Hi,

First, i would say a big thanks for your job, like because i can to concretize an old dream.
I am making a MCP panel and I have realised a PCB with all fucntion for a Zibo 737.
All works except the 74HC595 for the led buttons (ex NAV, F/D, VOR LOC...)

I have used your schema at the end of this page:

https://simvim.com/tech/reg_595.png

but, the led don't bright. 

My question is, on your schema, there is a red point on the SRCLR pin but no wire, so I don't have solder this pin. I must to solder with the VCC (+5V) or not?

For more information, i have connected the 74HC595 to PIN 4 of the arduino (SIG) and the L and D bus.  In the configurator, on the pin 4, I use LED Driver with 1V for  "Volts - below this bus volatage the display is OFF"

Thank you very much for your response.

Olivier

closed with the note: 74HC595 replaced and now all work!!! thanks!
in Wiring, Powering by

3 Answers

0 votes

Hi astrolivier76

response is yes, you must connect pin # 10 directly to VDD +5 Volts, if this pin is not connected the 74HC595 does not glow the segments. This video is seven segments with 74HC595, but it works just like an announcer.

https://www.youtube.com/watch?v=Vg_xNlAHbgQ

Milton Rodriguez.

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Hi,

Thanks for your response.

last night I soldered the pin 10 to VCC (+5V) but the led don't bright.  I have tested with my voltmeter and i found that :

- VCC - GND = 5V -> OK
- pin 10 (SRCLR) - GND = 5V -> OK
all pin OUT (Qa Qb... QH) = 0V -> not OK ( in the simulator led is ON)

So, I have tested the electric continuity with my multimeter and i found a problem:  when i tested between the cathode of the led and the ground i found a continuity, ad I think that the problem is that the led is in short -circuit.

what do you think?

My PCB have two 74HC595 connected with the QH' of the first and SER of the second, but i have solder only the first, but when I test the second (just between the drills of my pcb) I don't found continuity between cathode and ground. Do you think that my 74HC595 is dead?

Can you help me please!

thanks
Olivier
0 votes

Oliver,

First, the "red dot" on the diagram means this  chip leg should be in high logical level (or just connected to 5v (if not TTL chip is used).
I have corrected  the diagram.

Regarding your problem, it looks like you could possibly connect your LEDs in wrong direction. The cathode should be on ground.

Check this.

note: you can't simply use a multimeter to check your circuit with diodes/LEDs and active components (ICs). And especially on working circuit. Measure a voltage is useless.  Only an oscilloscope is useful.
Vlad

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Thank you Vlad,

I tested the circuit when it's not powering, except for the two measures of 5V.

So, now that my pin 10 is connected to the 5V and that the led don't bright, I have verified the sens of the led (cathode to the ground and anode to the resistor and it's OK, all seems good

In order to see better, I join a draw of my schematic and a PDF of my pcb.

Also, I can to give a gerber file if you want to inspect my file.

thank you very much

link for DOC and image from my drive

0
Sorry, but I don't have time to dig into complex PCb layouts.

It's all simple, and I don't quite undestand why do  you need a united PCB at all in you home MCP? It's not serial production, just one module for you.

Regards,
Vlad
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In fact, the schema is very simple.

I will go to desoldering my 595 and test it with a breadboard.

There are several reason why I decided to make a pcb.

I want a panel where all components are easy to replace in case of failure.

also, i have another bigger project to build my astronomical observatory and using pcb will make my life easier.

that's why I wanted to first try on a simple project.

I understand that you do not have time to watch the whole pcb, but is it possible to just look at the plan for only the 74HC595?

thanks a lot

Oliver
0
Also, I have put the "data.cfg",

may be there is an error when I use the configurator :/

sincerly thanks.

Oliver
0 votes

I put here the code of the data.cfg file...if a good soul can tell me if this is good

tks.

Oliver

------------------------------------------------------------------------------------

*1-1U1

[Devices]

N2.0 D=0 B=1,10 b=0

N2.1 D=0 B=1,10 b=0

N2.2 D=0 B=1,10 b=0

N2.3 D=0 B=1,10 b=0

N2.4 D=0 B=1,10 b=0

N2.5 D=0 B=1,10 b=0

L4 D=5 B=1,10 b=0

[Input]

B3.0 AT_Thrust_Hold

B3.1 AT_SPD_Hold

B3.2 AP_FLCH

B3.3 AP_LNAV

B3.4 AP_HDG

B3.5 AP_LNAV

B3.6 AP_NAV

B3.7 AP_ALT_Arm

B3.8 AP_VSI

B3.9 AP_CMD_A

B3.10 AP_CMD_B

B3.11 AP_CWS_A

B3.12 AP_CWS_B

S3.13 AT_Arm_Switch

S3.14 AP_FD_1_Switch

S3.15 AP_FD_2_Switch

E5.0 AP_HDG_Set

E5.2 HSI_Sel_CRS

E5.4 AP_SPD_Set

E5.6 AP_ALT_Set

E5.8 AP_VS_Set

E5.10 HSI2_Sel_CRS

B6.0 AP_APP

B6.1 AP_All_Disengage

B6.2 ALT_INTV

B6.3 SPD_INTV

[Output]

N2.0 HSI_Course o=3

N2.1 HSI2_Course o=3

N2.2 AP_SPD_Cmd o=3

N2.3 AP_ALT_Cmd o=3

N2.4 AP_VS_Cmd o=3

N2.5 AP_HDG_Cmd o=3

L4.0 AP_NAV_On

L4.1 AP_APPR_On

L4.2 AP_ALT_On

L4.3 AP_VS_On

L4.4 AP_CMD_A_On

L4.5 AP_CMD_B_On

L4.6 AP_CWS_A_On

L4.7 AP_CWS_B_On

L4.8 AP_FD1_MA

L4.9 AT_Arm_On

L4.10 AT_Thrust_On

L4.11 AT_SPD_On

L4.12 AP_FLCH_On

L4.13 AP_VNAV_On

L4.14 AP_HDG_On

L4.15 AP_VNAV_On

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