The SimpleLink™ CC3100 and CC3200 devices are Wi-Fi® and networking devices that provide a comprehensive networking solution for low-cost and low-power microcontrollers (MCU) using a thin driver and simple API set.

Each product with an embedded CC3100 or CC3200 device onboard must also have a serial flash device connected. The serial flash must be formatted, and at a minimum programmed with the Service Pack, which contains necessary software updates and additional features. For the CC3200, a binary image running on the internal MCU processor must also be programmed.

There are several options for serial flash programming, as follows:

• UniFlash – a PC-based utility offering image creation and programming. Content is programmed using the UART.
• Industrial flash programmer – flashes a complete image prepared with UniFlash directly to the serial flash. Can be applied when no SimpleLink device is attached to the serial flash. Content is programmed using the serial flash SPI lines.
• Over-the-air programming – the serial flash must be formatted in advance. Content is delivered through a network connection.

This application note describes in details additional options that leverage all the features UniFlash has to offer, but without the necessary connected PC. This option is referred to as Embedded Programming. To achieve embedded programming, bootloader protocol implemented over UART is described in detail.

The following sections describe the setup, bootloader protocol, and procedure of the embedded programming feature.

Several schemes can leverage full image programming over the UART, as follows.

• Embedded programming in production line – there are setups on the production line that do not include the PC. Instead, programmable devices such as the MCU, DSP, or FPGA are used.
• Main external processor (other than the CC3200 MCU) – in many cases, CC3100 and CC3200 devices are just another component in the device enabling network communication. Such devices have main processors that usually control and schedule everything in the system. These cores must have the ability to upgrade and program CC3100 or CC3200 peripherals.

The UART interface must be connected between the CC3100 or CC3200 device and the main processor. Only two pins are required, UART TX and UART RX. Flow control is not required.

The common configuration that applies to all chipsets follows:

• Baud rate of 921600 bps
• 8 bits
• No parity
• 1 stop bit

In addition, the nHib/nReset pin is required and it must be have the ability to be temporarily pulled to GND during a reset to make the device go into bootloader mode.

For the CC3200 device, an additional SOP1 pin must be pulled up during the device reset to make the device go into bootloader mode.

Figure 3-1 CC3200 and CC3200 QFN Programming Setup

The CC3100 and CC3200 bootloader protocol is a simple command-response protocol. The protocol is based on the protocol used by the Stellaris® LM Flash Programmer. The commands are serially executed and there are no unsolicited events during the bootloader phase.

Table 4-1 provides the general message format.

The length includes all fields except the checksum (including the Length field itself), so in general:

Checksum is a simple hexadecimal addition of the Opcode and Data fields. Checksum is then clipped to occupy the least significant byte only.

Table 4-2 lists all the commands and responses of the bootloader protocol.

Table 4-3 lists the Get Status command.

Table 4-4 lists the Get Storage List command.

Table 4-5 lists the Raw Storage Write command.

Table 4-6 lists the Get Version Info command.

Table 4-7 lists the Raw Storage Erase command.