The integrated 24 bit microprocessor was developed by acam  and has a reprogrammable 1k x 8-Bit EEPROM memory. A comprehensive instruction set allows comfortable and efficient programming in Assembler to adopt the PSØ8 to various tasks.

 

Several of the 70 opcodes are very similar to known instructions like those for the 8051, e.g.:

 

move x, 20	-> x is set to 20
add x, y	-> Content of y is added to x
clear x	-> Clears the content of x

 

In addition there are commands specially adopted to the 24 bit architecture of the microcontroller. They are very effective and code saving. Examples are:

 

mult24 x, y	-> 24-Bit multiplication of register x and y
no2lcd	-> Conversion of a number for direct display on the LCD
gotoBitS x, 18, target	-> Conditional jump     (if Bit 18 of x is set go to target)

 

The available memory space of 1K is more than sufficient for most applications because opcodes like 24 bit multiplication need only 2 bytes or the display of a number on the LCD needs only 3 bytes. The figure on the right gives an overview of the available opcodes.

 

Further features of the assemler are:

• Comments in single and multiple lines
• Include file handling
• Conditional and un-conditional jumps
• Constants declaration
• Number formatting in decimal and hexadecimal manner
• Subroutines

 

The PSØ8 instruction set is has 75 commands and each unique opcode is transscribed by the CPU. ROM coded commands like 24 bit and 48 bit multiplication or division simplify programming.