Peripheral special function register with soft-reset disable
A microcontroller has a plurality of peripherals, and at least one control bit, wherein the control bit controls a reset of at least one peripheral such that in a first mode any type of reset resets the at least one peripheral of said plurality of peripherals and in a second mode only a power supply reset resets the at least one peripheral.
1. A microcontroller comprising a plurality of peripherals wherein one of the peripherals is a digital to analog converter having an output coupled with an external pin of the microcontroller,
wherein the microcontroller is operable to be reset by a power supply reset and wherein the microcontroller is further operable to generate an internally generated reset signal, and wherein the digital to analog converter is configurable through a configuration register comprising at least one control bit,
wherein the control bit controls an operating mode of the digital to analog converter such that in a first operating mode, both the power supply reset signal and the internally generated reset signal reset the digital to analog converter and in a second operating mode only a power supply reset resets the digital to analog converter and wherein the digital to analog converter maintains an output voltage programmed though an associated special function register at the external pin.
2. The microcontroller according to claim 1 , wherein a reset signal applied to the digital to analog converter disables the function of the digital to analog converter.
3. The microcontroller according to claim 1 , wherein the at least one control bit in the special function register controls only a reset function of said at least one peripheral.
4. The microcontroller according to claim 1 , wherein the power supply reset encompasses a power out reset and a brown out reset.
5. The microcontroller according to claim 1 , wherein the at least one bit is reset only by a power supply reset.
6. The microcontroller according to claim 1 , wherein in the second mode a soft reset does not reset the digital to analog converter.
7. The microcontroller according to claim 1 , further comprising a flip-flop controlled by said at least one bit, wherein the flip-flop controls a multiplexer selecting a first type of reset signal or a second type of reset signal, wherein the second type of reset signal excludes soft resets.
8. A method for resetting a microcontroller comprising a plurality of peripherals wherein one of the peripherals is a digital to analog converter having an output coupled with an external pin of the microcontroller, the method comprising:
providing a power supply reset signal controlled by an external supply voltage;
providing an internally generated reset signal controlled by said microcontroller;
programming the analog to digital converter to generate an output voltage which is fed to an external pin of the microcontroller;
setting or clearing a control bit associated with the digital-to analog converter to select a first or second reset mode, wherein in the first reset mode the power supply reset signal or the internally generated reset signal resets the digital-to analog converter and in a second reset mode only a power supply reset resets the digital-to analog converter.
9. The method according to claim 8 , wherein resetting the peripheral disables the function of the digital-to analog converter.
10. The method according to claim 8 , wherein the control bit in the special function register controls only a reset function of said digital-to analog converter.
11. The method according to claim 8 , wherein the power supply reset encompasses a power out reset and a brown out reset.
12. The method according to claim 8 , wherein the control bit is reset only by a power supply reset.
13. The method according to claim 8 , wherein in the second mode a soft reset does not reset the digital-to analog converter.
14. The method according to claim 8 , further comprising selecting a reset signal by means of a multiplexer from a first type of reset signal and a second type of reset signal, wherein the second type of reset signal excludes soft resets.
15. A system comprising a microcontroller with a plurality of peripherals,
wherein the microcontroller is operable to be reset by a power supply reset and wherein the microcontroller is further operable to generate an internally generated reset signal, and at least one control bit,
wherein the control bit controls an operating mode of a peripheral digital-to analog converter such that in a first operating mode, both the power supply reset signal and the internally generated reset signal reset the digital-to analog converter and in a second operating mode only a power supply reset resets the digital-to analog converter,
wherein the digital to-analog converter generates an analog signal fed to an external pin of the microcontroller; and
a power supply receiving a voltage reference provided by the external pin.
16. The system according to claim 15 , further comprising a load coupled with the power supply.
17. The microcontroller according to claim 1 , wherein the internally generated reset signal is a software reset or a watchdog reset signal.
18. The method according to claims 8 , wherein the internally generated reset signal is a software reset or a watchdog reset signal.
19. The system according to claim 15 , wherein a reset signal applied to the digital to analog converter disables the function of the digital to analog converter.