Linux CLI Monitor Loader for Motorola/Freescale/NXP MC68HC908GZ60

Monitor loader is a PC side software which can update program memory of an empty (virgin) microcontroller. Disadvantages are it needs special hardware interface and it is slow. My one is available here in Python language, or here in C language. I propose the Python one.

Bootloader is software embedded in the microcontroller, which can receive data from a hardware interface and write it into its own program memory. This software needs to be programmed into the microcontroller only once by a monitor loader. My one is available here.

Downloader is PC side software. The communication partner of Bootloader. It can send the pre-compiled software (or any other data) to data to microcontroller through the supported hardware interface. My one is available here in Python language, or here in C language. I propose the Python one.

Application is the real software for the main purpose. It is easier if you start your application software from an application template. Application template is a sample software which initializes and uses almost all modules of microcontroller for some basic purpose. You can download into uC and it already works and does something. You just need to modify it for your purpose. My one is available here.

My motivation was, I still have working hardwares, but I couldn't update the sw because loaders developed for WinXP and built in COM port do not work on Win7, Win10 and USB-RS232 devices. Moreover, I switched from Windows to Linux several years ago. Therefore I could not use prog08sz any longer, as I used 10 years before.

It supports only basic monitor features what are needed to erase flash and download software into flash. Usually I just use monitor loader to download the bootloader into an empty uC. From this point on, system software can be downloaded easily through RS232 UART or CAN any times. Therefore I just implemented those functions, which are needed to download my bootloader.

• Mass erase entire flash memory
• Write S19 file content into flash memory
• Dump data from memory
• Define security bytes for connect device

• Erase range
• Debugging
• Change baud rate
• Write bytes or ranges
• ... (many other features prog08sz supported)

To be HW interface easy and cheap, buy TTL USB-Serial interface from China. I use FT232RL FTDI USB to TTL Serial Adapter Module for communication. This is supported by both Linux and Windows 10. The mini step up power supply board is used to generate Vtst for IRQ pin. With this, you just need some cable and that's it.

My first CPU card circuit diagram (schematic) is visible here.

More info is here.

The keyword is Linux. The software was developed on my Ubuntu Linux 16.04 LTS.

• Open terminal
• First check out files into a folder.
• Compile gzml by gcc gzml.c -o gzml
• Enjoy it.

./gzml

Print out usual help about version, command line options, tipical usage.

./gzml -e

Erase the entire Flash memory. If the security failed during connection phrase, the command will only mass erase Flash 1 (0x8000-0xFFFF) including security bytes. In this case, to erase Flash 2 (0x0462 - 0x7FFF) too, you need to execute the same command again. Since security bytes were erased, security will pass with default full 0xFF bytes, and Flash 2 will also erased.

./gzml hmdl.s19

Download software into Flash memory. This command does not erase Flash even if it would be needed. If you download into not erased memory, you will have verify errors.

./gzml -d 0xFF00

Dump memory content from address 0xFF00 - 0xFFFF. Default length of dump is 256. You can increase/decrease it by -l command line parameter. See help for more details.

If you only improve PC side features, just

• Edit gzml.c
• Compile gzml by gcc gzml.c -o gzml
• Enjoy it.

If you want to improve uC side code too (as I did), use bash update_loader.

You need php installed. Without php you need to convert loader routines from S19 to initialized C array manually. It is not a nice job, but possible. You can also write script for this in your favorite programming language. The task what my php script does is written easy to understand way in the script and the generated file (loader.c).

Let see update_loader bash script. It:

• compiles the flash erase and program routines (loader.asm) using asm8 compiler
• php script creates C source defines for start address of routines from LST file
• php script creates C source array definition from S19 file
• deletes gzml previous instance if there is
• compiles gzml by gcc

Development procedure:

• Modify any source (gzml.c , loader.asm)
• Call bash update_loader
• Try it

Unfortunately I couldn't get work non-standard baud rate (14400) on Linux. Therefore I decided to change quarz from 8MHz to 5.33MHz to have standard (9600) monitor baudrate. I haven't found 5.33MHz quarz only if I buy 1000 pieces. :) I could only buy 5.2MHz from Conrad, which is still inside the tolerance range. So, baud rate is 9600 when PTB4=0 or 4800 when PTB4=1. Defauls baudrate is 9600. If you do not know state of PTB4, first use default 9600. If you got error message "Target echo failed, sent 0xFF, got 0xFE", try it with 4800. Do not forget, quarz change need to update PLL setup in system software too.

I just tested those features what I used during download bootloader. Not all available features were tested. If you find bug, or do not like how it works, feel free to fix or modify.

• Mass erase when security passed
• Mass erase when security failed
• Program into area 0x8000 - 0xFFFF
• Program into area 0x0980 - 0x1000
• Dump from memory
• Motherboard mounted ttyS0
• USB Serial interface ttyUSB0 (both FT231XS and ATEN UC232A1 )

This is free. You can do anything you want with it. While I am using Linux, I got so many support from free projects, I am happy if I can help for the community.

Many thanks for my predecessors! They saved my hardwares for further use and by this way helped to save green environment. I mean I do not need to produce/buy new device.

• Based on bl08.c (https://github.com/jaromir-sukuba/bl08):
• Copyright (c) 2004,2008 Kustaa Nyholm
• Copyright (c) 2008 Robert Larice (SWI return to MON, QY2 chip)
• Copyright (c) 2010 Tormod Volden
• Copyright (c) 2013 Jaromir Sukuba (added A and B ROM routines entry instances,

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