User's Manual Part 2

Wireless Sensing Triple Axis Reference design, Rev. 0.9
Freescale Semiconductor 35
Chapter 5 Software Design
5.1 Introduction
This section describes the design of the ZSTAR software blocks. The software description comprises
these topics:
•
SMAC (Simple Media Access Controller) modifications description
• ‘Air’
ZSTAR RF protocol protocol description
• Serial
STAR protocol and ZSTAR extensions (over USB) protocol description
• AN2295
Bootloader (over USB) implementation notes
5.2 SMAC (Simple Media Access Controller)
The SMAC is a simple ANSI C based code stack available as sample source code which can be used to
develop proprietary RF transceiver applications using the MC13191.
5.2.1 SMAC Features
• Compact footprint:
– 2K FLASH
– 10 bytes (+ maximum packet length) RAM
– As low as 16kHz bus clock
• Can be used to demonstrate coin cell operation for a remote control
• MC13191 compatible
• Very-low power, proprietary, bi-directional RF communication link
• ANSI C source code targeted at the HCS08 core and portable to almost any CPU core (including
4-bit)
• Low priority IRQ
• Sample application included, extremely easy to use
• Liberally commented
• Metrowerks CodeWarrior Experimental edition for support
5.2.2 Modifications of SMAC for ZSTAR demo
The development of the ZSTAR software is based on the free SMAC stack available from Freescale. The
SMAC version used was 4.1a. Two sorts of modifications were made since the original version did not
support the HC08 family or the MC9S08QG8 derivative of the 9S08 family. All changes are made using
conditional compile options, using ZSTARQG8 and ZSTARJW32 definitions.
A fully detailed description of the SMAC is in the SMAC Reference Manual (SMACRM.pdf), available
together with SMAC source code.