What makes instructions?

Code lines are inserted in Edit mode.

When a program is Running，the execution starts from Line 000, followed by 001, 002, ...

tip

Line jump instructions, either conditional or unconditional, are often used when concepts like IF statements and loops are needed.

The interface of Edit mode looks like：

In Edit mode，all elements in a code line are input in hexadecimal.

info

The concept of instruction and opcodes on the JoyKit were inspirated from Solaris x86 Assembly Language.

Line Numbers

There are in total 512 lines available in the system, numbering from 000 to 1FF in hexadecimal.

Attempting to edit or to show lines with corresponding numbers greater than 512 i.e. 0x200 will lead to a warning message on the display:

Primary Display

MAX Line Exceeded

Instrcutions

An instruction is a number with 1-byte long (i.e. 0-255, or 0x00-0xFF in hexadecimal), it belongs to one of the following categories:

• Execution
• Register Operation
• Plotting & Printing
• Communication
• Peripheral Operations
• Logic and Computation

Please refer to each link above for details.

Opcode and Sub-Opcode

Two 16-bit opcodes (OP) are defined as optional parameters for the instructions, and each of both can be further divided and treated as two 8-bit sub-opcodes (sOP).

OP-0	OP-1
sOP00	sOP10
sOP01	sOP11

The compositon of OPs and sOPs depends on the current instruction. Besides, OPs may represent different meanings in different instructions.

Some specific instructions do not need opcodes, for instance, end of program instruction 0F, show background instruction 54, the values of OPs will be ignored in these instructions.

caution

Sometimes the bits in an OP is interpreted bitwise, or values may not be considered as numbers.

INST_Delay

When using delay instruction 02, OP-0 and OP-1 represent value and unit repectively.

INST_PROG_DELAY	No.	OP-0	sOP10	sOP11
Delay 1000 ms	02	03E8	00	00

02 03E8 0000

in which hexadecimal value 03E8 of OP-0 equals to 1000 in decimal，while OP-1 0000 determines unit of milliseconds.

INST_SET_LED_COLOUR

Another example is instrcution E4 for setting colours of the WS2812B full-colour LED.

E4 02FF 8000

Meaning that LED with index 02 is set to orange represented by FF8000.

R	G	B
FF	80	00

In this line, the sOP values are interpreted as below:

sOP00	sOP01	sOP10	sOP11
02	FF	80	00

Use Combo key →+↺️ to toggle top row of LCD1602 between showing decimals of single-byte (sOP) or double-byte (OP) SDR_switching。

tip

In the combo key description (such as →+↺️) in this document, the first key (→) is pressed and held, and then the second key (↺) is pressed.