Create precise time intervals with DS1087L and STM32F413ZH

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.

Nucleo-144 with STM32F413ZH MCU board offers an accessible and adaptable avenue for users to explore new ideas and construct prototypes. It allows users to tailor their experience by selecting from a range of performance and power consumption features offered by the STM32 microcontroller. With compatible boards, the

internal or external SMPS dramatically decreases power usage in Run mode. Including the ST Zio connector, expanding ARDUINO Uno V3 connectivity, and ST morpho headers facilitate easy expansion of the Nucleo open development platform. The integrated ST-LINK debugger/programmer enhances convenience by

eliminating the need for a separate probe. Moreover, the board is accompanied by comprehensive free software libraries and examples within the STM32Cube MCU Package, further enhancing its utility and value.