Project HP F4480 Pen Controller

HP F4480 Pen Controller

This page documents my investigations into the wire protocols of the HP F4480 Pen Controller.

The nominal voltages recorded on the flex cable are in the following table, along with the disconnect results from my breakout cable:

Pin	Voltages	Dir	Name	Disconnect	Comment
1	0.0v	Out	ENC_A	No head movement	Encoder A Output
2	0.0v	Out	ENC_B	No head movement	Encoder B Output
3	0.0v	Gnd	GND	No change	Ground
4	1.6v	In	#CYM_D0	CYM ink fires constantly	CYM Ink Control
5	0.0v / 0.9v / 1.1v	In	#CYM_D1	CYM ink firess constantly	CYM Ink Control
6	0.0v	Gnd	GND	No effect	Ground
7	0.0v / 1.5v	?		No effect
8	0.0v / 1.5v	?		Immediate stop of printing
9	0.0v	Gnd	GND	None	Ground
10	1.6v	In	#BK_D0	Black ink fires constantly	Black Ink Control (Looks like data, I guess)
11	1.1v / 0.9v / 0.0v	In	#BK_D1	Black ink fires constantly	Black Ink Control (110us off, 1.6us on)
12	0.0v	Ground	GND	None	Ground
13	LVCMOS3.3	Out	INK	No ink fires	Ink fire timing control (1.5us pulse)
14	LVCMOS3.3	In/Out	IO_DATA	immediate stop of print, E - Ink	ASIC Data
15	3.3v	Vcc	VCC	immediate stop of print, E - Ink	3.3v for logic
16	LVCMOS3.3	Out	IO_CLK	immediate stop of print, no error	ASIC Clock
17	16v	In	VINK		Voltage for ink jet
18	16v	In	VINK		Voltage for ink jets
19	16v	In	VINK		Voltage for ink jets
20	16v	In	VINK		Voltage for ink jets

NOTE: IO_DATA appears to update for sampling on both positive and negative edges of IO_CLK, IO_CLK is 4Mhz, and nominally low when idle.

I have a tarball of some waveform dumps, in CSV and VCD (GtkWave) formats: HP-F4480-Pen-Controller.zip