SWRU543B January 2019 – June 2025 CC3230S , CC3230SF , CC3235MODS , CC3235MODSF , CC3235S , CC3235SF
The internal analog switches and muxes for the analog-digital pins must be configured correctly for proper device operation, and to avoid damaging the device. When a digital I/O pad cell is routed correctly to the package pin using these analog switches, the functional pin-mux must be configured to select the desired digital interface pin to be brought out of the chip. In other words, these pins require two levels of mux configuration.
The CC32xx ROM firmware automatically configures the analog switches and muxes for pins 29, 30, 45, 50, 52, and 53 as part of the chip initialization sequence, which occurs after exiting from global reset (nRESET pulled high from low), exiting from hibernate mode, or exiting from LPDS mode. The application code can directly use these six pins like any other digital pins.
The ADC inputs, on the other hand, can tolerate levels only up to 1.8 V. Application code must therefore enable the analog switches for one or more ADC inputs, after ensuring there are no other internal or external drivers on the pins that can go above 1.8 V. The output buffer, pullup, and pulldown should be disabled while ADC inputs are connected to the pins, to avoid damaging the device.
Table 16-4 describes the register bits used to configure the internal analog switches and muxes for the analog-digital pins.
Table 16-5 describes the default behavior and configurations required for some of the analog-digital multiplexed I/Os used for digital signals.
| Pin | Analog Mux Control Register and Bit | Write Values | Reset Value | Notes |
|---|---|---|---|---|
| 29 | Register: MEM_TOPMUXCTRL_IFORCE Address: 0x4402 E178 Bit [0] | 0: GPIO26 Digital path not enabled 1: GPIO26 Digital path enabled | 0 | ANTSEL1 (GPIO26) Device init firmware enables the digital path. No user configuration required for the analog mux. |
| 30 | Register: MEM_TOPMUXCTRL_IFORCE Address: 0x4402 E178 Bit [1] | 0: GPIO27 Digital path not enabled 1: GPIO27 Digital path enabled | 0 | ANTSEL2 (GPIO27) Device init firmware enables the digital path. No user configuration required for the analog mux. |
| 45 | Register: MEM_HIB_CONFIG Address: 0x4402 F850 Bit [19] | 0: Digital path not enabled 1: Digital path enabled | 0 | Device init firmware enables the digital path. No user configuration required for the analog mux. |
| 50 | Register: MEM_HIB_CONFIG Address: 0x4402 F850 Bit [17] | 0: Digital path not enabled 1: Digital path enabled | 0 | Device init firmware enables the digital path. No user configuration required for the analog mux. |
| 52 | Register: MEM_HIB_CONFIG Address: 0x4402 F850 Bit [16] | 0: Digital path not enabled 1: Digital path enabled | 0 | Device init firmware enables the digital path. No user configuration required for the analog mux. |
| 53 | Register: MEM_HIB_CONFIG Address: 0x4402 F850 Bit [18] | 0: Digital path not enabled 1: Digital path enabled | 0 | Device init firmware enables the digital path. No user configuration required for the analog mux. |
| 57 | Register: ADCSPARE1 Address: 0x4402 E8B8 Bit [1] | 0: ADC channel 0 path is not enabled 1: ADC channel 0 path is enabled | 0 | Digital I/O cell is always connected to this pin, and application software must make the digital I/O Hi-Z before enabling analog mux, to prevent damaging the device. |
| 58 | Register: ADCSPARE1 Address: 0x4402 E8B8 Bit [2] | 0: ADC channel 1 path is not enabled 1: ADC channel 1 path is enabled | 0 | Digital I/O cell is always connected to this pin, and application software must make the digital I/O Hi-Z before enabling analog mux, to prevent damaging the device. |
| 59 | Register: ADCSPARE1 Address: 0x4402 E8B8 Bit [3] | 0: ADC channel 2 path is not enabled 1: ADC channel 2 path is enabled | 0 | Digital I/O cell is always connected to this pin, and application software must make the digital I/O Hi-Z before enabling analog mux, to prevent damaging the device. |
| 60 | Register: ADCSPARE1 Address: 0x4402 E8B8 Bit [4] | 0: ADC channel 3 path is not enabled 1: ADC channel 3 path is enabled | 0 | Digital I/O cell is always connected to this pin, and application software must make the digital I/O Hi-Z before enabling analog mux, to prevent damaging the device. |
| Pin | Board Level Configuration and Usage | Default State At First Powerup or Forced Reset | State After Disabling Analog Path (in ACTIVE, LPDS, HIB power modes) |
|---|---|---|---|
| 29 | Connected to enable pin of RF switch (ANTSEL1). Other usage not recommended. | Analog is isolated. Digital I/O cell is also isolated. | Determined by the I/O cell state, like other digital I/Os. |
| 30 | Connected to enable pin of RF switch (ANTSEL2). Other usage not recommended. | Analog is isolated. Digital I/O cell is also isolated. | Determined by the I/O cell state, like other digital I/Os. |
| 45 | VDD_ANA2 (pin 47) must be shorted to input supply rail. Otherwise this pin will be driven by the ANA2 DCDC | Analog is isolated. Digital I/O cell is also isolated. | Determined by the I/O cell state, like other digital I/Os. |
| 50 | Generic Input/Output | Analog is isolated. Digital I/O cell is also isolated. | Determined by the I/O cell state, like other digital I/Os. |
| 52 | This pin must have an external pullup of 100K to supply rail. This pin must be used for output only signals. | Analog is isolated. Digital I/O cell is also isolated. | Determined by the I/O cell state, like other digital I/Os. |
| 53 | Generic Input/Output | Analog is isolated. Digital I/O cell is also isolated. | Determined by the I/O cell state, like other digital I/Os. |
| 57 | Analog signal (1.8-V absolute max. 1.46-V full scale) | ADC is isolated. Digital I/O cell is directly connected but Hi-Z. | Determined by the I/O cell state, like other digital I/Os. |
| 58 | Analog signal (1.8-V absolute max. 1.46-V full scale) | ADC is isolated. Digital I/O cell is directly connected but Hi-Z. | Determined by the I/O cell state, like other digital I/Os. |
| 59 | Analog signal (1.8-V absolute max. 1.46-V full scale) | ADC is isolated. Digital I/O cell is directly connected but Hi-Z. | Determined by the I/O cell state, like other digital I/Os. |
| 60 | Analog signal (1.8-V absolute max. 1.46-V full scale) | ADC is isolated. Digital I/O cell is directly connected but Hi-Z. | Determined by the I/O cell state, like other digital I/Os. |