Microchip 公司的PIC12LF1840T48A是具有超低功耗的(XLP)的集成了小于1GHz 安全系統" mhz="" title="安全系統">安全系統的遙控無鑰匙進入以及家庭和建筑物自動化系統.本文介紹了PIC12LF1840T48A主要特性, 應用框圖以及采用CTRL線和PRESET模式的433.92 MHz發送器參考設計電路圖.

The PIC12LF1840T48A’s combination of features in a single, 14-pin TSSOP package makes it ideal for space-, power- and cost-constrained applications, such as remote keyless entry fobs for automobiles, garage doors and home security systems, as well as a broad range of other home and building automation systems.

In addition to being optimized for secure wireless communication, the PIC12LF1840T48A is designed to maximize battery life via an extremely low operating voltage of 1.8V. Furthermore, the XLP microcontroller has extremely low sleep current consumption, and is efficiently integrated with the transmitter to enable fast wake-up and send functionality that takes full advantage of the MCU’s 8 MIPS operation.

PIC12LF1840T48A主要特性:

High-Performance RISC CPU:

• Only 49 Instructions to Learn:

- All single-cycle instructions except branches

• Operating Speed:

- DC – 32 MHz oscillator/clock input

- DC – 125 ns instruction cycle

• Interrupt Capability with Automatic Context Saving

• 16-Level Deep Hardware Stack with Optional Overflow/Underflow Reset

• Direct, Indirect and Relative Addressing modes:

- Two full 16-bit File Select Registers (FSRs)

- FSRs can read program and data memory

Flexible Oscillator Structure:

• Precision 32 MHz Internal Oscillator Block:

- Factory calibrated to ± 1%, typical

- Software selectable frequencies range of 31 kHz to 32 MHz

• 31 kHz Low-Power Internal Oscillator

• Four Crystal modes up to 32 MHz

• Three External Clock modes up to 32 MHz

• 4X Phase Lock Loop (PLL)

• Fail-Safe Clock Monitor:

- Allows for safe shutdown if peripheral clock stops

• Two-Speed Oscillator Start-up

• Reference Clock module:

- Programmable clock output frequency and duty-cycle

Special Microcontroller Features:

• 1.8V-3.6V Operation

• Self-Reprogrammable under Software Control

• Power-on Reset (POR), Power-up Timer (PWRT) and Oscillator Start-up Timer (OST)

• Programmable Brown-out Reset (BOR)

• Extended Watchdog Timer (WDT)

• In-Circuit Serial Programming™ (ICSP™) via Two Pins

• In-Circuit Debug (ICD) via Two Pins

• Enhanced Low-Voltage Programming (LVP)

• Programmable Code Protection

• Power-Saving Sleep mode

Low-Power Features:

• Standby Current:

- 520 nA

• Operating Current (not transmitting):

- 34.5 μA @ 1 MHz, 1.8V, typical

• Transmitting Current:

- 9mA @ 0 dBm

- 16.5 mA @ 10 dBm

RF Transmitter:

• Fully Integrated Transmitter

• FSK Operation up to 100 kbps

• OOK Operation up to 10 kbps

• Operation in 418, 434 and 868 MHz Bands

- 8 Selectable center frequencies

• +10 dBm or 0 dBm Configurable Output Power

Analog Features:

• Analog-to-Digital Converter (ADC) module:

- 10-bit resolution, 4 channels

- Conversion available during Sleep

• Analog Comparator module:

- One rail-to-rail analog comparator

- Power mode control

- Software controllable hysteresis

• Voltage Reference module:

- Fixed Voltage Reference (FVR) with 1.024V and 2.048V output levels

- 5-bit rail-to-rail resistive DAC with positive and negative reference selection

Peripheral Features:

• 5 I/O Pins and 1 Input Only Pin:

- High current sink/source 25 mA/25 mA

- Programmable weak pull-ups

- Programmable interrupt-on-change pins

• Timer0: 8-Bit Timer/Counter with 8-Bit Prescaler

• Enhanced Timer1:

- 16-bit timer/counter with prescaler

- External Gate Input mode

- Dedicated, low-power 32 kHz oscillator driver

• Timer2: 8-Bit Timer/Counter with 8-Bit Period Register, Prescaler and Postscaler

• Enhanced CCP (ECCP) module:

- Software selectable time bases

- Auto-shutdown and auto-restart

- PWM steering

• Master Synchronous Serial Port (MSSP) with SPI and I2CTM with:

- 7-bit address masking

- SMBus/PMBusTM compatibility

• Enhanced Universal Synchronous Asynchronous Receiver Transmitter (EUSART) module:

- RS-232, RS-485 and LIN compatible

- Auto-Baud Detect

• Capacitive Sensing (CPS) module (mTouchTM):

- 4 input channels

• Data Signal Modulator module:

- Selectable modulator and carrier sources

• SR Latch:

- Multiple Set/Reset input options

- Emulates 555 Timer applications

圖1.PIC12LF1840T48A 方框圖

圖2.PIC12LF1840T48A應用框圖

A reference schematic diagram with an RF filter and matching network is provided. The component values are given for 433.92 MHz. The crystal is a low-cost 26 MHz HC-49.

圖3.采用CTRL線的發送器參考設計電路圖

圖4.采用PRESET模式的發送器參考設計電路圖

詳情請見:
http://ww1.microchip.com/downloads/en/DeviceDoc/41594A.pdf
和
http://ww1.microchip.com/downloads/en/AppNotes/01393B.pdf