Design based on TI CC2541 BLE remote control

A briefintroduction to CC2541

1.1. Features

The CC2541 is a SOC chip solution from TI that is specifically designed for BLEand dedicated 2.4GHz applications. The CC2541 integrates a high-performance RFtransceiver with an industry-standard 8051, in-system programmed flash and 8KRAM, supports 250kbps, 500 kbps, 1Mbps and 2 Mbps data rates, RF output powerup to 0dBm, and excellent receive sensitivity (For example, the sensitivity canreach -94dBm at 1 Mbps). The CC2541 also has many powerful support features andperipherals.

1.2. Application

With the development of the Internet of Things, intelligent BLE remote controlhas become a must-have product in life and industry. Both civil and militaryuse intelligent BLE to control. For the characteristics of the CC2541, it isideal for systems with ultra-low power consumption. For example, BLE systemssuch as dedicated 2.4GHz systems and 2.4GHz Bluetooth low energy systems.
1.3. Description

TI's CC2541 is available in two different versions: CC2541F128 with 128kB flashand CC2541F256 with 256kB flash.


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

2, design plan

2.1. Introduction


The CC2541Bluetooth Smart Remote Kit provides a reference platform for the development oflow-power Bluetooth remote control applications. It is based on TI'sindustry-leading low-power Bluetooth devices and the development, testing,debugging and remote control applications required for the evaluation of theCC2541. The kit includes an advanced programmable remote control, 6-axis motionsensing (3-axis accelerometer and 3-axis gyroscope), USB dongle and a debugger.

Advanced remote USB adapters come pre-programmed to hide in their respectiveroles and GATT Profile HID Reporting Services, including keyboards, consumercontrol keys and mouse reports. The low-power Bluetooth software stack includedin the sample application.

Advanced remote control can be directly connected to a Bluetooth smart deviceready to support hiding in the GATT, such as Windows 8. The USB dongle can beused as a bridge, and the interface device does not have Bluetooth Smart Readysupport, such as Windows 7.

The CC2541's advanced remote control is designed as a hidden peripheral (BLEslave), operating according to specifications placed in the GATT profile. It ispre-installed in a plastic case with a rubber button, a battery case and a holeto access the programming head.

The CC2541's USB dongle can be used to simulate any Bluetooth low energybehavior, but is usually used as a central device (BLE Master) and HID host.This kit has a core role in pre-installed firmware, as a hidden service clientfor advanced remote control and sending and receiving input data emulation of ahuman interface device (USB HID) in a connected Windows, Linux or OSX computer.CCdebug Debugger's Flash software is available on USB dongle as well asadvanced remote control. It can also be used for debugging with IAR EmbeddedWorkbench software. The kit's RF board and IC are FCC certified and tested tomeet ETSI / R & TTE temperatures from 0 to 35 ° C.

2.2. Schematic design


2.2.1 powercircuit

Advanced remote control operation with three 1.5V alkaline batteries AAA (LR03)powered. A 3.3V LDO (tps78330) low voltage conversion circuit from 4.5V to3.3V.

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 buzzers, gyroscopes,accelerometers, and shift registers for key scans. As a SOC chip solution, theCC2541 can extract all GPIOs for schematic and PCB design for secondarydevelopment. Such as the E104-BT01 series of Chengdu Yiyi Electronic TechnologyCo., Ltd. to meet this requirement.