Create precise time intervals with DS1087L and PIC18F57Q43

Clock Gen 2 Click is based on the DS1087, a 3.3V spread-spectrum EconOscillator from Analog Devices. This IC is factory-produced with a range of different master clock frequencies, ranging from 33.3 MHz, up to 66.6 MHz, with variable spread spectrum percentages. The IC on the Clock Gen 2 click has the master clock fixed to 66.6 MHz, allowing the frequency range from 260 kHz to 66.6 MHz. This IC uses the clock prescaler from 2 0 to 2 8 to achieve frequencies different from the master frequency. By selecting the spread-spectrum percentage, it is possible to avoid the generation of too much EMI, which otherwise might violate the FCC/IEC regulations. As mentioned, the internal clock frequency that the DS1087 generates is 66.6MHz. The master clock is frequency-modulated by the internal triangle wave generator. The main oscillator frequency can be dithered below the maximum frequency by a selectable ratio. A bit in the prescaler register determines the spread-spectrum dither range, which can be selected between 2% and 4%

under the main clock frequency. The IC pin labeled as SPRD is routed to the mikroBUS™ PWM pin. A logic HIGH level on this pin enables the spread-spectrum function. The DS1087LU is equipped with non-volatile memory locations (EEPROM) to store the content of all the configuration registers. Writing data to the configuration registers can be automatically mirrored to the EEPROM. This is controlled by the Write Control bit (WC). It allows automatically storing data to EEPROM after each register change (WC = 0, default) or storing the config data manually by issuing the WRITE EE command (WC = 1). This feature allows the configuration to be remembered between the POR (Power ON Reset) cycles. The output Enable (OE) pin allows the output clock to be turned off at the output pin. A logic HIGH level on this pin turns off the clock output. However, this will not turn off the internal master clock generator, so the IC will still drain the power necessary to work. To completely put the device in a power-down mode, another pin is

used: a logic LOW level on the PDN pin shuts down the master oscillator, draining less current from the power source. The OE pin is routed to the mikroBUS™ CS pin and is labeled as OE, while the PDN pin is routed to the RST pin of the mikroBUS™ and is labeled as PDN. These signals are synchronized with the internal master clock, preventing glitches at the output. The clock output signal is at the SMA connector on the Click board™. This connector protects the high-frequency clock signal and further reduces EMI. It also provides reliable contact with the least possible losses. The clock output signal amplitude is 2.4V, which makes this Click board™ usable with most 3.3V operated MCUs and other devices. The standardized I2C interface allows this Click board™ to be interfaced with a wide range of devices. I2C clock and data pins of the IC (SCL and SDA) are routed to the appropriate mikroBUS™ pins, allowing simple and reliable interfacing.

PIC18F57Q43 Curiosity Nano evaluation kit is a cutting-edge hardware platform designed to evaluate microcontrollers within the PIC18-Q43 family. Central to its design is the inclusion of the powerful PIC18F57Q43 microcontroller (MCU), offering advanced functionalities and robust performance. Key features of this evaluation kit include a yellow user LED and a responsive

mechanical user switch, providing seamless interaction and testing. The provision for a 32.768kHz crystal footprint ensures precision timing capabilities. With an onboard debugger boasting a green power and status LED, programming and debugging become intuitive and efficient. Further enhancing its utility is the Virtual serial port (CDC) and a debug GPIO channel (DGI

GPIO), offering extensive connectivity options. Powered via USB, this kit boasts an adjustable target voltage feature facilitated by the MIC5353 LDO regulator, ensuring stable operation with an output voltage ranging from 1.8V to 5.1V, with a maximum output current of 500mA, subject to ambient temperature and voltage constraints.