HT46R49 Holtek Semiconductor, HT46R49 Datasheet - Page 32

• Manufacturer Part Number: HT46R49
• Description: Cost-Effective A/D Type 8-Bit MCU
• Manufacturer: Holtek Semiconductor

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Example: using an interrupt method to detect the end of conversion for the HT46R46
Start_conversion:
; ADC interrupt service routine
ADC_ISR:
EXIT_INT_ISR:
Rev. 1.30
clr EADI
mov a,00000001B
mov ACSR,a
mov a,00100000B
mov ADCR,a
clr START
set START
clr START
clr ADF
set EADI
set EMI
mov acc_stack,a
mov a,STATUS
mov status_stack,a
mov a,ADR
mov adr_buffer,a
mov a,status_stack
mov STATUS,a
mov a,acc_stack
reti
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; disable ADC interrupt
; setup the ACSR register to select fSYS/8 as
; the A/D clock
; setup ADCR register to configure Port PB0~PB3
; as A/D inputs
; 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 within 10
; instruction cycles
; reset A/D
; start A/D
; clear ADC interrupt request flag
; enable ADC interrupt
; enable global interrupt
; save ACC to user defined memory
; save STATUS to user defined memory
; read conversion result value from the ADR
; register
; save result to user defined register
; restore STATUS from user defined memory
; restore ACC from user defined memory
HT46R46/C46/R47/C47/R48A/C48A/R49
32
June 5, 2008