68HC11 Bootstrap mode

In 1999, I received a Super T-Comp; a 68HC11 based microcontroller board that is similar to the Handyboard.

While working with it I released the sacred smoke. I blew out 3 chips.

I repaired the damage, but I couldn't get it to work right again. So it sat in my toybox waiting for me to try again.

In 2010, I am taking a class in embedded systems; so it is time to try again.

Inspecting the board again, I found a bad chip that I missed; a NAND gate driving the external RAM. I will fix that this week.

Regardless I should be able to talk to T-Comp in Bootstrap mode. PCBug11 is the original tool for talking to 68HC11. It doesn't run on modern (fast) computers.

So I tried TeraTerm terminal software. Finally did established communication this morning.

68HC11 has 4 modes:

Single Chip: no external RAM

Expanded: external RAM

Bootstrap: single chip, using bootstrap loader in ROM

Test: Uh? don't know

Bootstrap Mode

Hold ModA and ModB low

Toggle Reset

Release ModA and ModB

within a second

send a byte over SCI (serial port) at 1200 Baud, No parity, 8 bits, 1 stop bit.

It is now ready to accept a 256 byte program. 68HC11 will echo bytes. Once it recieves 256 bytes, the program counter resets to $0000 and starts to run the loaded program. In theory.

Hacking the PSP

Everyone has hacked the PSP to put non-Sony firmware on.

You can still run your games, AND install homebrew stuff.

This was the original goal when I bought my PSP. I got distracted by actually playing games.

I finally got around to doing it.

I have the GOW edition PSP slim, it had Sony firmware V3.94 installed.

I sort of followed the instructions that I found here

http://forums.pspslimhacks.com/tutorials/5-guide-psp-custom-firmware-reference-guide-minor-update.html

Things you need:

Pandora Battery - modified battery to allow access to the PSP bootstrap mode,

I borrowed one

Sony memory stick - 1Gb stick works fine

PSP Grader v0.008 - installs firmware, I got it here

http://pspslimhacks.com/psp-grader-v008/

modified PSP firmware - overwrites the Sony firmware, I got it here

http://www.psp-hacks.com/file/1568

Connect the PSP to your PC; start USB mode.

Copy the Sony memory stick to PC

Format the Sony memory stick

Start PSP Grader

Locate the eboot.pbp in the PSP_500_FW.zip

Download file to stick

Disconnect and power off the PSP

Remove battery

Insert memory stick (if you haven't)

Hold down the L button

Insert the Pandora Battery (often PSP auto-starts) and start PSP

Back up NAND

Restart PSP

Install 5.00 M33 (or similar)

Done.

I have spent all my time playing a Magic the Gathering Homebrew (Wagic) in stead of programming anything.