MikePinball Posted November 28, 2018 Share Posted November 28, 2018 I am a fairly accomplished builder of electronic circuits. I am in the process of creating and eventually building a Pin2DMD display using the great technology developed by lucky1 and others. The displays, Nucleo-144 and mounting frame are fixed. The area I am focusing on is the Shield. Given that I am going to order some anyhow, why not take the opportunity to improve on the design if possible . One area of concern is the Micro SD. Instead of trying to find the exact header board, why not solder a Micro SD socket directly to the shield with a resistor array. There are a couple of choices here: SMD socket (which doesn't bother me but may other people who are worried about SMD soldering) Through-hole socket such as the Yamaichi PJS008U-3000-0 ($0.82 from Mouser). The only problem is that it is vertical and would require placement so it is not under the Nucleo. What do you think of using a socket for the Micro SD card? Are there other enhancements people would like? MikePinball Link to comment Share on other sites More sharing options...
Content Provider lucky1 Posted November 29, 2018 Content Provider Share Posted November 29, 2018 Hi Mike, our shields are designed for people with basic or almost no soldering skills. That is why we did not use any SMD parts for it. The waveshare microsd unit we use with the Nucleo board should be widely available. For a more professional look we designed the EVO boards. Feel free to modify / improve any of our designs. From my side the next step will be to design a EVO version of 192x64 and 128x16 but I currently don´t have the time to finish that. If you want to help, feel free to contact me. Link to comment Share on other sites More sharing options...
MikePinball Posted November 30, 2018 Author Share Posted November 30, 2018 Lucky1 - I understand where you are coming from and it makes sense. I put an append on PIN2DMD.COM but I will repeat it here. Creating large custom PCBs for each different form factor ala EVO is one way to do it. Alternatively you could create one custom "piggy-back" board and then three or more different plastic frames depending on how many and what size DMDs you wanted to use. Also that way someone can supply a set of built PCBs ready to go. I was going to start from the 128x32 design but I notice there are several differences between it and the shield: Shield uses STM32F429 whereas EVO uses the STM32F427. There are some differences between the uC function although I don't know if that makes a difference i.e. the software handles it or simply doesn't matter. For the DMD G0 signal, the shield uses the PE7 versus the EVO which uses PE1. Because it has more function (and the right size PCB 100mmx100mm), I think the shield might be the better place to start and then add in the 429 uC and support circuitry to create the piggy-back. BTW I notice there is one very minor error on the shield. One of the nets is not connected. It is one of those very small connections that electrical gets connected anyhow so no-one sees a problem. It is the SD_D02 signal over the hole for Micro SD card: MikePinball Link to comment Share on other sites More sharing options...
Content Provider lucky1 Posted November 30, 2018 Content Provider Share Posted November 30, 2018 2 hours ago, MikePinball said: Shield uses STM32F429 whereas EVO uses the STM32F427. There are some differences between the uC function although I don't know if that makes a difference i.e. the software handles it or simply doesn't matter. Makes no difference for our usage 2 hours ago, MikePinball said: For the DMD G0 signal, the shield uses the PE7 versus the EVO which uses PE1. Both boards use 100% the same pinout and code. PE7 is not used on the Nucleo shield as far as i can see. 2 hours ago, MikePinball said: I put an append on PIN2DMD.COM but I will repeat it here. Creating large custom PCBs for each different form factor ala EVO is one way to do it. Alternatively you could create one custom "piggy-back" board and then three or more different plastic frames depending on how many and what size DMDs you wanted to use. Also that way someone can supply a set of built PCBs ready to go. Doing it the EVO way was simply cheaper than costs for Shield+Nucleo+Acryl Frame and IMHO looks more professional in the end. Your approach could work well for 192x64 and 128x32 but for 128x16 you also need the DataEast DMD controller parts on the PCB. Link to comment Share on other sites More sharing options...
Content Provider lucky1 Posted November 30, 2018 Content Provider Share Posted November 30, 2018 3 hours ago, MikePinball said: One of the nets is not connected. It is one of those very small connections that electrical gets connected anyhow so no-one sees a problem. It is the SD_D02 signal over the hole for Micro SD card: Thanks for finding that one . Had to look twice to recognize what you are talking about. ? Link to comment Share on other sites More sharing options...
MikePinball Posted November 30, 2018 Author Share Posted November 30, 2018 1 hour ago, lucky1 said: Both boards use 100% the same pinout and code. PE7 is not used on the Nucleo shield as far as i can see. I looked again and indeed it is PE1 on the shield. My mistake. MikePinball Link to comment Share on other sites More sharing options...
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