Printer Model: 3d printer
MCU / Printerboard: BIQU111-A7 klippy.log
Describe your issue:
I detached this motherboard from my BIQU Magician 3D printer. It came from 2018 and I couldn’t find any information about it on the Internet.
Here is some information I know about this motherboard:
Carry LPC1768 chip
The original firmware is Smoothieware
Have a USB interface and convert UART to USB
Has an AUX interface, once used to connect screens
Now I want to flash the klipper firmware into this motherboard, and I have successfully compiled klipper.bin. After renaming klipper.bin to firmware.bin, I copy it to the SD card and insert it into the motherboard. It can be seen from Flash Magic that I have successfully flashed into klipper firmware, but the fluidd shows that I can’t connect. I guess it’s a klipper.bin problem
Some additions:
I tried to use Flash Magic to flash klipper.hex (converted from the klipper.bin file with a starting address of 16 KiB), but I still couldn’t use it.
When I flash in the original firmware with Flash Magic, I can receive the boot information through the serial port. However, when klipper.hex is flushed in, no messages are received
The some files are provided, including the following:
Yes, firmware.bin was renamed FIRMWARE.CUR after I unplugged the SD card from the motherboard. And whenever I use Flash Magic to flash in the firmware, I notice if the bootloader still exists
Thank you for your suggestion, I will try to flash canboot.bin
When I use Smoothwareware firmware, I can receive startup information from the serial port. But when I use the Klipper firmware, I cannot receive any information.
Is this a normal phenomenon?
I have an LPC1769 in one of my printers as well. It works pretty much standard as detailed above. No need for Flash Magic etc, except for updating the bootloader if wanted.
It seems that the mainboard in the document is different from mine. My board only has boot pin (ISP pin). But I’m sure I know how to use the SD card to flash in the firmware, because I can successfully use the SD card to flash in the original firmware.
I seem to have found the problem, which seems to be the problem of the board itself
I flashed in Smoothieware again and connected the original TFT2.8 host computer so that the board can work properly. But when I connect to the computer using usb-ttl, I can receive the boot information of Lpc1768 through the serial port, but LPC1768 does not respond to the information I send.
Schematic Diagram of TFT2.8 Upper Computer： TFT28-SCH.pdf (63.4 KB)
From the schematic diagram above, I guess I might need an RS232
Through the ChatGPT conversation, it seems that it can explain why LPC1768 did not respond to the information I sent.
RS232 and TTL-USB are compatible when receiving information through a serial port. The reason why the message cannot be sent to LPC1768 is that TTL-USB cannot use - 3V.
I do not think that this statement is correct or relevant to our case here since this very much depends on the electrical layout of the board and the used components like level shifters, logical buffers etc.
Reading through this, I think there needs to a reset on what “RS-232” is and why you’re looking in the wrong direction. It is highly unlikely that the board you have is working with what is now called a “UART”, although the more correct term would be “NRZ serial” which works with traditional logic levels.
RS-232 is something of an ancient standard that goes back to literally the 1950s and uses, common for the day, much higher voltage swings (with one side negative as in the referenced quote) than would be contemplated today. It was very commonly used in the 1980s and started fading out in the 1990s with the advent of USB with it being almost unheard of today except in industrial settings. It also uses a connector that which is quite unique for today and will look something like:
I can’t find any references to any 3D printer controllers that have RS-232 on them and, I’m very certain something going back to 2018 would not have an RS-232 interface.
Now, I’m confused about your original description as you say the board has an LPC1768 on it and this has a built in USB but you say there is a USB interface and “convert UART to USB”. How do you know this is the case?
The schematic link you attached to a recent post (TFT28-SCH.pdf) does have the letters “RS232” attached to J1 but I can assure you that it’s not RS-232, it’s a UART with only positive logic levels.
It sounds like you’ve burned Klipper into your 2018 LPC1768 controller board but cannot connect to your controller. Can you confirm that this is correct and please describe (ideally with pictures) how you are trying to connect the two systems. What are you using as the printer controller (Raspberry Pi or other), are you connecting using USB or a UART and what is the wiring?
The confusion is chatGPT. It can only give answers according to the question. @Elect: To make a long story short
RS-232 and serial TTL are both serial protocols, i.e. one data bit after the other
RS-232 range from 3V to 15V but in both directions, e.g. -13V to +13V
Serial TTL ranges from 0V to VCC, which can be either 3.3V or 5V in typical modern TTL electronics
UART (Universal Asynchronous Receiver-Transmitter) is strictly speaking a piece of hardware that speaks such a serial protocol
USB to TTL is again a piece of hardware that translates from the much more complex USB protocol to the simple serial protocol (always in both directions)
Nowadays RS-232 is quite seldom, the older folks amongst us remember it from the beginning of the internet where the first modems were attached via RS-232 (hell, am I really that old?!?)
