Holtek HT66F002 - Page 107

Rev. 1.71 106 April 11, 2017 Rev. 1.71 107 April 11, 2017
HT66F002/HT66F0025/HT66F003/HT66F004
Cost-Effective A/D Flash MCU with EEPROM
HT66F002/HT66F0025/HT66F003/HT66F004
Cost-Effective A/D Flash MCU with EEPROM
Example: using the interrupt method to detect the end of conversion
clr ADE ; disable ADC interrupt
mov a,0BH
mov SADC1,a ; select f
SYS
/8 as A/D clock and switch off the bandgap reference voltage
set ENADC
mov a,03h ; setup PASR to congure pin AN0
mov PASR,a
mov a,20h
mov SADC0,a ; enable and connect AN0 channel to A/D converter
Start_conversion:
clr START ; high pulse on START bit to initiate conversion
set START ; reset A/D
clr START ; start A/D
clr ADF ; clear ADC interrupt request ag
set ADE ; enable ADC interrupt
set EMI ; enable global interrupt
:
:
; ADC interrupt service routine
ADC_ISR:
mov acc_stack,a ; save ACC to user dened memory
mov a,STATUS
mov status_stack,a ; save STATUS to user dened memory
:
:
mov a,SADOL ; read low byte conversion result value
mov SADOL_buffer,a ; save result to user dened register
mov a,SADOH ; read high byte conversion result value
mov SADOH_buffer,a ; save result to user dened register
:
:
EXIT_INT_ISR:
mov a,status_stack
mov STATUS,a ; restore STATUS from user dened memory
mov a,acc_stack ; restore ACC from user dened memory
reti