| Electronics > Projects, Designs, and Technical Stuff |
| Adding many UARTs to an existing system |
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| oPossum:
12 pins if an address latch is used. 8 data, /RD, /WR, /CS, /ALE The peripherals in a MCU are generally going to be much cheaper than any external solution. |
| brabus:
Bitbang them like there's no tomorrow. |
| jeremy:
I also thought of that, but the main microcontroller is already quite busy, and most of the data is RX heavy at 115200 baud. I think I’m just going to buy one of these MCUs with a large number of UARTs and roll my own, it really seems like the easiest option at this point. |
| David Hess:
--- Quote from: jeremy on June 11, 2019, 03:56:27 am ---I have an existing microcontroller system with only one spare UART, but I need 5 of them. It seems like there are some chips on the market for this (SPI/I2C to UART), but they are more expensive than buying a second microcontroller... Has anyone solved this problem before and can point me in the right direction? I'm not able to multiplex the lines unfortunately, I really do need a FIFO-based system. --- End quote --- I have solved it before in the way you suggested. I used an inexpensive microcontroller with built in UART as a smart programmable UART. |
| Bassman59:
--- Quote from: jeremy on June 11, 2019, 03:56:27 am ---I have an existing microcontroller system with only one spare UART, but I need 5 of them. It seems like there are some chips on the market for this (SPI/I2C to UART), but they are more expensive than buying a second microcontroller... Has anyone solved this problem before and can point me in the right direction? I'm not able to multiplex the lines unfortunately, I really do need a FIFO-based system. --- End quote --- You don't say what microcontroller you're using, but if it has an external memory interface, you can connect a small FPGA to it through that interface and then get all of the UARTs you want. Expose each UART as registers in the micro's memory space. More expensive than buying another micro? Depends. Gotta do the engineering to determine that. Often the FPGA can do "other stuff" that might make your life easier. |
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