# US 2008/0186073 A1 · Determining a Time Base for a Microcontroller > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2008/0186073 A1 - Document ID: US20080186073A1 - Status: Published application - Kind: A1 - Application number: 11/912,087 - Filed: 2006-03-18 - Published: 2008-08-07 - Earliest claimed: 2005-04-20 - Assignees: Braun GmbH - Inventors: Michael Franke - Web page: https://patentgrep.com/patent/US20080186073A1 ## CPC - G04F 1/005: {using electronic timing, e.g. counting means (pulse time delay arrangements H03K5/13; modifications of electronic switches for introducing a time delay before switching H03K17/28)} - G06F 1/04: Generating or distributing clock signals or signals derived directly therefrom - H03K 5/145: by the use of resonant circuits - G04F: TIME-INTERVAL MEASURING (measuring pulse characteristics G01R, e.g. G01R29/02; in radar or like systems G01S) - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M) ## Abstract The invention relates to a method for producing a time base for a microcontroller and a simple circuit arrangement therefor, which comprises an RC-element having a specific time constant, said element being connected to a connection of the microcontroller. According to said method, the capacitor of the RC element is charged to an initial voltage in a first step, then in a second step, the number of timed impulses is counted until the voltage on the capacitor falls below the initial voltage to a determined percentage of the initial voltage or a voltage threshold value, and then in a third step, the counted number of timed impulses is used as a time base. ## Claims ### Claim at position 1 1-9. (canceled) ### Claim 10 A method for producing a time base for a microcontroller with a clock generator for a clock signal and an RC-element with a certain time constant, the method comprising: charging a capacitor of the RC-element to a starting voltage; counting a number of pulses of the clock signal as the voltage on the capacitor of the RC-element falls to a predetermined percentage of the starting voltage or to a predetermined threshold voltage; and then determining the time base as a function of the counted number of clock pulses. ### Claim 11 (depends on 10) The method of claim 10, wherein the predetermined voltage threshold is defined by an interrupt triggering threshold of the microcontroller. ### Claim 12 (depends on 11) The method of claim 11, further comprising: recharging the capacitor of the RC-element to the starting voltage; causing the microcontroller to initiate a power-saving mode; waiting until the voltage across the capacitor falls to the predetermined percentage of the starting voltage or the predetermined voltage threshold; and then causing the microcontroller to exit the power-saving mode. ### Claim 13 (depends on 12) The method of claim 12, further comprising incrementing a time counter by an amount corresponding to the determined time base. ### Claim 14 (depends on 13) The method of claim 13, repeated multiple times in sequence. ### Claim 15 A time base determination circuit for a microcontroller with an internal clock generator that generates a clock signal, the circuit comprising: an external RC-element, including a capacitor and having a certain time constant; the RC-element electrically connected to the microcontroller wherein the capacitor is charged to a starting voltage, a number of pulses of the clock signal is counted as the voltage across the capacitor of the RC-element falls to a predetermined percentage of the starting voltage or to a predetermined threshold voltage, and the time base is determined as a function of the counted number of clock pulses. ### Claim 16 (depends on 15) The circuit of claim 15, wherein the RC-element is electrically connected to a connection of the microcontroller, and the connection is both an output and an input of the microcontroller. ### Claim 17 (depends on 15) The circuit of claim 15, wherein the capacitor of the RC-element is charged by the microcontroller. ### Claim 18 (depends on 15) The circuit of claim 15, wherein the voltage across the capacitor of the RC-element is measured by the microcontroller. ### Claim 19 A time base determination circuit for a microcontroller with an internal clock generator that generates a clock signal and a non-volatile memory, the circuit comprising: an RC-element, including a capacitor and having a certain time constant; the RC-element electrically connected to the microcontroller wherein the capacitor is charged to a starting voltage, a number of pulses of the clock signal is counted as the voltage across the capacitor of the RC-element falls to a predetermined percentage of the starting voltage or to a predetermined threshold voltage, the counted number of clock pulses is stored in the non-volatile memory, and the time base is determined as a function of the counted number of clock pulses. ### Claim 20 (depends on 19) The circuit of claim 19, wherein the RC-element is external to the microcontroller and is connected to an input/output connection of the microcontroller. ### Claim 21 (depends on 19) The circuit of claim 19, wherein the RC-element is external to the microcontroller and is connected to an input connection and an output connection of the microcontroller. ### Claim 22 (depends on 19) The circuit of claim 19, further comprising an A/D converter for measuring the voltage across the capacitor of the RC-element. ### Claim 23 A time base determination circuit for a microcontroller with an internal clock generator, the circuit comprising: an RC-element, including a capacitor and having a certain time constant; and an internal A/D converter for measuring a voltage applied to the RC-element; the RC-element electrically connected to the A/D converter and the microcontroller wherein the capacitor is charged to a starting voltage, a number of clock pulses generated by the clock generator is counted as the voltage across the capacitor of the RC-element falls to a predetermined percentage of the starting voltage or to a predetermined threshold voltage, and the time base is determined as a function of the number of clock pulses counted. ### Claim 24 (depends on 23) The circuit of claim 23, wherein the RC-element is internal to the microcontroller. ### Claim 25 (depends on 23) The circuit of claim 23, wherein the RC-element is external to the microcontroller and is connected to an input connection and an output connection of the microcontroller. ### Claim 26 (depends on 25) The circuit of claim 25, wherein the capacitor of the RC-element is charged by the microcontroller. ### Claim 27 (depends on 23) The circuit arrangement of claim 23, further comprising a time counter, wherein the capacitor of the RC-element is recharged to the starting voltage, the microcontroller is transferred into a power-saving mode until the voltage across the capacitor falls to the predetermined threshold voltage, the microcontroller exits the power-saving mode, and the time counter is incremented by an amount corresponding to the time base. ### Claim 28 A time base determination circuit for a microcontroller with an internal clock generator, the circuit comprising: an RC-element, including a capacitor and having a certain time constant; and an internal A/D converter for measuring a voltage across the capacitor of the RC-element; the RC-dement electrically connected to the A/D converter and the microcontroller wherein the capacitor is charged to a starting voltage, a number of clock pulses generated by the clock generator is counted as the voltage across the capacitor of the RC-element falls to a predetermined threshold voltage, the number of clock pulses counted is stored in a non-volatile memory, the capacitor is recharged to the starting voltage, the clock generator of the microcontroller is switched off, and when the voltage across the capacitor fells to the predetermined threshold voltage, the clock generator is switched on. ### Claim 29 (depends on 28) The circuit arrangement of claim 28, further comprising a time counter having a value, wherein the value is incremented by the number of clock pulses stored in the non-volatile memory for each of a plurality of transitions of the clock generator from off to on.