SWAS034 February 2017 CC3120
The CC3120R Wi-Fi Internet-on-a-chip contains a dedicated ARM MCU that offloads many of the networking activities from the host MCU. The device includes an 802.11b/g/n radio, baseband, and MAC with a powerful crypto engine for a fast, secure WLAN and Internet connections with 256-bit encryption. The CC3120R device supports station, AP, and Wi-Fi Direct modes. The device also supports WPA2 personal and enterprise security and WPS 2.0. The Wi-Fi network processor includes an embedded IPv6 and IPv4 TCP/IP stack.
Figure 5-1 shows the functional block diagram of the CC3120R SimpleLink Wi-Fi solution.
The WLAN features are as follows:
802.11n is supported only in Wi-Fi station, Wi-Fi direct, and P2P client mode
The Network Stack features are as follows:
Not all APIs are 100% BSD compliant. Not all BSD APIs are supported.
Table 5-1 summarizes the NWP features.
|Wi-Fi standards||802.11b/g/n station|
|802.11b/g AP supporting up to four stations|
|Wi-Fi Direct client and group owner|
|Wi-Fi||Channels 1 to 13|
|Wi-Fi security||WEP, WPA/WPA2 PSK, WPA2 enterprise (802.1x)|
|Wi-Fi provisioning||SmartConfig technology, Wi-Fi protected setup (WPS2), AP mode with internal HTTP/HTTPS web server|
|IP addressing||Static IP, LLA, DHCPv4, DHCPv6 (Stateful) with DAD and stateless auto configuration|
|Cross layer||ARP, ICMPv4, IGMP, ICMPv6, MLD, NDP|
|Network applications and utilities||Ping|
|HTTP/HTTPS web server|
|Trusted root-certificate catalog|
|TI root-of-trust public key|
|Power management||Enhanced power policy management uses 802.11 power save and deep sleep power modes|
|Programmable RX Filters with Events trigger mechanism including WoWLAN|
|Recovery mechanism – Restore to factory default|
The SimpleLink Wi-Fi CC3120R Internet-on-a-chip device enhances the security capabilities available for development of IoT devices, while completely offloading these activities from the MCU to the networking subsystem. The security capabilities include the following key features:
Wi-Fi and Internet Security:
Code and Data Security:
The CC3120R power-management subsystem contains DC-DC converters to accommodate the different voltage or current requirements of the system.
The CC3120R device is a single-chip WLAN radio solution used on an embedded system with a wide-voltage supply range. The internal power management, including DC-DC converters and LDOs, generates all of the voltages required for the device to operate from a wide variety of input sources. For maximum flexibility, the device can operate in the modes described in Section 5.4.1 and Section 5.4.2.
In the wide-voltage battery connection, the device is powered directly by the battery or preregulated 3.3-V supply. All other voltages required to operate the device are generated internally by the DC-DC converters. This scheme supports wide-voltage operation from 2.1 to 3.6 V and is thus the most common mode for the device.
The preregulated 1.85-V mode of operation applies an external regulated 1.85 V directly at pins 10, 25, 33, 36, 37, 39, 44, 48, and 54 of the device. The VBAT and the VIO are also connected to the 1.85-V supply. This mode provides the lowest BOM count version in which inductors used for PA DC-DC and ANA1 DC-DC (2.2 and 1 µH) and a capacitor (22 µF) can be avoided.
In the preregulated 1.85-V mode, the regulator providing the 1.85 V must have the following characteristics:
The regulator must be placed as close as possible to the device so that the IR drop to the device is very low.
This section describes the low-power modes supported by the device to optimize battery life.
The low-power deep-sleep (LPDS) mode is an energy-efficient and transparent sleep mode that is entered automatically during periods of inactivity based on internal power optimization algorithms. The device can wake up in less than 3 ms from the internal timer or from any incoming host command. Typical battery drain in this mode is 115 µA. During LPDS mode, the device retains the software state and certain configuration information. The operation is transparent to the external host; thus, no additional handshake is required to enter or exit LPDS mode.
The hibernate mode is the lowest power mode in which all of the digital logic is power-gated. Only a small section of the logic powered directly by the main input supply is retained. The RTC is kept running and the device wakes up once the nHIB line is asserted by the host driver. The wake-up time is longer than LPDS mode at approximately 50 ms.
Wake-up time can be extended depending on the service-pack size.
The shutdown mode is the lowest power-mode system-wise. All device logics are off, including the real-time clock (RTC). The wake-up time in this mode is longer than hibernate at approximately 1.1 s.
The CC3120R device maintains a proprietary file system on the sFLASH. The CC3120R file system stores the service pack file, system files, configuration files, certificate files, web page files, and user files. By using a format command through the API, users can provide the total size allocated for the file system. The starting address of the file system cannot be set and is always at the beginning of the sFLASH. The applications microcontroller must access the sFLASH memory area allocated to the file system directly through the CC3120R file system. The applications microcontroller must not access the sFLASH memory area directly.
The file system manages the allocation of sFLASH blocks for stored files according to download order, which means that the location of a specific file is not fixed in all systems. Files are stored on sFLASH using human-readable filenames rather than file IDs. The file system API works using plain text, and file encryption and decryption is invisible to the user. Encrypted files can be accessed only through the file system.
All file types can have a maximum of 100 supported files in the file system. All files are stored in 4-KB blocks and thus use a minimum of 4KB of flash space. Fail-safe files require twice the original size and use a minimum of 8KB. Encrypted files are counted as fail-safe in terms of space. The maximum file size is 1MB.
Table 5-2 lists the minimum required memory consumption under the following assumptions:
|File system allocation table||20|
|System and configuration files||256|
|Gang image size||256|
|Minimal flash size||8MBit|
|Recommended flash size||16MBit|
The maximum supported sFLASH size is 32MB (256Mb). Please refer to Using Serial Flash on CC3120/CC3220 SimpleLink™ Wi-Fi® and Internet-of-Things Devices.
The device has an internal recovery mechanism that allows rolling back the file system to its predefined factory image or restoring the factory default parameters of the device. The factory image is kept in a separate sector on the sFLASH in a secure manner and cannot be accessed from the host processor. The following restore modes are supported:
The restore process is performed by pulling or forcing SOP[2:0] = 110 pins and toggling the nRESET pin from low to high.
The process is fail-safe and resumes operation if a power failure occurs before the restore is finished. The restore process typically takes about 8 seconds, depending on the attributes of the serial flash vendor.