OLED display overview
The OLED display module is a high contrast, 256 x 64 pixel, white-on-black, graphic OLED (Organic Light Emitting Diode) display with a 3.12 inch (diagonal) screen. The OLED display was released in June 2018 for use with Tortuga Audio’s LDR.V25 (“V25”) LDR preamp controller board and V25 versions of Tortuga Audio preamps. The OLED display is also fully compatible with our latest ePot.V3 Max and Mini stepped attenuator/controllers and related V3 preamp products.
With release of the OLED display we discontinued using our earlier dual 7-segment displays. Most V25 based preamps with the earlier 7-segment displays can be upgraded to the OLED display. Please contact us to ask about upgrades.
The dimensions below are accurate for the front view. However, the side view does not include the adapter board which sits behind the display panel and is attached to the display panel via the 20 pin header. Designers should provide 1.5 inches of space to accommodate the overall depth of the display including the adapter board and its pin header.
Also, please note the IR receiver module (on left side of photo above) which mounts directly to the OLED display interface board. An additional 0.5-0.75 inches of space should be allotted for the IR receiver which needs to face outwards next to the display panel.
OLED display module
The OLED display is composed of several parts starting with the display module proper which is shown in the photo above along with its dimensions. The display module is a glass OLED screen attached to a green rectangular circuit board with a 20 pin interface header and mounting holes in each corner. A custom adapter board is mounted behind the main circuit board via the 20 pin header. The adapter board has a 14 pin header for connecting the OLED display to the preamp controller board via a ribbon cable.
The OLED display adapter board also serves as the mounting point for the IR receiver module (3 hole solder pads) and for connecting the encoder module (4 pin header). The current production Rev C OLED display routes the display signals, the power, and signals for both the IR receiver module and encoder module through the single 14 pin header & ribbon cable.
The are 3 versions of the OLED display (A, B & C) with C being the current production version. As there are also multiple versions of both the V25 and V3 controllers that use the OLED display it’s important to carefully examine the table below to assess compatibility.
OLED display versions & compatibility
| Criteria | OLED Version A | OLED Version B | OLED Version C |
|---|---|---|---|
| OLED display interfaces | * 14 pin parallel - display signals only * 10 pin - for IR receiver and encoder signals only | * 14 pin serial SPI - display signals only * 10 pin - for IR receiver and encoder signals only | 14 pin serial SPI - for display signals, IR receiver and encoder |
| V25 - Rev A | Compatible | Not compatible | Not compatible |
| V25 - Rev B | Not compatible | Compatible | Compatible - requires IR receiver and encoder to be connected individually to V25.J3 header and not through the OLED display interface board |
| V25 - Rev C | No compatible | Not compatible | Compatible |
OLED ribbon cable
The OLED cable is a 2×7 IDC ribbon cable that connects the 14 pin OLED.J2 header on the display module and the corresponding OLED header on V25/V3 controller boards. The ribbon cable carries the following signals:
- 3V3 – power (clockwise)
- G – ground
- SC – SPI clock
- CS – SPI display select
- SW – encoder switch
- EB – encoder leg B
- RES – OLED display reset
- G – ground
- G – ground
- DC – OLED display data/command
- EA – encoder leg A
- IR – infrared receiver signal
- SO – SPI data
- LED – status/panel LED signal
- Data/Command
Please note that the ribbon cable connector ends are NOT keyed and thus can be connected in reverse. While this is unlikely to damage equipment, please be careful to make sure the red stripe on the ribbon cable is on the same side of each header that has a white dot the circuit board (i.e. align the red stripe with the white dot).
Encoder/IR cable
Version A used a second 2×5 IDC ribbon cable to carry encoder and IR receiver signals. This cable ran between the 10 pin V25.J3 header and the its corresponding 10 pin OLED.J3 header on the adapter board of the Rev A version of the OLED display module.
Versions B and C OLED displays do not use this cable.
Encoder module
A rotary encoder module (with integral push button) interfaces to the preamp controller board through the OLED display module. The encoder takes the place of a conventional front panel manual volume control knob. It also provides additional functions such as muting, power on/off, and input switching.
The encoder works by generating pulses as it turns. These pulses have a different pattern depending on whether the encoder is turned clockwise or counterclockwise. It generates 20 complete pulse sequences per revolution. Thus, for a 100 step volume control, you would have to rotate the encoder/knob 5 times to go from step 0 (mute) to step 100 (max volume). This is a different paradigm from a conventional volume pot where one revolution (or less) goes from 0 to max volume.
The ePot.V3 Mini has its own built-in encoder module. Do not connect a separate encoder module to the OLED display when using the ePot.V3 Mini. In doing so you will have connected 2 separate encoders to the V3 Mini which will either disable encoder operation or cause it to malfunction.
Encoder cable
A 4-wire square-pin type cable (or 4 separate square pin female-female jumpers) connects the rotary encoder module to the 4 pin OLED.J4 header on the display module adapter board. The pins are labeled EA, EB, ES & G on both the OLED interface board and the encoder module. This cable is used in all versions of the OLED display module.
IR receiver module
The 3-wire IR receiver module interfaces to the preamp controller board through the OLED display adapter board. It is soldered directly to the OLED display adapter board. The 3 pins are keyed such that the IR receiver module can only go in one way naturally. The IR receiver must be positioned such that it looks out into the room through the front panel as must the OLED display itself.
OLED interface with V25 controller
The interface between the OLED display module and the V25 controller board is shown below but without the actual cables present. The V25 board shown below is a version A board with the extra 10 pin J3 header for the IR/encoder power/signal connections. Version B and C boards do not have the J3 header and instead use the 14 pin J9 header for the IR/encoder power/signal connections.
The OLED display module shown above is a version A module with both the 14 pin and 10 pin headers. Version B and C modules only have the 14 pin header. All versions have the 4 pin encoder header. Also note the IR receiver soldered to the adapter board. The IR receiver is located immediately next to the front of the display and is oriented so that it looks forward and must be able to “see” into the room in order to receive commands from the Apple IR remote.
OLED interface with V3 controller
** coming soon **