Figure 3-1 shows pin assignments for the 64-pin QFN package.

Figure 3-1 QFN 64-Pin Assignments

3.1 Pin Attributes and Pin Multiplexing

The device makes extensive use of pin multiplexing to accommodate the large number of peripheral functions in the smallest possible package. To achieve this configuration, pin multiplexing is controlled using a combination of hardware configuration (at device reset) and register control.

The board and software designers are responsible for the proper pin multiplexing configuration. Hardware does not ensure that the proper pin multiplexing options are selected for the peripherals or interface mode used.

Table 3-1 describes the general pin attributes and presents an overview of pin multiplexing. All pin multiplexing options are configurable using the pin mux registers.

The following special considerations apply:

• All I/Os support drive strengths of 2, 4, and 6 mA. Drive strength is configurable individually for each pin.
• All I/Os support 10-µA pullups and pulldowns.
• These pulls are not active and all of the I/Os remain floating while the device is in Hibernate state.
• The VIO and V_BAT supply must be tied together at all times.
• All digital I/Os are nonfail-safe.

1. LPDS mode: The state of unused GPIOs in LPDS is input with 500 kΩ pulldown. For all used GPIOs , the user can enable internal pulls, which would hold them in a valid state.
2. Hibernate mode: The CC3200 device leaves the digital pins in a Hi-Z state without any internal pulls when the device enters hibernate state. This can cause glitches on output lines unless held at valid levels by external resistors.
3. To minimize leakage in some serial flash vendors during LPDS, TI recommends the user application always enable internal weak pulldowns on FLASH_SPI_DATA and FLASH_SPI_CLK pins.
4. This pin has dual functions: as a SOP[2] (device operation mode), and as an external TCXO enable. As a TXCO enable, the pin is an output on power up and driven logic high. During hibernate low-power mode, the pin is in a high impedance state but pulled down for SOP mode to disable TCXO. Because of SOP functionality, the pin must be used as output only.
5. Higher leakage current from the onboard serial flash can occur due to floating inputs when the device enters Hibernate mode. See reference schematics for recommended pull-up and pull-down resistors.
6. For details on proper use, see Section 3.2, Drive Strength and Reset States for Analog-Digital Multiplexed Pins.
7. This pin is one of three that must have a passive pullup or pulldown resistor on board to configure the chip hardware power-up mode. Because of this reason, if this pin is used for digital functions, it must be output only.
8. This pin is reserved for WLAN antenna selection, controlling an external RF switch that multiplexes the RF pin of the CC3200 device between two antennas. These pins should not be used for other functionalities in general.
9. Device firmware automatically enables the digital path during ROM boot.
10. Pin 45 is used by an internal DC-DC (ANA2_DCDC) and pin 52 is used by the RTC XTAL oscillator. These modules use automatic configuration sensing. Therefore, some board-level configuration is required to use pin 45 and pin 52 as digital pads (see Figure 3-2). Because the CC3200R device does not require ANA2_DCDC, the pin can always be used for digital functions. However, pin 47 must be shorted to the supply input. Typically, pin 52 is used for RTC XTAL in most applications. However, in some applications a 32.768-kHz square-wave clock might always be available onboard. In such cases, the XTAL can be removed to free up pin 52 for digital functions. The external clock must then be applied at pin 51. For the chip to automatically detect this configuration, a 100K pull-up resistor must be connected between pin 52 and the supply line. To prevent false detection, TI recommends using pin 52 for output-only functions.
11. VDD_FLASH must be shorted to V_supply.
12. To use the digital functions, RTC_XTAL_N must be pulled high to V_supply using 100-KΩ resistor.
13. This pin is shared by the ADC inputs and digital I/O pad cells. Important: The ADC inputs are tolerant up to 1.8 V. On the other hand, the digital pads can tolerate up to 3.6 V. Hence, care must be taken to prevent accidental damage to the ADC inputs. TI recommends that the output buffer(s) of the digital I/Os corresponding to the desired ADC channel be disabled first (that is, converted to high-impedance state), and thereafter the respective pass switches (S7, S8, S9, S10) should be enabled (see Section 3.2, Drive Strength and Reset States for Analog-Digital Multiplexed Pins).
14. Requires user configuration to enable the ADC channel analog switch. (The switch is off by default.) The digital I/O is always connected and must be made Hi-Z before enabling the ADC switch.

Figure 3-2 Board Configuration to Use Pins 45 and 52 as Digital Signals

3.2 Drive Strength and Reset States for Analog-Digital Multiplexed Pins

Table 3-4 describes the use, drive strength, and default state of these pins at first-time power up and reset (nRESET pulled low).

3.3 Pad State After Application of Power To Chip But Prior To Reset Release

When a stable power is applied to the CC3200 chip for the first time or when supply voltage is restored to the proper value following a prior period with supply voltage below 1.5 V, the level of the digital pads are undefined in the period starting from the release of nRESET and until DIG_DCDC powers up. This period is less than approximately 10 ms. During this period, pads can be internally pulled weakly in either direction. If a certain set of pins are required to have a definite value during this pre-reset period, an appropriate pullup or pulldown must be used at the board level. The recommended value of this external pull is 2.7 KΩ.