This is not a project, but a challenge !
Did you ever have a look at the PIC16 family instruction set ?
Microchip datasheets announce 35 instructions, for sure they are here, but can't we get a little bit much from these PICs ?
It's time to become closer to PIC16 reduced instruction set, to see if we can extend it.
First, get familiar with instruction format : PIC16 family has a 14 bits wide instruction set, with MSBs as opcode and LSBs as sub-opcode or operand.
Here is the link to the "Microchip PICmicro Mid-Range MCU Family Reference Manual" (datasheet DS33023A) :
http://ww1.microchip.com/downloads/en/devicedoc/33023a.pdf
this figure is coming from this manual :
Microchip Datasheet DS33023A P.526
Here is the instruction set list sorted by type, you can count once more : 35 official mnemonics.
Microchip Datasheet DS33023A P.525
Now, we can try to re-arrange the table, and sort it by opcode number.
I wrote the documented opcodes in green, and the undocumented opcodes in red :
We can see immediately that there are holes in the instruction set sequence.
Correct me if I'm wrong, but there may be a total of 119 secret opcodes.
Here is the table of the undocumented opcodes :
|
Mnemonic, |
Description | Cycles | 14-bit Instruction Word |
Status |
Found out by ..., on .... |
| ??? | ??? | ??? | 00 0000 0000 0001 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0000 0010 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0000 0011 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0000 0100 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0000 0101 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0000 0110 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0000 0111 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0000 1010 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0000 1011 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0000 1100 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0000 1101 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0000 1110 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0000 1111 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0001 0000 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0001 0001 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0001 0010 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0001 0011 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0001 0100 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0001 0101 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0001 0110 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0001 0111 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0001 1000 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0001 1001 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0001 1010 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0001 1011 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0001 1100 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0001 1101 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0001 1110 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0001 1111 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0010 0001 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0010 0010 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0010 0011 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0010 0100 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0010 0101 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0010 0110 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0010 0111 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0010 1000 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0010 1001 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0010 1010 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0010 1011 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0010 1100 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0010 1101 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0010 1110 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0010 1111 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0011 0000 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0011 0001 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0011 0010 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0011 0011 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0011 0100 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0011 0101 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0011 0110 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0011 0111 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0011 1000 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0011 1001 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0011 1010 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0011 1011 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0011 1100 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0011 1101 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0011 1110 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0011 1111 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0100 0001 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0100 0010 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0100 0011 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0100 0100 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0100 0101 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0100 0110 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0100 0111 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0100 1000 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0100 1001 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0100 1010 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0100 1011 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0100 1100 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0100 1101 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0100 1110 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0100 1111 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0101 0000 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0101 0001 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0101 0010 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0101 0011 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0101 0100 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0101 0101 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0101 0110 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0101 0111 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0101 1000 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0101 1001 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0101 1010 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0101 1011 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0101 1100 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0101 1101 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0101 1110 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0101 1111 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0110 0001 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0110 0010 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0110 0101 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0110 0110 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0110 0111 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0110 1000 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0110 1001 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0110 1010 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0110 1011 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0110 1100 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0110 1101 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0110 1110 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0110 1111 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0111 0000 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0111 0001 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0111 0010 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0111 0011 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0111 0100 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0111 0101 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0111 0110 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0111 0111 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0111 1000 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0111 1001 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0111 1010 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0111 1011 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0111 1100 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0111 1101 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0111 1110 | ??? | your name here ??? |
| ??? | ??? | ??? | 00 0000 0111 1111 | ??? | your name here ??? |
| ??? | ??? | ??? | 11 1011 kkkk kkkk | ??? | your name here ??? |
Maybe all of these opcodes are NOPs, or will freeze the MCU but maybe not, and at least we shall know !
Who will try to find out some of them ?
If you have some ideas, please report them to my forum.
If you help me to fill this table, your name will be added to the hall of fame.
Thanks a lot, and enjoy the treasure hunt !
Bruno