VDI-RODERICO

[chafik]

Why people still doing programme for old chip like 16f84 16f876 or 16f878 or 16f88 they are expensive and they will become obsolete because microchip is introducing new chip with big memory size and cheaper and have the new features microchip is doing that because they are going from assembly to c programming

[kroman01]

do not change the PCB will be pin + 8V and BAT will decide during construction what to choose ... LCD should be bought with white LEDs in the backlight, everything with a white LED has a maximum current of 20mA, which is too big because at night the eyes are tired and they should be toned down

[roderico]

that would be the option for the 78L05, it looks very nice. IMO it would be better to leave the 8V pin and make a little room for a 7805 since there is already a regulator in the idx for 8V, and in this way, the pcb can be used with both 12V/8V and with 78L05/7805 for compatibility

[kroman01]

displays have a bright background, so they do not require backlighting during the day, only at night do not have to be so bright, I am reducing the LED current of the R11 330R resistor. this is how the "Lugatek DM-1" shines the total current from the 12V 20.5mA power supply .... stabilizer 78L05 system on the ATMEGA8 A-PU 10 MHz clock

[roderico]

IMO a good choice would be 7805 with a heatsink if using 12V and without heatsink if using 8V

[roderico]

in the datasheet of the 78L05 the output current is < 100mA and the power dissipation < 0.7W it won't work well with the backlight...

[roderico]

according to the datasheet the supply current for the backlight is 150 mA, you need to add at least another ~10mA, then you will need to dissipate (12V-5V)*160mA = 1.12W with the 78L05 instead of 0.48W if using 8V

[kroman01]

I did vdi Lugatek DM-1 and V-Box 2 with the use of LCD AG-128064H-FHW K / W-E6 or EG-128064H-FHW K / W-E6 and enough 78L05 it all depends on the required current to LED backlight

[roderico]

depending on your LCD you might also need to replace the 78L05 by a 7805 if using 12V, you could test it in the new prototype for comparison

[roderico]

with 12V you willneed to dissipate more than twice the power that with 8V, produces moreheat, more noise… but maybe it is negligible for this

[roderico]

Compliments to the bold design ... my suggestions for changes will be given after the prototype and tests in IDX .... a good solution with this SW5 - you can use SW3 to turn on the backlight ... I do not want to power the system with + 8V only with BAT, in IMUT + 8V to be deleted, power the system with BAT

you only have to short pins 2 and 3 of P1 (input) while keeping the 5 pin input to use only 12V, did you use 12V in your current vdi?

[kroman01]

Compliments to the bold design ... my suggestions for changes will be given after the prototype and tests in IDX .... a good solution with this SW5 - you can use SW3 to turn on the backlight ... I do not want to power the system with + 8V only with BAT, in IMUT + 8V to be deleted, power the system with BAT

[roderico]

SW5 will be now pins 3 and 1 of Q1 in the new schematic, but any of SW1, 2 or 3 can be programmed to replace SW5

[roderico]

yes PIC16F886 would be sufficient to drive a LCD, however, if you would like later to upgrade to a GLCD (more expensive) then probably a pic with more memory would be necessary. I added a small change in the schematic following waltr's suggestion to include also sacchetti's backlight control for version 2 since there will be now plenty of memory and it would be compatible with an external switch. If you would like to do some tests, you could also use the sample prototype 80x53mm I have just made, it can be improved if there are suggestions, only missing to adapt the firmware...

[kroman01]

these schemes are final I can order PIC16F886 to perform prototypes to test in the field on my IDX