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Recent content by ntsmkfob

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    Repurposing PIC16F877A 7 segment LED PCBs

    Thanks Mike. I'll try that tomorrow.
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    Repurposing PIC16F877A 7 segment LED PCBs

    Hopefully, once I get it actually displaying the data I'm sending, I can go back to the USB converters. The serial board needs a 12v supply, which is a pain. I was getting the framing errors on the output of the USB sticks.
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    Repurposing PIC16F877A 7 segment LED PCBs

    Hi, yes, I have to use RS485, as that is what the PCB has installed. It uses a MAX3082 to convert the RS485 to TTL. I tried the USB dongles you mention, the CP2102 and the FTD ones, they both were giving framing errors all the time. Once I get the PCB working with the serial PCB, I'll try them...
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    Repurposing PIC16F877A 7 segment LED PCBs

    Thanks for all your help! sagor1 was right about RC1. I now have the LEDs working, so moved on to getting the RS485 and UART side working. I wasted a lot of time trying to use USB to RS485 devices and just getting garbage, but finally got clean transmission using a USB to RS232 cable and an old...
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    Repurposing PIC16F877A 7 segment LED PCBs

    Thank you sagor1. As the display will only change every minute, it won't hurt to introduce a small delay in the toggling.
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    Repurposing PIC16F877A 7 segment LED PCBs

    Thank you for all your helpful replies. The 2 chips at the top of the photo are indeed 4511s, mislabelled as the PIC, due to my copy/ paste excesses! And of course I referred to bits in PortB as pins. However, With your advice I have created some code that turns on each LED with the appropriate...
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    Repurposing PIC16F877A 7 segment LED PCBs

    I've tracked the latch enable pins: led 1 - RD7, led2 - RD6, led 3 - RD5 and led4 - RC1. Pins 0 - 3 of PortB go to pins 7,1,2,6 on the HEF4511BCP and the other 4511s. Pins 4 - 7 of portB go to the ULN2004 driving power to the leds 1,2,3,4. I just don't know how to code this. Any help gratefully...
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    Repurposing PIC16F877A 7 segment LED PCBs

    Now I see that pin 5 on each 4511 has a resistor pulling it down to zero, but a track on the other side of the PCB running back under the LEDs, so I need to trace these back to their origins.
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    Repurposing PIC16F877A 7 segment LED PCBs

    You are both correct - the no 4 LED has a HEF4511BCP and the other 3 have a CD4511 each, together with a resistor array. I've now worked out that the 1 & 2 LEDs are driven using PORTD, and the 3 & 4 by PORTB. However, I don't understand why I don't have to send anything to PORTD other than...
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    Repurposing PIC16F877A 7 segment LED PCBs

    Here's the hex file, in case anyone can decode it.Just knowing the serial parameters and input layout might get me over the line. Thanks in advance. John
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    Repurposing PIC16F877A 7 segment LED PCBs

    Thanks for the reply. No logic analyser, but one on its way. With the original firmware in the PIC (proprietary so can't get the source, only the hex dump), it displays 0, off, colon, 0, 1 with the dip switches all off or 1 , 2 off and 3, 4 on , so I expect the dip switches are used to allow...
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    Repurposing PIC16F877A 7 segment LED PCBs

    I have a few PCBs that have 4 large 7 segment LEDs. They were countdown timers for squash courts. They use an RS422/RS485 feed to send them the value to display, and use a PIC16F877A to drive the LEDs through a ULN2004AN and a 4511 for each LED and 4116R-1 resistor arrays.. The Rx side of the...
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