C868 Datasheet, PDF (53/82 Pages) Infineon Technologies AG – 8-Bit Single-Chip Microcontroller

C868
remaining hardware conversion to complete before beginning a software
conversion.
Conversion and sample time control
The conversion and sample times are programmed via the bit fields ADCTC and ADSTC
respectively of the register ADCON1. Bit field ADCTC (conversion time control) selects
the internal ADC clock - adc_clk. Bit field ADSTC (sample time control) selects the
sample time.
The total A/D conversion time is given by:
t_ADCC = 2/f_SYS + t_S + 8/adc_clk
[5]
The sample time t_S is configured in periods of the selected internal ADC clock. The table
below lists the possible combinations.
ADCTC
Clock
Divider
(TVC)
000 (default) 32
001
28
010
24
011
20
100
16
101
12
110
8
111
4
ADC Basic Clock
adc_clk
f_SYS / 32
f_SYS / 28
f_SYS / 24
f_SYS / 20
f_SYS / 16
f_SYS / 12
f_SYS / 8
f_SYS / 4
ADSTC
Sample Time t_S
(Periods of
adc_clk, STC)
000 (default) 2
001
4
010
6
011
8
100
10
101
12
110
14
111
16
Data Sheet
53
V 1.0, 2003-05