WACOM Intuos 4 / Pro Pen Gen 1
Starting from Intuos 4, WACOM seems to have switched to a common protocol for all their high-end products (i.e. excluding licensed Feel-EMR products and the Bamboo line) The protocol and overall system design is nearly identical to the Intuos 3 series, but with some minor differences.
Data Link
Parameters
- Carrier Frequency: 669kHz (1.495us)
- TX Symbol Definitions:
- Pulses:
- Bit 0: S0: 43.6us (29 cycles)
- Bit 1: S1: 208.4us (139 cycles)
- Reset: R: 1.666ms (1111 cycles)
- Gaps:
- Short Gap: GS: 82.2us, 106.8us, 126us
- Long Gap: GL: 1044us, 2.969ms
- Meta Symbols:
-
Sample: SMP: S0, GS
-
RX Symbol Definitions:
- Tuned, returning signal: Logic 0
- Detuned, no returning signal: Logic 1
Tablet to Pen Communication
The last 3 pulses of the TX signal are used to change the pen's operating mode.
| TX Duration | Encoded Bit |
|---|---|
| 42.2us | 0 |
| 210.8us | 1 |
| 1.645ms | Interval between frames |
| 3.73ms | Accessory Reset? |
Known Modes:
| Bits | Next Mode |
|---|---|
| 3'b011 | ID Mode |
| 3'b100 | Serial Number Mode |
| 3'b000 | Running Mode |
Pen to Tablet Communication
The pen will output logic 0 when the tablet is requesting more bits than what the mode provides.
Mode 011: ID Mode
Sequence: S1, GS, S1, GS, R, 33*SMP, GL
| Bits | Meaning |
|---|---|
| 0 | Always logic 1 |
| 1-14 | Accessory ID |
| 15-28 | Locating, 7 taps, twice each |
Known IDs:
| Accessory ID | Accessory Type | Model Number |
|---|---|---|
| 10111111111010 | Grip Pen Tip | KP-501E |
| 10101111111010 | Grip Pen Eraser | KP-501E |
| 10111000111010 | Wacom Pen 2K | LP-190K |
| 10111001111010 | Wacom Pen 4K | LP-1100K |
| 10111101111010 | Wacom Pro Pen Slim | KP-301E |
| 10111101111010 | Wacom Ballpoint Pen | KP13300D |
Mode 100: Serial Number Mode
Sequence: S1, GS, S0, GS, S0, GS, R, 63*SMP, GL
Pen tip and eraser have the same serial mode response. Note: It seems that Wacom is also not sure which is logic 0 and which is logic 1. In some cases, the software may report serial number in logical reverse.
| Bits | Meaning |
|---|---|
| 0 | Always logic 1 |
| 1-8 | Unknown 1 |
| 9-40 | ~SN, LSB first |
| 41-50 | Unknown 2 |
| 51-64 | Locating, 7 taps, twice each |
Known Serial Numbers:
| Model | Expected S/N | UNK1 | S/N | UNK2 |
|---|---|---|---|---|
| KP-501E | 0xDC7ED690 | 11110111 | 00001001011010110111111000111011 | 1100110101 |
| LP-190K | TBD | 11111111 | 01001111100110110111111001111011 | 0101010011 |
| LP-1100K | 0x288D1E56 | 11111111 | 10010101100001110100111011101011 | 0110101101 |
| KP-301E | TBD | 11110111 | 10100100100010001111111000101110 | 0011100010 |
| KP13300D | TBD | 11011111 | 01110010101001111111111011001001 | 0010001001 |
Mode 000: Running Mode
Sequence: R, 23*SMP, GL
The pen uses a very interesting base-3 encoding with 3-PSK modulation (Actually it's 2-PSK + OOK). The tablet demodulates the waveform with I/Q down conversion. The detailed decoding process is documented in a separate Python notebook: Intuos 4 Data Decoding.
After decoding, the ternary data is expanded to a string of binary data. The exact encoding of the binary is differ from accessory to accessory. For example, KP-501E has 11-bit pressure data plus 2-bit button data, and LP-1100K has 12-bit pressure data plus 2-bit button data.
Known Models
Tablets:
- WACOM Intuos 4 Series (PTK-440, PTK-640, PTK-840)
- WACOM Intuos S/M (CTL-4100, CTL-6100)
- WACOM Intuos S/M BT (CTL-4100WL, CTL-6100WL)
Pens:
- WACOM Grip Pen (KP-501E, KP-501E2)
- WACOM Pro Pen (KP-503E)
- WACOM Pro Pen Slim (KP-301E)
- WACOM Ballpoint Pen, Finetip Pen (KP13300D, KP13200D)
- WACOM 4K Pen for Intuos (LP-1100K)
References
- None