

clr

START

set

START

; reset A/D

clr

START

; start A/D

Polling_EOC:

EOCB

; poll the ADCR register EOCB bit to detect end

; of A/D conversion

jmp

polling_EOC

; continue polling

mov

a,ADRL

; read low byte conversion result value

mov

adrl_buffer,a

; save result to user defined register

mov

a,ADRH

; read high byte conversion result value

mov

adrh_buffer,a

; save result to user defined register

jmp

start_conversion

; start next A/D conversion

Example: using the interrupt method to detect the end of conversion

clr

EADI

; disable ADC interrupt

mov

a,00000001B

mov

ACSR,a

; select fSYS/8 as A/D clock and turn on ADONB bit

mov

a,00100000B

; setup ADCR register to configure Port PB0~PB3

; as A/D inputs

mov

ADCR,a

; and select AN0 to be connected to the A/D

; As the Port B channel bits have changed the

; following START signal(0-1-0) must be issued

;

Start_conversion:

clr

START

set

START

; reset A/D

clr

START

; start A/D

clr

ADF

; clear ADC interrupt request flag

set

EADI

; enable ADC interrupt

set

EMFI1

; enable multi-function 1 interrupt

set

EMI

; enable global interrupt

; ADC interrupt service routine

ADC_:

mov

acc_stack,a

; save ACC to user defined memory

a,STATUS

mov

status_stack,a

; save STATUS to user defined memory

mov

a,ADRL

; read low byte conversion result value

mov

adrl_buffer,a

; save result to user defined register

mov

a,ADRH

; read high byte conversion result value

mov

adrh_buffer,a

; save result to user defined register

EXIT__ISR:

mov

a,status_stack

mov

STATUS,a

; restore STATUS from user defined memory

mov

a,acc_stack

; restore ACC from user defined memory

clr

ADF

; clear ADC interrupt flag

reti

HT45R37 Datasheet(PDF) 37 Page - Holtek Semiconductor Inc

HT45R37 Datasheet(HTML) 37 Page - Holtek Semiconductor Inc

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