摘要:
A fluorescent lamp light intensity dimming control generates a pulse width modulation (PWM) signal at about a fifty percent duty cycle and has very fine frequency change granularity to allow precise and smooth light dimming capabilities. Intermediate PWM signal frequencies between the frequencies that are normally generated from values in a period register of the PWM generator are provided with a variable frequency clock source to the PWM generator. Selection of each frequency from the plurality of frequencies available from the variable frequency clock source may be determined from a value stored in a variable frequency clock register. A microcontroller may be used to select appropriate frequencies for dimming control of the fluorescent lamp from the variable frequency clock source, and the period and duty cycle values used in generating the PWM signal at about a fifty percent duty cycle.
摘要:
A dual or triple access interface (e.g., hardware and software implementation) allows a CPU and at least one DMA peripheral, e.g., Universal Serial Bus (USB) DMA engine, to transfer data in and/or out of a common single port SRAM by negotiating access requests between the CPU and the DMA peripheral, and then subsequently forms memory cycles to the single port SRAM to satisfy both the CPU's and DMA peripheral's memory access throughput requirements. This allows the CPU and the at least one DMA peripheral to access a shared single port SRAM by time multiplexing granted accesses between, for example, two or three simultaneous memory access requests, thus eliminating the need for a dual port memory.
摘要:
A mixed signal device having an analog-to-digital converter (ADC) with offset and gain calibration using internal voltage references whereby the digital processor calibrates out offset and gain errors in the analog-to-digital converter by adjusting the analog input amplifier gain and offset or with software compensating the digital representations of the voltages measured. Two different known voltage values are used in determining the offset and gain adjustments needed to calibrate the ADC against the two know voltage values. The mixed signal device may further comprise a Bandgap voltage reference having an accurate known voltage value. Wherein the Bandgap voltage reference may be used for further offset and gain calibration of the ADC to produce substantially absolute voltage values.
摘要:
A special mode key match comparison module has N-storage elements and a special mode key match comparator. The N-storage elements accumulate a serial data stream, and then determine whether a digital device should operate in a normal user mode, in a public programming mode, or in a particular private test mode. To reduce the possibility of accidentally decoding a false test or programming mode, the data stream has a sufficiently large number of N-bits to substantially reduce the probability of a false decode. To further reduce the possibility of accidentally decoding a programming or test mode, the special mode key match comparison module may be reset if less or more than N-clocks are detected during the accumulation of the N-bit serial data stream. The special mode key match data patterns may represent a normal user mode, a public programming mode, and particular private manufacturer test modes.
摘要:
Memory space of a digital device may be configured for both instructions/data (op-code) and ECC or parity when required, otherwise the entire memory space may be configured for just the program instructions/data. A standard word width memory may be configured for ECC or non-ECC functionality, or parity or non-parity functionality, based upon a desired application. The last portion of the memory may be allocated for ECC or parity data rather then application code when an ECC or parity implementation is required. When an ECC or parity implementation is not required, the entire memory may be used for the application code. This allows a digital device and memory to be used in applications having different robustness (e.g., application code integrity) requirements without have to fabricate different digital devices.
摘要:
An integrated circuit device comprising a configurable reference clock output to a peripheral function connection of the integrated circuit device provides a system clock or a frequency divided clock from the system clock as a clock source to a peripheral function on a peripheral function connection of the integrated circuit device. The clock function may be used to generate all necessary clocks for a plurality of integrated circuit devices and may be able to supply a system clock or frequency divided clock from the system clock, either from an external clock oscillator source or from an internally generated system clock, with the option of using a crystal for more accuracy and greater frequency stability. The external clock and/or internal clock may be made available for peripheral devices even when internal logic of the integrated circuit device may be in a standby/sleep mode.
摘要:
A microcontroller may have at least a first and second output port coupled with external first and second pins, respectively, a programmable switching arrangement operable in a first mode to provide for a first and second output signal at the first and second pins, respectively, and in a second mode to provide for a first output signal at the first pin and an inverted first output signal at the second pin.
摘要:
A digital device has a USB interface module that supports selection between an internal USB transceiver of the digital device and an external USB transceiver. Selection of either the internal or external USB transceiver may be controlled with a bit in a control register or memory location. The external USB transceiver may be electrically isolated from the USB interface module and/or extended over longer distances then is available under the USB specification.
摘要:
A method, system and apparatus are provided for alternating instruction sets in central processing units. A microcontroller is provided with a configuration mechanism, such as a fuse that, depending upon the setting, determines which of multiple instruction sets (or multiple parts of a single instruction set) can be processed by the central processing unit. By changing the fuse setting the characteristics of the central processing unit, and thus the microcontroller as a whole, can be changed.
摘要:
A system for powering down configuration circuits to minimize power consumption has at least one first configuration circuit for configuring a peripheral module. A second configuration circuit is coupled to the peripheral module and to the at least one first configuration circuit. The second configuration circuit is used for enabling and disabling the peripheral module. The second configuration circuit is further used to power down the at least one first configuration circuit to minimize current consumption of the at least one first configuration circuit when the peripheral module is disabled.