User Manual
762
Rev. 1.1
2019-03-18
TLE984xQX
Microcontroller with LIN and Power Switches for Automotive Applications
10-Bit Analog Digital Converter (ADC1)
which results in 144 A/D conversion cycles. The average measurement periodicity of channel n in A/D
conversion cycles is defined as
(24.2)
The timing of the analog MUX and the digital DEMUX is controlled by the channel controller accordingly. The
analog MUX with sample and hold stage needs one clock cycle for channel switching and the ADC consumes,
as default setting, 12 clock cycles for the sampling of the input voltage. The conversion time for a single
channel measurement value is 17 clock cycles.
The minimum measurement periodicity, which can be achieved, by enabling only channel 1 in the sequence
registers, depends on the ADC1_CLK frequency and is given by:
This following calculations include already the sampling time of ADC. If all programmable channels are
enabled, the maximum periodicity is calculated:
(24.3)
(24.4)
For a ADC1_CLK frequency of 24 MHz, the channel 1 is measured with min. 1.1 µs. The maximum update time
of channel 1 with 24 MHz clock frequency is 10 µs. As mentioned before, this is calculated with the assumption,
that all channels are enabled and channel1 is enabled in every sequence register. As a prerequisite for this
calculation we take
= 4 (sample period = 12 ADC1_CLK clock cycles).
[ ]
meas
m
m
T
n
SQ
⎟
⎠
⎞
⎜
⎝
⎛
∑
=
12
1
N
meas, n
=
T
meas_CH1_min
=
26
f
adc1_clk
T
meas_CH1_min
=
312
f
adc1_clk