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SRAM Issues

The X68000 has 16KB of battery-backed SRAM, which is used to store basic system settings. It can also store drivers or small programs. Since it's battery-backed, and since the batteries that shipped in most X68000s are a decade or two past their useable life, this will cause some problems. Symptoms of a dead or dying battery include loss of settings, the Generic Error, and loss of whatever program was stored in the SRAM. Sometimes the battery can leak, causing damage to the PCB so it is highly advisable to replace it or change it for something more safer. It is a GB50H-3 50mAh 3.6V battery which can be replaced with a CR-2032 along with a battery holder.

Sometimes the SRAM can get corrupted. This can either be caused by a virus, a dying (but not completely dead) battery, or a sloppily-written program crashing and vomiting all over the SRAM space. If the SRAM is corrupted, you will get this message at boot time instead of a normal “insert disk” screen:

Roughly translated, it reads “Error. Please reset the computer.” You can bypass it by leaving a bootable disk in the drive while resetting. You may or may not need to hold down OPT.1 to boot from floppy.

How do you get rid of it? First, you need to replace your SRAM battery if it's old. Then, if you have an XVI or later, just hold down CLR while powering on the machine and it should give you a prompt that will ask you if you want to erase the SRAM and return all settings to their defaults:

If you have an older machine the process is more involved. You have two options:

The most simplest is to download SRAMLOAD.Lzh and use SRAM_CLR.R to clear the contents of SRAM.

You can also use a debugger. This site reccommends you use the one from C Compiler PRO-68K. Boot the first disk (an image is in the archive called “XC2101I.LZH”). After answering “N” to the prompt that pops up it should dump you back in HumanOS. Then type:

mes e8e00d 31
mes ed0000 00
mes e8e00d 00

This should reset the SRAM. Pop the disk out, restart and you should get your normal disk prompt back. Make sure to redo your settings in SWITCH.X, as they'll be reset to their default options after this.

x68000/sram_issues.txt · Last modified: 2019/08/27 20:45 by