Thunderbolt Monitor Kit Manual v5.0.6
Page 9
3/8/2020
Thunderbolt. The Thunderbolt simulator does not emulate all the functionality of the
Thunderbolt, it only emulates some of the functionality supported by the kit.
The connections are as follows:
Kit
Function
PC serial port
(DB-9)
J1-1
5
J1-2
3
Using a different display:
As mentioned earlier, the kit can drive different kinds of displays as long as they use a
Hitachi HD44780 interface chip or compatible. Some users may want to use larger LCD
devices while others may prefer a Vacuum Fluorescent display (VFD). The kit was
designed to make this not only possible but easy. There are several notes of caution
related to using a different display.
1) Power consumption:
The kit has a 250mA rated 5V low dropout voltage
regulator on board (U4) for the LCD, and a similar but separate 3.3V voltage
regulator (U7) for the CPU and WiFi module. It is important not to exceed the
current rating or the power rating of the regulators. The regulators are mounted
on lands of copper planes acting as heat sinks, with sufficient power dissipation
capability to support operation with the default display with supply voltages as
high as 12V, but the regulator may overheat when driving larger displays,
particularly if powered from a supply voltage near the top of the range. Therefore
it is recommended to reduce the maximum supply voltage, particularly when
driving larger displays. The kit will work fine with as low as 5.5V supply (when
measured at the kit’s J1 connector).
2) VFD displays:
Some VFDs may draw more current than LCDs and may exceed
the power dissipation capability of the built-in regulator U2. If using a VFD, make
sure you select a VFD with 150mA maximum current consumption.
3) Contrast adjustment:
When using a different type of LCD, the contrast may
have to be readjusted. Note that the adjustment range is fairly narrow and it is
quite possible that replacing the LCD with another may initially give absolutely no
visible information. That is normal, simply power up the kit and adjust R6 until the
display contrast is satisfactory. VFDs typically do not use the contrast
adjustment.
4) Backlight:
When using a different LCD display, the backlight resistor R7 may
have to be adjusted or bypassed. Refer to the display’s datasheet for more
information. VFDs typically do not use the backlight inputs.
5) Header:
The kit uses a 0.1” spaced 16 pin, single row header to connect to the
display. Compatible headers are available from a wide variety of sources.
6)
Mounting:
The standard LCD is mounted on the kit’s PWB using standard
threaded male-female standoffs (metric size). When using an alternate display,
you may have to devise a different mounting arrangement as the mounting holes
may not line up.
