HT46R4A Holtek Semiconductor, HT46R4A Datasheet - Page 29

• Manufacturer Part Number: HT46R4A
• Description: Cost-Effective A/D Type 8-Bit MCU
• Manufacturer: Holtek Semiconductor

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Start_conversion:
Polling_EOC:
Example: using an interrupt method to detect the end of conversion
Start_conversion:
; ADC interrupt service routine
ADC_ISR:
EXIT_INT_ISR:
Rev. 1.00
clr
set
clr
sz
jmp
mov
mov
mov
mov
jmp
clr
mov
mov
mov
clr
set
clr
clr
set
set
mov
mov
mov
mov
mov
mov
mov
mov
mov
mov
reti
START
START
START
EOCB
polling_EOC
a,ADRL
adr_low_buffer,a
a,ADRH
adr_high_buffer,a ; save result to user defined memory
:
start_conversion
EADI
a,00000001B
ACSR,a
a,00100000B
ADCR,a
:
:
START
START
START
ADF
EADI
EMI
:
:
:
acc_stack,a
a,STATUS
status_stack,a
:
:
a,ADRL
adr_low_buffer,a
a,ADRH
adr_high_buffer,a ; save result to user defined memory
:
a,status_stack
STATUS,a
a,acc_stack
; reset A/D
; start A/D
; poll the ADCR register EOCB bit to detect end
; of A/D conversion
; continue polling
; read low byte conversion value
; save result to user defined memory
; read high byte conversion value
; start next A/D conversion
; 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 low byte conversion value
; save result to user defined register
; read high byte conversion value
; restore STATUS from user defined memory
; restore ACC from user defined memory
29
November 28, 2007
HT46R4A