9.4.1 Device Start-Up Modes
The LMK05028 can start up in one of three device modes depending on the 3-level input level sampled on the HW_SW_CTRL pin during power-on reset (POR):
- HW_SW_CTRL = 0: EEPROM + I2C Mode (Soft pin mode)
- HW_SW_CTRL = VIM / Float: EEPROM + SPI Mode (Soft pin mode)
- HW_SW_CTRL = 1: ROM + I2C Mode (Hard pin mode)
The device start-up mode determines:
- The memory bank (EEPROM or ROM) used to initialize the register settings that sets the frequency configuration.
- The serial interface (I2C or SPI) used for register access.
- The logic pin functionality for device control and status.
After start-up, the I
2C or SPI interface is enabled for register access to monitor the device status and control (or reconfigure) the device if needed. The register map configurations are the same for I
2C and SPI.
Table 1 summarizes the device start-up mode and corresponding logic pin functionality.
Figure 55 shows the device power-on reset configuration sequence.