Conversion start-up of an analog-to-digital converter within an integrated circuit
An analog-to-digital converter is clocked by a converter clock signal. A first clock signal has a frequency multiple of the frequency of the converter clock signal. A timer, which is clocked with the rhythm of the first clock signal, has a timing period multiple of the period of the converter clock signal. A processor is configured to control the converter based on the timing signal delivered by the timer, and has a first operating mode in which it is further configured to clock the timer synchronously with the converter clock signal and to deliver based on the timing signal, a periodic first conversion control signal of the converter, having a period multiple of the period of the converter clock signal and a constant first phase difference with the converter clock signal.
1 . An integrated circuit, comprising:
at least one first analog-to-digital converter, of the integrated circuit, configured to be clocked by a converter clock signal having a first frequency and a first period;
a clock input, of the integrated circuit, configured to receive a first clock signal having a second frequency multiple of the first frequency of the converter clock signal;
a timer, of the integrated circuit, configured to clock with a rhythm of the first clock signal and having a second period multiple of the first period of the converter clock signal; and
a processor, of the integrated circuit, configured to control the at least one first analog-to-digital converter based on a timing signal delivered by the timer, wherein the processor has a first operating mode in which the processor is further configured to clock the timer synchronously with the converter clock signal, and to deliver, based on the timing signal, a first periodic conversion control signal to the at least one first analog-to-digital converter, the first periodic conversion control signal having a third period multiple of the first period of the converter clock signal and a first constant phase difference with the converter clock signal.
2 . The integrated circuit according to claim 1 , wherein:
the integrated circuit further comprises a control input configured to receive a conversion control external signal;
the processor is configured, in the first operating mode, in response to the conversion control external signal, to generate an edge of the periodic first conversion control signal each time the timer reaches a selected timing value; and
the at least one first analog-to-digital converter is configured to periodically start conversions after a fixed and constant first period after the edge of the periodic first conversion control signal.
3 . The integrated circuit according to claim 2 , wherein the processor is further configured to deliver the converter clock signal and a sync signal indicating a first time point of each period of the converter clock signal, wherein the first time point is identical for each period, and, in a presence of the conversion control external signal, to delay triggering of the timer until a next first time point.
4 . The integrated circuit according to claim 2 , wherein the processor is configured to select the selected timing value from among several predefined timing values.
5 . The integrated circuit according to claim 2 , wherein the timer is reset synchronously with the converter clock signal.
6 . The integrated circuit according to claim 1 , further comprising at least one second analog-to-digital converter that is clocked by the converter clock signal, and the processor is further configured, in the first operating mode, to deliver a second periodic conversion control signal having a fourth period multiple of the first period of the converter clock signal and a second constant phase difference with the converter clock signal.
7 . The integrated circuit according to claim 1 , wherein the processor has a second operating mode in which the processor is configured to clock the timer asynchronously with the converter clock signal.
8 . The integrated circuit according to claim 7 , further comprising a selection input configured to receive a selection signal, wherein the first and second operating modes of the processor are selectable by the selection signal.
9 . A microcontroller, comprising:
at least one first analog-to-digital converter configured to be clocked by a converter clock signal having a first frequency and a first period;
a clock input configured to receive a first clock signal having a second frequency multiple of the first frequency of the converter clock signal;
a timer configured to clock with a rhythm of the first clock signal and having a second period multiple of the first period of the converter clock signal; and
a processor configured to control the at least one first analog-to-digital converter based on a timing signal delivered by the timer, wherein the processor has a first operating mode in which the processor is further configured to clock the timer synchronously with the converter clock signal, and to deliver, based on the timing signal, a first periodic conversion control signal to the at least one first analog-to-digital converter, the first periodic conversion control signal having a third period multiple of the first period of the converter clock signal and a first constant phase difference with the converter clock signal.
10 . The microcontroller according to claim 9 , wherein:
the microcontroller further comprises a control input configured to receive a conversion control external signal;
the processor is configured, in the first operating mode, in response to the conversion control external signal, to generate an edge of the periodic first conversion control signal each time the timer reaches a selected timing value; and
the at least one first analog-to-digital converter is configured to periodically start conversions after a fixed and constant first period after the edge of the periodic first conversion control signal.
11 . The microcontroller according to claim 9 , further comprising at least one second analog-to-digital converter that is clocked by the converter clock signal, and the processor is further configured, in the first operating mode, to deliver a second periodic conversion control signal having a fourth period multiple of the first period of the converter clock signal and a second constant phase difference with the converter clock signal.
12 . The microcontroller according to claim 9 , wherein the processor has a second operating mode in which the processor is configured to clock the timer asynchronously with the converter clock signal.
13 . A method of operating an integrated circuit, the method comprising:
clocking, by a converter clock signal having a first frequency and a first period, at least one first analog-to-digital converter;
receiving, by a clock input, a first clock signal having a second frequency multiple of the first frequency of the converter clock signal;
clocking a timer with a rhythm of the first clock signal and with a second period multiple of the first period of the converter clock signal;
controlling, by a processor, the at least one first analog-to-digital converter based on a timing signal delivered by the timer;
operating, by the processor, in a first operating mode comprising:
clocking, by the processor, the timer synchronously with the converter clock signal; and
delivering, by the processor, based on the timing signal, a first periodic conversion control signal to the at least one first analog-to-digital converter, the first periodic conversion control signal having a third period multiple of the first period of the converter clock signal and a first constant phase difference with the converter clock signal.
14 . The method according to claim 13 , wherein:
receiving, by a control input of the integrated circuit, a conversion control external signal;
generating, by the processor in the first operating mode, in response to the conversion control external signal, an edge of the periodic first conversion control signal each time the timer reaches a selected timing value; and
periodically starting, by the at least one first analog-to-digital converter, conversions after a fixed and constant first period after the edge of the periodic first conversion control signal.
15 . The method according to claim 14 , further comprising, by the processor:
delivering the converter clock signal and a sync signal indicating a first time point of each period of the converter clock signal, the first time point being identical for each period; and
delaying, in a presence of the conversion control external signal, triggering of the timer until a next first time point.
16 . The method according to claim 14 , further comprising, by the processor, selecting the selected timing value from among several predefined timing values.
17 . The method according to claim 14 , further comprising resetting the timer synchronously with the converter clock signal.
18 . The method according to claim 13 , further comprising:
clocking, by the converter clock signal, at least one second analog-to-digital converter; and
delivering, by the processor, in the first operating mode, a second periodic conversion control signal having a fourth period multiple of the first period of the converter clock signal and a second constant phase difference with the converter clock signal.
19 . The method according to claim 13 , further comprising, by the processor, in a second operating mode, clocking the timer asynchronously with the converter clock signal.
20 . The method according to claim 19 , further comprising receiving, by a selection input, a selection signal, the first and second operating modes of the processor being selectable by the selection signal.