This section provides some interesting hardware documentation on the HP28 and its peripheral devices. For more information, please contact the author(s) of the articles.
The assembly listings in the articles below may cause total loss of all data on your HP28. The information in the articles is provided ``as is'' without warranty of any kind, either expressed or implied. The entire risk as to the reliability and the quality of the information is with you.
In other words: Always make absolutely sure you have a full backup of your stuff before attempting any of the programs below!