JAJSTE0 March 2024 LMK05318B-Q1
PRODUCTION DATA
The HW_SW_CTRL input pin selects the device start-up mode that determines the memory page (EEPROM) used to initialize the registers, the serial interface, and the logic pin functions at power-on reset. The initial register settings determine the frequency configuration of the device on start-up. After start-up, the device registers can be accessed through the serial interface for device monitoring and programming, and the logic pins function as defined by the selected mode.
HW_SW_CTRL INPUT LEVEL(1) | START-UP MODE | MODE DESCRIPTION |
---|---|---|
0 | EEPROM + I2C (Soft pin mode) | Registers are initialized from EEPROM, and I2C interface is enabled. Logic pins:
|
Float (VIM) | EEPROM + SPI (Soft pin mode) | Registers are initialized from EEPROM, and SPI is enabled. Logic pins:
|
1 | Unused | For TI internal testing only. |
To verify proper start-up into EEPROM + SPI Mode, the HW_SW_CTRL, STATUS0, and STATUS1 pins must all be floating or biased to VIM (0.8V typical) before the PDN pin is pulled high. These three pins momentarily operate as 3-level inputs and get sampled at the low-to-high transition of PDN to determine the device start-up mode during POR. If any of these pins are connected to a system host (MCU or FPGA), TI recommends using external biasing resistors on each pin (10kΩ pullup to 3.3V with 3.3kΩ pulldown to GND) to set the inputs to VIM during POR. After power up, the STATUS pins can operate as LVCMOS outputs to overdrive the external resistor bias for normal status operation.