Pinout

Roger Cheng

FormLabs Form 1+ OLED Pinout

I have a broken FormLabs Form 1+ laser resin 3D printer and I’m learning what I can from taking it apart. On its front panel is a small OLED dot-matrix display that I have been exploring. I have now successfully controlled that OLED module using an ESP8266 development board.

Confirming the speculation in this FormLabs forum thread, the OLED module is very similar to the Newhaven Display International NHD-2.23-12832UCB3. Both of their display areas are 2.23″ diagonal with 128×32 pixels of resolution. They both use a SSD1305 controller, but while Newhaven’s module provided a single row of 20 pins, FormLabs custom built their own circuit board connecting to the rest of the printer with a 10-wire IDC ribbon cable. Only 7 wires are actually used.

This OLED module is also very similar to Adafruit product #2675 Monochrome 2.3″ 128×32 OLED Graphic Display Module Kit but without Adafruit luxuries like 5V logic level shifter and power buffering capacitor.

This module only requires a power supply of 3.3V DC, because it has an onboard voltage boost converter to supply other voltages needed by OLED. All logic high signals are also 3.3V DC. Data communication is via SPI protocol with an additional command/data select input wire. When that wire low, the chip will interpret SPI traffic as commands and when high, SPI traffic will be sent to graphics frame buffer.

  1. Ground
  2. Vcc to supply 3.3V DC
  3. Command/Data select
  4. SPI Clock
  5. Reset (Active Low)
  6. SPI Data In (*)
  7. SPI Chip Select (Active Low)
  8. Unused
  9. Unused, but connected to mainboard I2C bus data line
  10. Unused, but connected to mainboard I2C bus clock line

(*) There is no SPI Data Out pin.

Now this pinout is documented, I will explore side curiosities like potential OLED burn-in.

Roger Cheng

Pinout for Asiahorse 120mm Fan (Magic-i 120 V2)

The Asiahorse Magic-i 120 V2 bundle included three 120mm cooling fans with integrated addressable RGB LEDs. These fans have a six-wire connector designed to be plugged into a hub that was included in the bundle, along with a remote control to change the light shown performed by those LEDs. Most users just need to plug those fans into the included hub, but some users like myself want to bypass the hub and control each fan directly. For this audience, I present the fan connector pinout derived from an exploratory session on my electronics workbench.

Since this was reverse engineered without original design documents, I don’t know which side is considered “pin #1” by the engineers who designed this system. These connectors appear to be JST-PH, whose datasheet does point to one side as “Circuit #1”. But there’s no guarantee the engineers followed JST convention. To avoid potential confusion, I’ll call them only by name.

NameSystemComments
+12VFanHigh side of fan motor. Hub connects this wire directly to +12V power input.
Motor LowFanLow side of fan motor. Use a power transistor between this wire and ground to control fan speed.
GroundFan + LEDPower return for LED circuit and can be used for fan motor low side as well. Hub connects this wire directly to power input ground.
Data InLEDInput control signal for addressable RGB LED. Compatible with WS2812/”NeoPixel” protocol.
+5VLEDPower for LED circuit. Hub connects this wire directly to +5V power input.
Data OutLEDControl signal for addressable RGB LED beyond the end of LED string inside the fan. Useful for chaining multiple units together by connecting this wire to Data In of the next device in line.

Now that I understand its pinout, I will build my own control circuit to replace the default Asiahorse hub.

Roger Cheng

LCD Driver Pinout for Honda CD

After a few wrong turns, I think I have a good grasp of the interface for talking with the audio (CD player) portion of a Honda Accord dashboard. This circuit board also includes HVAC (heating/ventilation/air conditioning) controls, though I investigated only their knobs and ignored the electronics. This page is a summary of my investigation into interfacing with audio controls.

Electrical

There are at least three independent circuits present.

  1. Panel backlight using small incandescent (filament) bulbs with a blue cover. Draws 0.6A at14.4V DC.
  2. LCD backlight draws 0.2A at 14.4V DC.
  3. Digital communication with Sanyo LC75883 LCD driver chip, which is a 5V part. We can send data to control LCD segment display and use it to read data for most of the button presses.
PinLabelDescription
1LAMP+BPower for panel light bulbs, up to +14.4V relative to LAMP-RET.
2LAMP+BPower for panel light bulbs, up to +14.4V relative to LAMP-RET.
3LAMP-RETReturn for panel light bulbs.
4LAMP-RETReturn for panel light bulbs.
5LCDLAMP+BPower for LCD backlight, up to +14.4V relative to LCDLAMP-RET.
6LCDLAMP-RETReturn for LCD backlight.
7P-GNDGround.
8P-GNDGround.
9P-GNDGround.
10IS BUS FRAMEUnknown.
11IS BUS DATAUnknown.
12CD-LEDUnknown.
13IGN-DETUnknown. (Ignition Detect?)
14SWD-VDD+5V power supply for LC75883.
15D-GND(Digital?) ground.
16LCD-DIData in from LC75883 chip. (Wired to LC75883 DO pin.)
17LCD-DOData out to LC75883 chip. (Wired to LC75883 DI pin.)
18LCD-CLKLC75883 Clock.
19LCD-RSTLC75883 Resets when pulled to 0V. Pull to 5V for normal operation, do not leave floating.
20LCD-CELC75883 Chip Enable.
21ENC VOL-DNOne of two quadrature encoder phases for central audio control knob.
22ENC VOL-UPOne of two quadrature encoder phases for central audio control knob.
23EJECTNormally open, shorts to ground when “Eject” button is pressed.
24PW SWNormally open, shorts to ground when “Power” button is pressed.

Digital

All control for LCD segment and key scanning for most of the buttons are handled by a Sanyo LC75883 chip. It communicates with a Sany proprietary protocol called CCB (Computer Control Bus) that has some resemblance to I2C or SPI but is neither. It listens on address 0x42 for bits indicating which LCD segments should be active, and reports on address 0x43 indicating which buttons were pressed. I have an Arduino sketch (target device: AVR ATmega328P based Arduino Nano) that demonstrates how to interact with the LC75883. Pressing the “Mode” button will cycle between the basic “turn all segments on” program, a bit pattern “drawing” program, and an animated demo.

This Arduino sketch for this investigation is publicly available on GitHub.

Roger Cheng

Preliminary Pinout for Honda CD

I have a Honda in-dash CD (and HVAC) control board and I want to see if I can make its LCD work. After I melted through conformal coating over the Sanyo LC75883 LCD driver chip, I was able to get an electrical connection with my meter so I can test for continuity between the pins (that are too fine for me to solder) to something I can more easily work with. I quickly found that much of the CD player functionality is connected to a small black rectangular connector I noticed earlier. Not just the LCD driver chip’s data communication lines, but also the big central rotary knob and button.

There is a large degree of uncertainty here, because I didn’t find what all of the pins did. I also found two pins that both appear to be ground, and I don’t know if there’s an important distinction between those two pins. This incomplete understanding explains the problems I will encounter later.

Using the numbers on the circuit board silkscreen, the pins are 1 to 24 from right to left. (Silkscreen shows 1 in the upper right, 2 in the lower right, 23 in the upper left, and 24 in the lower left.)

PinPreliminary NameDescription
7Vss (?)Either 7 or 9 is ground, maybe both?
9Vss (?)Either 7 or 9 is ground, maybe both?
14Vdd+5V power supply
16DOCCB Data Out
17DICCB Data In
18CLCCB Data Clock
20CECCB Chip Enable
21AEncoder A, connects to ground when knob is at certain positions.
22BEncoder B, connects to ground when knob is at certain positions.
24ButtonConnects to ground when “AUDIO PWR” button is pressed

Once these connections were made, I could make further progress. That is, running into an entirely different set of headaches.

Roger Cheng

Pinout of LCD Salvaged From AT&T CL84209

When I retired my landline phone connection, I also retired my home phone. It was an AT&T CL84209 phone with built-in digital answering machine. I had a base station and though it supported multiple cordless handsets I had just a single handset. Without a landline, I took the entire system apart keeping a few parts for potential later use. Among the stuff I kept were two custom LCD units. One LCD was freed from the base station circuit board. I wanted to keep its backlight as well, but I accidentally destroyed it while trying to free it from the system. The other LCD was in the handset, and I kept it attached to its circuit board because I didn’t want to accidentally destroy another backlight.

They sat in my pile of salvaged parts for several years, until a few weeks ago when I took them out and started playing with them. I thought I could find some official documentation on these display units, but nothing came out of searches using every identifier I could find on these devices. Fortunately, thanks to the still-working handset circuit board and a logic analyzer, I figured out enough to control them from an ESP8266 Arduino program. This page is a summary of my findings.

Electrical

Both LCDs have nine hardware interface connections. Base station LCD uses pins, handset LCD shown above uses an FPC. I’ve numbered them 1 through 9 counting left to right as we are looking at the display. Despite the different physical form factor, electrically speaking they respond identically.

PinNameAdditional Notes
1EnableWe can make it always enabled by tying it high: use a 1kΩ pull-up resistor connected to pin 5 (+3.3V)
2SCLI2C clock logic level measured +3.3V, don’t know if it is +5V tolerant.
3SDAI2C data logic level measured +3.3V, don’t know if it is +5V tolerant.
4GroundRelative to pin 5
5VccSupply +3.3V to this pin.
0.82uF capacitor between this pin and pin 6 (Vboost)
6VboostOutput pin of built-in boost converter. Measured at +5.4V.
0.82uF capacitor between this pin and pin 5 (Vcc)
7VLCDHLCD segment voltage (high) 8kHz square wave from Vcc to Vboost
0.82uF capacitor between this pin and pin 8 (VLCDL)
8VLCDLLCD segment voltage (low) 8kHz square wave from 0V to Vcc
0.82uF capacitor between this pin and pin 7 (VLCDH)
9Voltage measured to match Vboost
Appears not connected to anything else on handset circuit board.

Digital

Both LCDs are I2C devices with an address of 0x3E. There are two types of messages:

  • Configuration set of 8 messages. Values were copied from logic analyzer capture and played back. Their exact meanings are unknown.
  • Data set of 3 messages. First message includes 15 bytes of alphanumeric data for the first line, second message for the second line, and the third message has 16 bits of digital data toggling state of custom LCD segments. (Which are different between LCDs.)

See the following pages for details:

Source code of software written to help with this investigation is publicly available on GitHub.

Roger Cheng

Pinout of Tape Deck Faceplate (Toyota 86120-08010)

It is time to wrap up investigation into the workings of a tape deck faceplate, salvaged from the stock audio head unit of a 1998 Toyota Camry LE. I believe I’ve deciphered all the information necessary to reuse this faceplate independently from the rest of the tape deck. Summarized in this pinout report with links to more details.

The faceplate circuit board is largely built around a Sanyo LC75853N chip, which communicates via a Sanyo proprietary protocol called CCB (Computer Control Bus). An external microcontroller (I used an Arduino Nano in experiments to date) can dictate what is displayed on the LCD (see segment map here) and scan pressed/not-pressed state of buttons (see button map here).

Some faceplate components are independent of LC75853N:

From right-to-left, functionality I observed on these pins are:

LabelFunction
ACC5VPower supply for digital logic.
+5V relative to GND
LCD-DOCCB digital data out.
LC75853N address 0x43
Single 4-byte transmission to microcontroller.
LCD-DICCB digital data in.
Microcontroller to LC75853N address 0x42.
Three 7-byte transmissions to LC75853N.
LCD-CLKCCB clock signal.
Active-low generated by microcontroller.
LCD-CECCB enable.
Active-high generated by microcontroller.
CD-EJEEject button.
Normally open, shorts to GND when “Eject” button is pressed.
ILLIllumination power supply (positive).
+5V to +14.4V (~60mA) relative to ILL- for variable button backlight brightness.
LCD-BLLCD backlight power supply (positive).
+6V (~60mA) relative to BL-
VOL.CONVolume control potentiometer.
Voltage between ACC5V (full clockwise) and GND (full counterclockwise)
PULS-AAudio mode quadrature encoder knob – A
ACC5V or GND, will be opposite of B when at a detent.
A and B briefly identical during transition between detents.
PULS-BAudio mode quadrature encoder knob – B
ACC5V or GND, will be opposite of A when at a detent.
A and B briefly identical during transition between detents.
GNDDigital logic power (negative).
Relative to ACC5V
ILL-Illumination power supply (negative)
Relative to ILL
BL-LCD backlight power supply (negative)
Relative to LCD-BL
RESETUnknown. Observed 0V relative to GND.
LC75853N has no reset pin.
Seems OK to leave it unconnected/floating.
Unknown. Observed 0V relative to GND.
Seems OK to leave it unconnected/floating.

Source code for this investigation (and accompanying demo) is publicly available on GitHub.

Roger Cheng

Sleuthing NEC VSL0010-A VFD Control Pinout

Vacuum Fluorescent Display (VFD) technology used to be the dominant form of electronics display. But once LEDs became cheap and bright enough, they’ve displaced VFDs across much of the electronics industry. Now a VFD is associated with vintage technology, and its distinctive glow has become a novelty in and of itself. Our star attraction today served as display for a timer and tuner unit that plugs into the tape handling unit of a Canon VC-10 camera to turn it into a VCR. A VFD is very age-appropriate for a device that tunes into now-obsolete NTSC video broadcast for recording to now-obsolete VHS magnetic tape.

Obviously, in this age of on-demand internet streaming video, there’s little point in bringing the whole system back to life. But the VFD appears to be in good shape, so in pursuit of that VFD glow, salvage operation began at a SGVHAK meetup.

NEC VSL0010-A VFD Before

We have the luxury of probing it while running, aided by the fact we can see much of its implementation inside the vacuum chamber through clear glass. The far right and left pins are visibly connected to filament wires, probing those pins saw approximately 2.5V AC. We can also see eight grids, each with a visible connection to its corresponding pin. That leaves ten pins to control elements within a grid. Probing the grid and element pins indicate they are being driven by roughly 30V DC. (It was hard to be sure because we didn’t have a constant-on element to probe…. like all VCRs, it was blinking 12:00)

This was enough of a preliminary scouting report for us to proceed with desoldering.

NEC VSL0010-A VFD Unsoldering

Predating RoHS solder that can be finicky, it was quickly freed.

NEC VSL0010-A VFD Freed

Now we can see its back side and, more importantly, its part number which immediately went into a web search on how to control it.

NEC VSL0010-A VFD Rear

The top hit on this query is this StackExchange thread, started by someone who has also salvaged one of these displays and wanted to get it up and running with an Arduino. Sadly the answers were unhelpful and not at all supportive, discouraging the effort with “don’t bother with it”.

We shrugged, undeterred, and continued working to figure it out by ourselves.

NEC VSL0010-A VFD Front

If presented with an unknown VFD in isolation, the biggest unknown would have been what voltage levels to use. But since we have that information from probing earlier, we could proceed with confidence we won’t burn up our VFD. We powered up the filament, then powered up one of the pins visibly connected to a grid and touched each of the remaining ten non-grid pins to see what lights up. For this part of the experiment, we got our 32V DC from the power supply unit of a HP inkjet printer.

We then repeated the ten element probe for each grid, writing down what we’ve found along the way.

NEC VSL0010-A VFD Annotated

We hope to make use of this newfound knowledge in a future project, and we hope this blog post will be found by someone in the future and help them return a VFD to its former glowing glory.