HT46R62 Holtek Semiconductor Inc., HT46R62 Datasheet - Page 22

• Manufacturer Part Number: HT46R62
• Description: Ht46r62/ht46c62 -- A/d With Lcd Type 8-bit Mcu
• Manufacturer: Holtek Semiconductor Inc.

Note:
The following programming example illustrates how to setup and implement an A/D conversion. The method of poll-
ing the EOCB bit in the ADCR register is used to detect when the conversion cycle is complete.
Example: using EOCB Polling Method to detect end of conversion
Start_conversion:
Polling_EOC:
Rev. 1.70
PCR2
mov
mov
mov
mov
clr
set
clr
sz
jmp
mov
mov
ADRH (25H)
ADRL (24H)
0
0
0
0
1
1
1
1
Register
ACS2
D0~D8 is A/D conversion result data bit LSB~MSB.
0
0
0
0
1
1
1
1
a,00000001B
ACSR,a
a,00100000B
ADCR,a
:
:
:
START
START
START
EOCB
polling_EOC
a,ADRH
adrh_buffer,a
PCR1
0
0
1
1
0
0
1
1
PCR0
Bit7
0
1
0
1
0
1
0
1
D0
D8
ACS1
0
0
1
1
0
0
1
1
; setup the ACSR register to select f
; 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
; poll the ADCR register EOCB bit to detect end of A/D conversion
; continue polling
; read conversion result high byte value from the ADRH register
; save result to user defined memory
7
Bit6
D7
ADRL (24H), ADRH (25H) Register
Analog Input Channel Selection
6
Port B Configuration
Bit5
D6
ACS0
0
1
0
1
0
1
0
1
PB5
PB5
PB5
PB5
PB5
PB5
AN5
AN5
22
5
Bit4
D5
PB4
PB4
PB4
PB4
PB4
AN4
AN4
AN4
4
SYS
Bit3
D4
/8 as the A/D clock
AN3
AN3
AN3
AN3
PB3
PB3
PB3
PB3
3
Analog Channel
Bit2
D3
HT46R62/HT46C62
PB2
PB2
PB2
AN2
AN2
AN2
AN2
AN2
AN0
AN1
AN2
AN3
AN4
AN5
AN5
AN5
2
Bit1
D2
February 14, 2006
PB1
PB1
AN1
AN1
AN1
AN1
AN1
AN1
1
Bit0
PB0
AN0
AN0
AN0
AN0
AN0
AN0
AN0
D1
0