SX1230是窄帶/寬帶315 MHz, 434 MHz 868 MHz和915 MHz ISM頻段發送器，可編程輸出功率從+17 dBm 到 -18 dBm，比特速率高達600kbps，FSK, GFSK, MSK, GMSK 和OOK調制，單獨使用時不需要主MCU，在1.8V-3.7V時有恒定的RF性能，低相位噪音（50kHz時為-95 dBc/Hz），主要用在無鑰匙進入（RKE）系統，遙控和安全系統，語音和數據通信鏈接，生產過程和建筑物/家庭控制，有源RFID，AMR/AMI平臺。
圖1SX1230單獨應用電路圖
圖2SX1230和MCU接口電路圖
圖3SX1230 RKE演示板接收器電路圖
圖4434MHz頻段17dBm輸出功率匹配電路圖
圖5315MHz頻段17dBm輸出功率匹配電路圖
圖6915MHz頻段13dBm輸出功率匹配電路圖
圖7868MHz頻段13dBm輸出功率匹配電路圖
圖8315/434MHz頻段13dBm輸出功率匹配電路圖
圖9SX1230參考設計電路
無鑰匙進入系統（RKS）交鑰匙參考設計
Turnkey Reference Design for Remote Keyless Entry System
A remote keyless system (RKS) is a system designed to remotely permit or deny access to premises or automobiles.
In the case of automobiles an RKS performs the functions of a standard car key without physical contact; power door systems can be locked or unlocked from several feet away or even from inside a building.
A remote keyless system can include both a remote keyless entry system (RKE) and a remote keyless ignition system (RKI).
Remote keyless systems first began appearing as an option on several American Motors vehicles in 1983. Most RKE systems operate at 315MHz in North America and Japan, and 433.92 MHz in Europe. Modern systems implement encryption to prevent car thieves from intercepting and spoofing the signal.
The functions of a remote keyless entry system are contained on a key fob or built into the ignition key handle itself. Buttons are dedicated to locking or unlocking the doors and opening the trunk (or, on sport utility vehicles and station wagons, unlock/open the rear tailgate). Some cars will also close any open windows and roof when remotely locking the car. Some remote keyless fobs also feature a red panic button which activates the car alarm as a standard feature.
Some car engines with remote keyless ignition systems can be started by the push of a button on the key fob. For offices or residences, the system can also be coupled with the security system, garage door opener or remotely activated lighting devices.
The SX1230-13RKEA433 reference design kit provides a turnkey platform. for highly secure, low-power, multi-band wireless remote keyless entry (RKE) systems. This RKE kit integrates Semtech’s high-performance transmitter, tranceiver and switching regulator ICs with Microchip’s KEELOQ? code-hopping technology running on PIC? microcontrollers (MCUs). The kit helps simplify and accelerate the development of secure, high-performance and cost-effective RKE systems for vehicles, office buildings and homes, and provides a single platform. that works across virtually all major frequency regulations.
The RKE reference-design hardware includes transmitter (Tx) and receiver (Rx) boards, multi-band PCB antenna and Microchip MCUs, and runs Microchip’s KEELOQ code-hopping encryption software. Confidential information is stored inside the Flash memory of the PIC microcontroller, while the KEELOQ security algorithm encrypts the information in the RF transmission packets prior to any RF transmission, unlike some existing RKE systems in the market.
The Tx board pairs Semtech’s SX1230 industrial, scientific and medical (ISM) band transmitter with Microchip’s PIC16F631 or PIC16F677 8-bit MCUs. The Rx board employs Semtech’s SX1211 or SX1212 ISM transceivers with Microchip’s PIC16F631 or PIC16F677 MCUs. The RKE reference design also uses Semtech’s SC120 switching regulator -- the world’s smallest low VIN boost converter in a 1.5x2x0.6mm package.
參考設計主要特性:
Turnkey hardware and software RKE reference design, including:
- Hardware: integrated RF ICs, multi-band PCB antenna, MCU
- Software: KEELOQ code-hopping technology software
Highly secure:
- Encrypts all RF packets before sending, no plain text sent over air
- Code-hopping encryption produces unique RF transmission each time.
Saves design cost and time
- Same design supports multi-band (315, 434, 868, 915MHz) and multiple modulation formats (FSK, OOK, ASK)
No tuning for lower production costs
Long range: programmable POUT up to +17dBm
圖10參考設計Rx和Tx板外形圖
圖11無鑰匙進入系統（RKS）框圖
圖12無鑰匙進入系統（RKS）Tx方框圖
圖13。無鑰匙進入系統（RKS）Rx方框圖
圖14無鑰匙進入系統（RKS）加密系統方框圖
圖15無鑰匙進入系統（RKS）解密系統方框圖
圖16。無鑰匙進入系統（RKS）Tx板電路圖
圖17無鑰匙進入系統（RKS）Rx板電路圖
Tx 板材料清單（BOM）：
Rx 板材料清單（BOM）：
