AN2262
Description
This document details the hardware and software required for a low-cost wireless communication application based on: * The Motorola 8-bit microcontroller (MCU), MC68HC908GP32 Accompanied by the Motorola RF (radio frequency) chip set: - MC33493 (transmitter)(1) - MC33591/3 (receiver) The main purpose of this document is to demonstrate the ability of the 8-bit MCU to be connected by means of a wireless medium. Or, in other words, how you can connect several HC08s forming a simple wireless network.
Key Features
- Selectable 315/434/868/915 MHz operation Single-channel, OOK (on-off keying), or FSK (frequency shift keying) operation Fully-integrated voltage controller oscillator (VCO) Data rate: 1 to 11 kBaud A transmitter: MC33493(1) - 14-pin thin shrink small outline package (TSSOP) - Low current consumption: 15 mA typical in transmit mode A receiver: MC33591/3 - 24-pin low-profile quad flat pack (LQFP) - Low current consumption: 5 mA typical in run mode - An image-cancelling mixer - Manchester coded data clock recovery - Fully-configurable using the serial peripheral interface (SPI)
- Circuit Description A schematic of the RF-08 demo board is provided in Figure
- The MC68HC908GP32 MCU itself needs only a few external elements for its operation. A wide range of peripheral functions including a 32-Kbyte FLASH memory are integrated on-chip. For the RF-08, the 44-pin quad flat pack (QFP) version was chosen instead of the 40-pin dual in-line package (DIP).
- The MC33491 (code name Tango II) is no longer available. The MC33493 (code name Tango III) is it’s full replacement. The MC33493 input pins are not specified above VCC voltage. Thus, the MC33493 cannot be used within described RF-08 schematics that employ R1 and R3 serial resistors to protect the MC33493 3-V interface. For interfacing between an 5 V MCU and 3 V MC33493 a proper level shifter must be designed or a different configuration used. For a more detailed description, refer to the MC33491 to MC33493 Migration Notes on page 36. 4 Wireless HC08 Modem MOTOROLA 44 43 42 16 17 31 30 1 2 3
