I decided to start making some changes to the DeviceBus experiment. Basically I squeezed the function up in the right corner. Next I will replace RS232 with 2 x RS485 and add a LoRa or maybe Wifi and LoRa. I have little usage for Wired Ethernet on mobile devices, but I do lack radio options.
I have a version of XPortHub that works fine, so I have not been in any hurry to make this 2. unit with Ethernet, but I will finally order the PCB’s. XPortHub is very simple as it is only a switch between USB, CAN, RS485, RS232 and Ethernet. But, that exact functionality is what I…
This illustration show the 6 signals currenty used for “Device Bus”. The 3 first are a standard SPI in Half Duplex mode. That means that one device is Half Duplex Master driving the clock and sending on MOSI, while the others send/receive on MISO. The extra signals are designed to assist in deciding whom becomes…
I decided to change XPortHub2 due to parts of the layout – I need to use SPI 1 for “Device Bus” due to speed on F405, but the paths was crossed with Ethernet SPI and USB, meaning I had high frequency signals close without any isolation. I decided to re-route that part and add the…
I needed a board to test the new Device Bus/Watchdog so I stripped a XPortHub2 and added the logic that can be seen in the top right corner. It occupies almost 1/4 of the board so it does require some space. I need to work on that to find an optimal layout/solution. I am considering…
This is the schematics for Device-Bus, current sensor and power switch. I have a stripped down XPortHub that I might use for testing – removing W5500 leaves plenty of space without digging into 2nd side and 4 layer design. I simply would like to make some boards, put them in a stack and test for…
I was in the middle of planning a 8 pin bit-bang bus as my attention was drawn to STM32G070KB that cost 0.7 USD, comes in a LQFP32 package and contains: 2 x 1Mbps I2C, 2 x 32Mbps SPI, 4 x 6Mbps USARTS, 128Kb Flash, 32KbSRAM, running at 64Mhz and 7 DMA channels. Looking at the…
STM32L011F4 only have 16Kb Flash, and as I generate the code I need from STM32CubeIDE it compiles to 11,37Kb on Debug, leaving only 4,63Kb Free for the application. Looking at the map I see several nasty C functions n the drivers. The GCC compiler is decently good and greedy on bytes, but that don’t help…
This is the block diagram for XPortHub2 with an added Watchdog/D-bus. My objective here is that I want to add some features to the board and decided to do an experiment adding an external Watchdog/D-Bus by using a smaller STM32 in support. SPX3819 can be switched on/off enabling me to power a board on/off. Adding…