SNAS841 October 2023 LMK04714-Q1
PRODUCTION DATA
When CLKin_SEL_AUTO_EN = 0 and CLKin_SEL_PIN_EN = 1, the active clock is selected by the CLKIN_SELx and STATUS_LD1 pins.
Configuring Pin Select Mode
The CLKin_SEL0_TYPE must be programmed to an input value for the CLKIN_SEL0 pin to function as an input for pin select mode.
The CLKin_SEL1_TYPE must be programmed to an input value for the CLKIN_SEL1 pin to function as an input for pin select mode.
The polarity of the clock input select pins can be inverted with the CLKin_SEL_PIN_POL bit.
Table 8-7 defines which input clock is active depending on the clock input select pins state. The CLKIN_SEL1, CLKIN_SEL0, and STATUS_LD1 pins must be set as input type. Any pin set to output will always report Low on the table below.
CLKIN_SEL0 Pin | CLKIN_SEL1 Pin | STATUS_LD1 Pin | Active Clock |
---|---|---|---|
Low | Low | Low | CLKIN0 |
Low | High | Low | CLKIN1 |
High | Low | High | CLKIN2 |
High | High | X | Holdover |
The pin select mode overrides the EN_CLKinX bits such that the CLKINx buffer operates even if CLKINx is disabled with EN_CLKinX = 0. To switch as fast as possible, keep the clock input buffers enabled (EN_CLKinX = 1) that could be switched to.