Microcontroller Usage

5.5 Microcontroller Usage

5.5.1 Microcontroller Peripheral Usage

5.5.1.1 High Resolution PWM (HRP)

The HRP controls the ballast half-bridge power stage. The module is configured for frequency mode (constant 50% duty cycle, variable frequency, deadtime). For setting up the module, the worksheet HRP_Setup in file DLB_Setup.xls can be used (see Reference [4]).

5.5.1.2 Pulse-Width Modulator (PWM)

The PWM modulator is used to generate the reference sine wave for PFC control by PWM signal. The PWM1 signal is used only in the discontinuous conduction mode HW variation to directly switch the PFC switch transistor. For service PWM reload interrupt the pwmISR() routine is used (see Figure 5-5).

5.5.1.3 Comparator Module (CM)

The comparator module is used to compare the reference sine wave signal for PFC control with the actual current value. The result is the control signal for the PFC power MOSFET transistor in the hysteresis current control mode HW version. In the DCM HW version the comparator output is used for switching off the PWM1 signal.

5.5.1.4 Timer Interface Module (TIM)

Since an internal oscillator is used and its features do not guarantee constant frequency, this module is used to automatically trim the internal oscillator to the base of frequency of the mains voltage supply (PLL). The timer counts the time between two zero input voltage detections (IRQ); the resulting timer content is compared to the expected value, and the trimming register is adjusted accordingly (see Figure 5-4).

5.5.1.5 External Interrupt (IRQ)

The external interrupt is active on pin IRQ. The interrupt procedure is used for trimming the internal oscillator and synchronizing the phase shift of the reference sine wave with the mains voltage. The IRQisr() routine is used to service the IRQ interrupt.

5.5.2 Program and Data Memory Usage

Table 5-1shows the memory that is used by the software. A significant part of the memory remains available.

Table 5-1. Memory Usage

Memory

Available on LB8

Used

 

 

 

ROM

8192 Bytes

3010 Bytes

 

 

 

RAM

128 Bytes

40 Bytes

 

 

 

Dimmable Light Ballast with Power Factor Correction, Rev. 1

Freescale Semiconductor

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Freescale Semiconductor M68HC08 Microcontroller Usage, Microcontroller Peripheral Usage, Program and Data Memory Usage
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M68HC08 specifications

Freescale Semiconductor, known for its innovative solutions in the field of embedded systems, developed the M68HC08 microcontroller family, which includes the MC68HC908QT2. This 8-bit microcontroller is engineered to meet the demands of diverse applications, including automotive, industrial, and consumer electronics.

The MC68HC908QT2 is designed around Freescale’s M68HC08 core, which is renowned for its efficient and reliable performance. This microcontroller integrates a powerful instruction set, enabling developers to create high-performance applications with relatively low power consumption. The device operates at a clock frequency of up to 3 MHz, which is adequate for various control tasks.

One of the key features of the MC68HC908QT2 is its memory architecture. It includes a 2 KB Flash memory for program storage, representing a significant advantage for developers requiring non-volatile memory. Additionally, it encompasses 128 bytes of EEPROM memory, allowing for data retention even after power loss. The microcontroller also has 256 bytes of RAM for efficient data manipulation during operation.

In terms of input/output capabilities, the MC68HC908QT2 supports a variety of interfacing options. The microcontroller features up to 20 general-purpose I/O pins for flexibility in connecting with peripheral devices. Additionally, it provides multiple analog-to-digital converters (ADC) and timers that facilitate efficient analog signal processing and precise control through timing functions.

The architecture of the MC68HC908QT2 also incorporates sophisticated on-chip peripherals, enhancing its functionality. These peripherals include PWM (Pulse Width Modulation) outputs, which are essential for applications requiring motor control and other precise duty cycle processes. The integrated watchdog timer ensures reliable operation by resetting the system in the event of an application failure.

Moreover, the MC68HC908QT2 is equipped with an efficient power management system, enabling operation in a low-power mode, ideal for battery-powered applications. This microcontroller is packaged in a compact 28-pin dual in-line package (DIP), making it suitable for space-constrained designs.

In summary, the Freescale Semiconductor MC68HC908QT2 microcontroller is distinguished by its robust performance, extensive memory options, and versatile I/O capabilities. Its advanced features, including built-in timers, ADC, and a power management system, make it an exceptional choice for developers seeking to implement reliable and efficient embedded solutions. With its comprehensive architecture, the MC68HC908QT2 remains a popular choice in the landscape of 8-bit microcontrollers.
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