BRTRO-420 Reflow Oven Better Blazin' Modification - Page 1
Forum section: electronics / general

author: bleckers
author_rank: Contributor
timestamp: June 18, 2019, 03:17:46 pm
content: Edit: this has turned into a thread about modifying the reflow oven with a mod board as detailed here -https://hackaday.io/project/167324-brtro-420-better-blazin-modFrom thistopicTassiloH mentioned that there might be a possible serial interface for the BRTRO-420, since it doesn't come with one as standard.Quote from: TassiloH on August 25, 2018, 10:58:46 amHaving recently received one of these myself, I decided to go straight for the COM port to see what's going on, as it would be nice to at least have some temperature readouts.The board itself uses a CY96610 Series CY96F613 microcontroller - The datasheet for this is here -https://www.cypress.com/file/232341/download, technical reference manual here -https://www.cypress.com/file/241411/download,more documents here -https://www.cypress.com/products/16fxTo get the ball rolling, I have reverse engineered the "COM" port connection. See attached for the schematic of this.Unfortunately connecting to either the TX output or R25 to a scope doesn't output any data when the unit is switched on, or when sitting on the main page. The next step is to build a USB/UART adapter to power up the RX optocoupler and try sending commands to it.If I cannot get anywhere with this, I might consider decoding the LCD outputs and interfacing with the buttons to control it. The LCD is a standard 128x64 dot matrix LCD with model number 12864D1 V3.0 (could be the same as this with a KS0108, KS0107 chipset -http://www.vishay.com/docs/37329/37329.pdf) and the buttons wired to a separate board. There's no markings on the other side of the LCD PCB.Stay tuned!Edit:Looking at the Cypress datasheet, header W1 is connected to DEBUG I/F with a pullup which is the one wire debug interface. When the DEBUG I/F and MD pins are held low on reset (MD is tied to ground and the other side of W1 is ground), it enables serial programming on USART2 (and USART7,USART8). According to the datasheet, USART2 uses SIN2-Pin7 SOT2-Pin8 and SCK2-Pin9 for programming, however on this board the SCK2 pin is used elsewhere, so I'm pretty sure the COM header isn't used for serial programming, as you'd expect SCK2 to also be connected through (this alleviates some doubt I had about it possibly being just a programming interface).Edit 2:I connected this up to a USB->UART adapter and cycled through all possible serial speeds and settings. Unfortunately there is no response even though the signal gets through the optocoupler (although it's inverted on the output compared to the TX pin, so it might need something else). Considering this board has a 420 label on the speaker sticker, I'm guessing this board is a generic controller, with custom firmware depending on the board.Edit 3:Reading further into the technical reference manual, the third USART connection for SCLK is actually not required for serial programming (see page 892, Figure 31-4). So it could very well be that this COM port is in fact a flash programming connector...Edit 4:I'm not really willing to mess with the DEBUG I/F and put this into serial programming mode, in case I brick the firmware. Instead I'm going to create an adapter to interface with the LCD and decode the menu from that information.Edit 5:After hooking up a logic analyser to the display, I can confirm that it is infact a KS0108 with the same interface/pinout as the vishay display linked above (it seems most of these LCDs follow the same pinout order at least for the data pins).

author: ar__systems
author_rank: Frequent Contributor
timestamp: June 20, 2019, 01:47:36 pm
content: Fairly inefficient use of time. Why do you want to reverse the trivial function, when it is much easier to rewrite the s/w from scratch. Let alone doing for a very bad oven...

author: bleckers
author_rank: Contributor
timestamp: June 21, 2019, 05:33:58 am
content: Quote from: ar__systems on June 20, 2019, 01:47:36 pmIf I had a spare controller or a cypress dev kit lying around, I'd totally give this a crack. The main reason I don't want to do this is that I have to effectively brick it (I'd of course remove the original micro to keep it from being completely bricked) and go all in with the software rewrite path, whereas decoding the LCD allows me to still use the machine while debugging. I also have to still figure out what the LCD is anyway to be able to talk to it.The machine itself is decent enough in terms of temperature management (compared to the other cheapies out there), so there's nothing to really gain from a reprogram, apart from a native com port. Decoding the LCD on the other hand can be useful for other machinery that uses the same LCD and it's a passive modification.

author: bleckers
author_rank: Contributor
timestamp: June 22, 2019, 01:25:35 pm
content: So I created a quick KS0108 parser that decodes the output from a logic analyser CSV file.The logic analyser is connected to an additional 10x2 header that I attached to the LCD cable (see attached). The pinout is the same as the Vishay datasheet on this machine.I was going to make a passthrough adapter so it didn't require any modification, but that would require etching a board up to connect to all the double row traces. Doing it this way, I can now just put a connector in the center of a bit of veroboard and connect up a small controller board to all the required pins.I have a small NRF52 board laying around, so the next step is to wire this up, port the decoder code to it and send it over BluetoothEdit: Attached is the current version of the decoder software (.NET 4.0) with an example CSV file to display. The CSV file is exported from the Saleae Logic software, but any similar format will work fine.Edit 2: I'm continuing the project here on another page -https://hackaday.io/project/166220-domsnif-dot-matrix-lcd-sniffer-bluetooth-adapter

author: bleckers
author_rank: Contributor
timestamp: November 03, 2019, 10:32:07 am
content: Just an update on this reflow oven for anyone interested. While the LCD decoding was a novel undertaking, I actually ended up recreating an entire controller mod for the oven since the original firmware was still pretty garbage. It works extraordinarily OK (for an IR oven) now.You can read about it all over here -https://hackaday.io/project/167324-brtro-420-better-blazin-mod

author: ubbut
author_rank: Regular Contributor
timestamp: November 05, 2019, 08:41:59 am
content: Hi,this looks great! And since I unfortunately have a BRT-420 I'd be very interested in modding mine as well.Are you planning to release the final board files, code (and maybe instructions) in a zip file or on github?

author: bleckers
author_rank: Contributor
timestamp: November 05, 2019, 12:33:08 pm
content: They're all on githubhttps://github.com/bleckers/brtro-420-better-blazinI'm slowly getting all info together to make this easy to reproduce, but by all means shoot me a message if you need some help. The current PCBs I have require a few mods to get things working (otherwise I'd offer them to you), but the gerbers on the github page have all the changes required. I have spare components and will be making a PCB order in the coming days, so I can tack a new batch of these onto the order and build some up if you are interested.The firmware is...a bit how ya doing, but it works. I will clean it up at some point if I get the time, but it was mostly just an evolution of testing code.

author: ubbut
author_rank: Regular Contributor
timestamp: November 05, 2019, 01:09:31 pm
content: Very cool!Will order the boards myself, guess that is easier than importing them from Australia. But thanks for the offer!Working firmware is all that's needed

author: bleckers
author_rank: Contributor
timestamp: November 05, 2019, 01:17:20 pm
content: No problemo!Hopefully most of it is straight forwardish. I haven't written a step by step how to, so you'll have to fill in some of the gaps, but everything should be there.I just noticed there is missing silkscreen on Q1 and Q2 (these parts can also be any PNP SOT23 transistor as long as it has the same pinout). I can update this tomorrow for you if you like.

author: ubbut
author_rank: Regular Contributor
timestamp: November 05, 2019, 01:18:57 pm
content: No worries, thanksWon't order this for a few days, but will combine it with the next PCB orderLooking forward to this, the oven has been a PITA

author: bleckers
author_rank: Contributor
timestamp: November 05, 2019, 01:39:53 pm
content: I've found this oven unusable since day one (I kind of half expected to have to mod it a bit, I just didn't realise the microcontroller was so obsolete). I've been using my old modified toaster oven still.This mod makes the menus much nicer to use and it actually does some of the work for you if you mess up a profile a bit (i.e. it will catch up to the next stage temp before moving on).I actually have been quite impressed with it since the mods (I'm still tweaking and playing with it to get it just right, but no more underflowed or scorched PCBs so far). This might just be the best IR oven out there now.

author: ubbut
author_rank: Regular Contributor
timestamp: November 05, 2019, 01:43:20 pm
content: Quote from: bleckers on November 05, 2019, 01:39:53 pmThat's the number one worst thing of the original firmware. (Apart form the horrible menuI am using it with some complete non-sensical parameters I found by trial and error and it works for small production runs (kind of).

author: bleckers
author_rank: Contributor
timestamp: November 06, 2019, 01:03:56 pm
content: Changes made. I actually swapped the PNP/resistor inverters out with a typical SOT23-5 inverter gate. This inverter was omitted from the original design, but it turned out that the optocouplers for the serial connection on the original controller inverted their output in the config they are wired in, so I bodged one in on my mod board.I used a PNP/resistor based inverter as that was what I had on hand, and replicated that in the mod board design, but it really isn't optimal. So it's been swapped out now with a much better alternative now.

author: ubbut
author_rank: Regular Contributor
timestamp: December 03, 2019, 08:20:42 am
content: The kit from @bleckers arrived yesterday. Will install it as soon as there is time and post results here..