SLAU847D October 2022 – May 2024 MSPM0L1105 , MSPM0L1106 , MSPM0L1227 , MSPM0L1228 , MSPM0L1228-Q1 , MSPM0L1303 , MSPM0L1304 , MSPM0L1304-Q1 , MSPM0L1305 , MSPM0L1305-Q1 , MSPM0L1306 , MSPM0L1306-Q1 , MSPM0L1343 , MSPM0L1344 , MSPM0L1345 , MSPM0L1346 , MSPM0L2227 , MSPM0L2228 , MSPM0L2228-Q1
The IOMUX manages the selection of which peripheral function is to be used on a digital IO. It also provides the controls for the output driver, input path, and the wakeup logic for wakeup from SHUTDOWN mode.
There are several digital IO types which can be included on a given device. Each digital IO type supports different features. Table 9-1 lists the features which are included with each IO type. See the device-specific data sheet for which IO type is used on a given package pin.
IO Structure | Inversion Control | Drive Strength Control | Hysteresis Control | Pullup Resistor | Pulldown Resistor | Wakeup Logic |
---|---|---|---|---|---|---|
Standard-drive | Y | Y | Y | |||
Standard-drive with wake | Y | Y | Y | Y | ||
High-drive | Y | Y | Y | Y | Y | |
High-speed | Y | Y | Y | Y | ||
5V tolerant open drain | Y | Y | Y | Y |
Please note that the IOMUX will not support the inversion control and pesudo-open drain (output-high translated to high-impedance) setting on the SPI POCI pins. Also the IOMUX will not support inversion control on the SPI SCLK pins connected on an HSIO pin.
Certain pins on a device will be digital only and will not have any analog functions connected to the pin. Other pins can have one or more analog functions connected to the pin in addition to the digital IO functions. Analog functions are never selected within the IOMUX; they are always configured within of the respective analog peripheral. Analog peripherals have no knowledge of, or interaction with, the IOMUX.
In general, when analog functionality is used on a pin which also has digital functions, the IOMUX configuration for that pin should be left in its default (high-Z) state so as to not interfere with the proper operation of the analog function. However, it is possible to have the IOMUX active on a pin when an analog peripheral is also interacting with the pin, provided that the application software ensures that there is not a conflict between the functions. For example, it is possible to have the pullup or pulldown resistor on an IO enabled at the same time that the ADC is running a conversion on the same IO. However, an invalid configuration would be enabling the output driver on an IO at the same time that an analog peripheral is driving the IO (for example, a DAC or OPA output). This would create an IO conflict.
Application software is responsible for ensuring that the IOMUX settings do not conflict with any analog peripheral functions which can be enabled on a shared pad.
The mixed-signal IO pin slice diagram for a full featured IO pin is shown in Figure 9-1. Not all pins will have analog functions, wake-up logic, drive strength control, and pullup or pulldown resistors available. See the device-specific data sheet for detailed information on what features are supported for a specific pin.
The initial state of the IOMUX pin slice for all digital IO after a BOOTRST is as follows: