AN2295 Freescale Semiconductor / Motorola, AN2295 Datasheet - Page 8

• Manufacturer Part Number: AN2295
• Description: Developers Serial Bootloader for M68HC08 and HCS08 MCUs
• Manufacturer: Freescale Semiconductor / Motorola

FC Protocol Description
Interpreting MCU Commands
After communication between the MCU and the PC is established, the MCU enters the main command
interpreter loop.The MCU executes simple commands to reprogram its own nonvolatile memory. The
communication is conducted on a master-slave mechanism, where the PC issues the commands, the
MCU executes them and acknowledges the completion of each command, either by data or by a single
ACK character.
The minimal set of commands is comprised of:
Two more basic commands are implemented for pure reprogramming:
If the user needs a verification feature, one additional (read) command must be compiled into the MCU
code. For pure reprogramming purposes (minimal configuration), it is not required.
Figure 6
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Ident Command
Quit Command
Erase Command
Write Command
Read Command
illustrates a typical command and response.
ACK IS SENT AT CORRECT DATA RATE
NO CALIBRATION REQUIRED
MCU
Developer’s Serial Bootloader for M68HC08 and HCS08 MCUs, Rev. 6
Figure 5. Start-Up Communication Without Calibration
ACK IS SENT AT SPECIFIED DATA RATE
CORRECT $FC CHARACTER IS RECEIVED WITHIN TIME-OUT
PC
Freescale Semiconductor