CC2541 Introduction

1.1. Characteristics

The CC2541 is a SOC chip solution from TI designed for BLE and dedicated 2.4GHz applications. The CC2541 integrates a high-performance RF transceiver with industry-standard 8051, in-system programming flash memory and 8KRAM, supporting 250kbps, 500 kbps, 1Mbps and 2 Mbps data rates, RF output power up to 0dBm, and excellent receive sensitivity (e.g., Sensitivity up to -94dBm at 1 Mbps). The CC2541 also has many powerful supporting functions and peripherals.

1.2. Application

With the development of the Internet of Things, smart BLE remote control has become a necessary product in life and industry. Both civilian and military applications use smart BLE for control. Due to the characteristics of CC2541, it is very suitable for ultra-low power systems. For example, BLE systems such as dedicated 2.4GHz systems and 2.4GHz Bluetooth Low Energy systems.

1.3. Description

TI's CC2541 comes in two different versions: the CC2541F128 with 128kB of flash memory and the CC2541F256 with 256kB of flash memory.

Regardless of version, the reference design is the same. This design plan is mainly explained based on TI's official BLE remote control design.

2.1. Introduction

The CC2541 Bluetooth Smart Remote Kit provides a reference platform for the development of low-power Bluetooth remote control applications. It is based on TI's industry-leading Bluetooth Low Energy devices and the development, test, debug and remote control applications required to evaluate the CC2541. The kit includes an advanced programmable remote control, 6-axis motion sensing (3-axis accelerometer and 3-axis gyroscope), USB adapter and debugger.

Advanced Remote USB Adapters are pre-programmed to hide in their respective roles and GATT profile HID reporting services, including keyboard, consumer control key and mouse reporting. The Bluetooth Low Energy software stack is included in the sample application.

Advanced Remote Control can connect directly to Bluetooth Smart devices that support Hidden GATT, such as Windows 8. The USB adapter can be used as a bridge and the interface device does not have Bluetooth Smart ready support, such as Windows 7.

The advanced remote control of the CC2541 is designed as a hidden peripheral (BLEslave), operating according to the specifications in the GATT profile. It comes pre-assembled in a plastic box with rubber buttons, battery compartment and hole for accessing the programming head.

The CC2541's USB dongle can be used to emulate any Bluetooth Low Energy behavior, but is typically used as a central device (BLE Master) and HID Master. The suite has a central role in the pre-installed firmware as a hidden service client for advanced remote control that emulates input data for sending and receiving human interface devices (USB HIDs) in a connected Windows, Linux or OSX computer. The CCdebug debugger's Flash software is available on a USB adapter as well as advanced remote control. It can also be used for debugging via IAR EmbeddedWorkbench software. The kit's RF board and IC are FCC certified and tested to meet ETSI/R & TTE temperatures of 0 to 35 °C.

2.2. Schematic design

2.2.1 Power circuit

Advanced remote control operation is powered by three 1.5V alkaline AAA batteries (LR03). 3.3V LDO (tps78330) low voltage conversion circuit from 4.5V to 3.3V.

2.2.2 RF circuit

Refer to the CC2541 typical application circuit diagram.

2.2.3 Peripheral control circuit

Peripheral hardware available on the motherboard includes a buzzer, gyroscope, accelerometer, and shift register for key scanning. As a SOC chip solution, CC2541 can extract all GPIOs for schematic and PCB design for secondary development. For example, the E104-BT01 series of Chengdu Yiyi Electronic Technology Co., Ltd. meets this requirement.