divider units. The chip must be configured using its serial I2C interface. R1 and R2 are 1K pullup
resistors required for the I2C bus.
For high frequency stability, a 0.25ppm TCXO is used (the same TCXO as used in QCX-series
CW transceivers and QDX digital transceivers).
The Si5351A does not preserve its configuration registers through a power cycle. To provide
persistent storage of parameters, the microcontroller needs to retain the configuration parameters
in non-volatile storage. STM32-series microcontrollers do not have onboard EEPROM and to save
parts count and board area, no additional I2C EEPROM chip has been used in ProgRock2.
Instead, the top 1KByte sector of the Flash memory of the STM32 is used as a non-volatile
storage area for the configuration parameters.
PCB Trace diagram:
PCB Trace diagram with groundplanes:
ProgRock2 manual 1.00b
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