SBASAM0B March 2024 – November 2024 ADS127L18
PRODMIX
The ADC provides an internal oscillator to operate the ADC. Because of the clock jitter, the internal oscillator is recommended only for measurement of dc signals. Use an external clock for measurement of ac signals. In SPI mode, default operation is the internal oscillator and is changed to external clock by setting the CLK_SEL bit = 1b. In the hardware programming mode, external clock operation is the default. Because the internal oscillator is 25.6MHz fixed frequency, program the ADC clock divider according to the requirements of the selected speed mode.
When changing the clock mode from an external clock to the internal oscillator, maintain the external clock after changing the clock mode. Maintain the clock mode for at least four cycles after the SPI register write command that changed the clock mode. After the clock mode change, the ADC ignores the control inputs (the START and RESET pins) for a period of 150μs. This time period allows the internal oscillator to stabilize.