The STSW-STC is turnkey software for the STNRG328S product, distributed as a binary file to install in the STNRG328S to fit STC/HSTC tolpologies for server applications in the whole range of conversion ratios from 2:1 to 10:1 from a 48 V supply bus.
The STNRG328S provides UART communication for external programming of parameters and STC/HSTC control.
STSW-STC firmware supports both types of boards: U2J discrete components and ZCD/HTSC, where ZCD means Zero Current Detection.
At the power-on, it recognizes the board configuration setting the right parameters, controls PWMs frequency, checks the fault conditions, triggers the protections and initializes the peripherals of the device, implements the SMEDs (State Machine Events Driven), communication on I2C; for the HTSC configuration it defines the matrix ZCD in the RAM&E2PROM memories containing the frequencies and deadtimes selected by the input voltage.
It also defines the functions of writing, reading and search algorithm in ZCD tables in order to apply the correct frequency and deadtime according to the input voltage; implements the software requests depending on the board configuration selected; defines the programmable parameters and structures stored in NVM memory; contains the variables to access the registers of the device; schedules the ADC sequence and processes the relative operations, sets the timeout of each system state and reports an error on I2C in case of error, collects 7 samples for each ADC conversion sequence; handles the data bytes of PMBUS command from/to I2C; detects if the pin ENABLES is high or low to turn on or off the device, detects the events corresponding to undervoltage condition, Vdrive undervoltage and overvoltage condition for triggering the protections.