Micro­power

1. The program would not normally reside in memory (unless, as in the author’s case, on an EPROM board that can be paged in or out of the system, see INMC80 No. 4). Normally, it would be loaded from disc or tape.

The listing was written using the CP/M Editor ‘ED’ for assembly by Macro 80, because program development is easier with these more powerful utilities. It should be easy to alter it to suit ZEAP. The main changes required are:–

Leave out the colons after labels;
Remove the assembler directives END,​.Z80,​ASEG,​.PHASE and .DEPHASE;
Substitute a suitable memory ORG address;
Substitute " in place of ' in compare instructions.

If you have ‘ED’ or any other editor with MACRO find/​substitute commands it should be very easy to make the changes needed to the Source code. Otherwise, there should be few problems. The PIO ports are defined for the I/O board (using ports 14 and 15). These can be changed in the equates section of the listing.

Soft­ware Operation

The program is written so that the user is reminded, by means of messages on the screen, to take suitable precautions when handling chips. User input is in the form of single key replies to prompts on the screen. All entries are echoed on the screen and the user may change them. The various routines are listed in the form of a ‘menu’.

When the program is executed, the title is placed on the left side of the top (unscrolled) line of the screen, and warnings about chip handling appear for a couple of seconds. The program then prompts the operator to press key ‘C’ when he is ready to continue. Whilst waiting for a response, the program display a message warning the operator to switch off when inserting or removing chips. When key C is pressed a prompt asks for the type of EPROM to be handled – key A should be pressed for 2708s, key B for 2516/2716s.

When this entry has been made, the user is asked to verify it by a ‘Y’ or ‘N’ response. If ‘N’ is entered the program repeats the request for the EPROM type, while on receipt of ‘Y’ the type selected is displayed on the right hand side of the top line, and remains there until changed. In addition the value stored in the program workspace at the location ROMFLG is set to 04H for 1K EPROMs, or 08H for 2K EPROMs.

The ‘Menu’ for the five routines is then displayed, together with a list of the keys needed to access the routines. Once a routine has been selected and verified, it is