[Verified] EV2400 Standard Edition Original Factory Solution with Isolation

Project Introduction:
          The EV2400 is an official debugger from TI, designed to replace the EV2300 for BQ series battery chargers, fuel gauges, and battery protection chips. These chips can communicate with the EV2400 via I2C/SMB/DQ buses. The EV2400, in conjunction with the BQStudio host software, completes the basic chip settings before the chip can be used normally. Therefore, the EV2400 is an indispensable tool for BQ series chip development.
          DJI drones and some laptop batteries from various manufacturers also use BQ series fuel gauges for battery protection and power monitoring; however, under certain circumstances, such as prolonged dust accumulation, accidental short circuits, or replacement of battery cells, the fuel gauge may detect undervoltage/overcurrent/open circuit in the battery pack, causing the battery pack to lock up and become unusable. To restore normal operation in this case, besides going to after-sales service, it is necessary to use the EV2400 to reconfigure the relevant registers of the fuel gauge and unlock the battery pack.
          Since the official TI EV2400 is prohibitively expensive (price as of writing, see image)
          , fortunately, TI has released the EV2400 schematic, allowing us to purchase a relatively inexpensive one on Taobao/Xianyu. Alternatively, if you prefer not to be priced too high or enjoy tinkering, building your own is a good option. This project provides a verified, well-protected, original-factory-compatible, compact, and aesthetically pleasing DIY EV2400 solution.
Construction Process:
1. Schematic Design:
          TI has released the EV2400 schematic, which mainly includes three parts: data conversion, level conversion & interface protection, and level settings. TI's official solution uses the MSP430F5529 microcontroller for data conversion, currently priced around 25 RMB on Taobao, which is acceptable and represents the majority of the cost of this debugger. (The image shows a 5529 chip for 23 yuan on Taobao.)
(Note: Some people online have also found that the F5528 (average price around 10 yuan) can be used as a substitute, and there are related solutions. However, I have also verified this. I bought four chips from different stores, and they either had no core voltage, the crystal oscillator didn't oscillate, or they could only be flashed but couldn't run. There are too many bad products. I spent 40 or 50 yuan on chips but didn't get a single usable one. It's better to just use the 5529, at least genuine ones are easier to find.)
24/9/20: The 5528 version has been completed and is now open source. Open source address: [Verified] EV2400-Lite based on F5528 [Not recommended for replication] - LCSC Open Source Hardware Platform (oshwhub.com).
It should be noted that due to the high price of genuine chips and the rampant refurbished and scrap chips on the market, it is not recommended to use the 5528 for this purpose. The specific reasons are in the open source link. In TI
 
          's official solution, an adjustable linear regulator is used in conjunction with Renesas' digital potentiometer to achieve an adjustable reference level, matching the debugger signal level with the IC's internal signal level. (In reality, it's not a perfect match. After testing, it was found that for the BQ4050, its internal logic level should be 1.8V, but the debugger uses 3.1V as the reference level (as shown in the figure).
 
For the BQ27542, its reference level is even closer to 3.2V (as shown in the figure).
However, it's worth noting that some unofficial sources I consulted stated that a non-adjustable reference level (such as the fixed 3.3V reference level used in most lightweight EV2400s on the market) might damage the chip being debugged. However, in my humble opinion, TI, as one of the world's leading analog chip design and manufacturing companies, would certainly consider various application environments. Moreover, the internal block diagram of the chip provided by TI (using the BQ4050 as an early representative) shows that the chip's data interface uses a logic gate buffer circuit between the internal CPU (as shown in the figure)
, and in many designs, the MCU with a 3.3V reference level communicates directly with the battery protection chip without any chip damage observed. ) In the worst-case scenario, furthermore, according to the recommended operating conditions in section 6.3 of the BQ4050 datasheet, the maximum withstand voltage for the SMC and SMD interfaces is 26V (as shown in the figure).
Meanwhile, another TI battery fuel gauge and protection chip, the BQ40Z80, integrates a lightweight EV2400 on its EVM. The official schematic shows that its interface does not use a level conversion IC with the fuel gauge IC interface, but only a few pull-up and pull-down resistors (as shown in the figure). Research indicates that the BQ40Z80's internal CPU also uses a 1.8V power supply, indicating that it has internal level conversion circuitry and can operate at 3.3V. Therefore
, the conclusion that cheap debuggers/fixed reference level debuggers will damage the chip, and the assertion that some debuggers made with the 5528 chip are defective and can damage the chip (the specific reasons are explained in this project: [Verified] EV2400-Lite is based on F5528 [Replicating is not recommended]) The conclusion regarding the LCSC open-source hardware platform (oshwhub.com) may be a deliberate misrepresentation by vendors to justify higher prices. The debug level of TI's official debugger is almost identical to 3.3V; the cheaper debugger lacks features like series current and electrostatic discharge (ESD) protection. For drone enthusiasts/developers looking to save costs, cheaper debuggers are perfectly usable, though they come at the cost of lacking protection. While
 
          other features can be compromised, protection is a crucial function for debuggers, especially since they may be dealing with battery packs of several or even dozens of cells. A single incorrect connection could cause a series of circuits to malfunction. Sparks can cause damage, even to the computer; therefore, protection features are essential. This solution, based on the original manufacturer's design, includes comprehensive ESD and overcurrent protection. The data interface uses a combination of PTC and TVS diodes to prevent incorrect wiring from causing a crash. A USB and power isolation module has also been added. Although it cannot reach the chip's nominal value of 2.5KV, it is sufficient to prevent the battery voltage from leaking into the computer's USB port. Of course, if you think a cheap USB isolator is too expensive, an alternative solution is provided: soldering a 0-ohm 1206 resistor will allow you to use a pass-through mode.
2. PCB Design:
           The same board type as the previous J-Link V9 Base was used, so the casing file can be used with minor modifications (actually, it's just laziness []~(￣▽￣)~* (slacking off, so satisfying!)). The direct-output design means that the USB socket, debugger, and debug cable are all in a straight line, taking up less space. (If you're interested in the J-Link V9 Base, here's the link: [Verified] Protected, High-Quality J-Link_V9_Base - LCSC Open Source Hardware Platform (oshwhub.com))
(A side note: while browsing the MSP manual recently, I found some tutorials from TI on porting STM chip programs to MSP series microcontrollers—poaching ST's talent, haha!) It's true what they say, red and blue are a perfect match! ヾ(≧▽≦*)o) Since
the 3.3V power supply is mainly used as a reference level and space is limited, an LDO was used instead of a DC-DC converter to provide 3.3V.
3. Soldering & Debugging & Assembly:
          There's not much to say about this; component selection and soldering are basic skills. I just recommend soldering the level conversion chip, F5529, and digital potentiometer first, otherwise it will be difficult to use the soldering iron later. Those who use this will definitely be familiar with these things, so I won't go into too much detail. (Here are some pictures taken during the soldering process:)
Solder paste applied but not yet heated on the hot plate:
Finished product after soldering:
However, I still have to mention a few things about component purchasing:

MSP430F5529IPNR Purchase Link: MSP430F5529
Level Shifter Chip Purchase Link: ST2329AQTR (Speaking of which, TI has quite a few level shifter chips themselves. I don't know why they insist on using ST's, and they're also very difficult to solder.)
Digital Potentiometer Purchase Link: ISL90842UIV1427Z
USB Interface Isolator Purchase Link: ADUM3160
Protection Diode Array Purchase Link: TPD4E05U06DQAR

The above components are only from my purchase channels, provided solely for DIY convenience. I do not guarantee the lowest price; they only indicate that the components were usable at the time of my purchase and are not intended as promotion.
 
Debugging – Firmware Download (Important!!!)
        If the chip you receive is new, it will not have an internal program. If it's a salvaged chip, it will have an unnecessary program. You can't just buy an eZ-FET to download a program just to build an EV2400, right? Don't worry, TI provides a more convenient method – downloading via the MSP430F5529's USB-BSL mode.
        Simply put, this mode is equivalent to redefining the pins used for SWD in STM32. To download the program again, you can only do so by setting the microcontroller to UART download mode during a reset using high and low levels on BOOT1 and BOOT0, and then burning the program through the UART1 port. The MSP430F5529 will detect the level of the USB-PUR pin during a reset. If it's pulled high, it enters USB-BSL mode, reports itself as a USB device, and reports its specific VID and PID. The host software detects the microcontroller's presence by checking the VID and PID and performs a full erase and write of the new program via USB. With
        the theoretical analysis complete, here are the practical steps:

First, download the EV2400 updater from the TI website (currently the latest version is 0.32), or you can download it from the firmware section at the end of this article. After downloading, as shown in the image: Right-click and select "Run as administrator." After installation, a "TI" folder will appear on your C drive. Locate the folder "EV2400Updater-0.32" inside. The first file in the folder is your programming program . However, if you directly open it, you'll find it says it doesn't find the EV2400. This is normal; your EV2400 hasn't been programmed yet. We need to pass parameters to this program so it knows to program a chip that doesn't have a program. Right-click the program, select "Create Shortcut," then right-click the created shortcut, click "Properties," and in the "Target" field, type a space after it, then enter "-s." Click " Apply" and then "OK." Now, plug your soldered EV2400 into your computer and press the button slightly to the left of the center of the board. Next comes the important part: While holding down the reset button, immediately release it. You should hear a device connection beep on the computer, but no new device will appear in Device Manager, indicating that the computer has recognized the chip. Double-click the shortcut you just created, and the software should indicate that it is erasing. The computer will then beep to indicate that the device has been inserted. After the software finishes running, unplug and replug the chip or press the reset button again. The computer will beep again to indicate that the device has been inserted, and the software will display the following, with all three indicator lights lit, indicating that the programming is complete. (Note: If you hold down the button for a long time, the computer will also beep to indicate that the device has been inserted and will display an unknown device. This is normal and can be ignored. Just start the process again; it is not a hardware or chip problem.) Then, go to the official website to download or download the BQStudio installation software from the attachment. After downloading and installing, insert the EV2400 with the programmed software and open BQStudio. When you open it, you will be prompted to select the target chip to debug. Select any one for now. After entering, the upper left corner will display the currently connected debugger and its software version, as shown in the figure. (If you connect the chip you want to debug before turning it on, it will be automatically recognized, no selection is needed) (The image below shows manual chip selection) OK, at this point, the EV2400-Standard is complete. Go and enjoy the battery unlocking or the jail-like debugging!

Shell Assembly:
        If you don't want your debugger to be exposed, usable shell files are provided in the attachment. It is recommended to use an FDM 3D printer with a 0.2mm nozzle (0.4mm is also acceptable). Use a soldering iron to insert an M2 3mm outer diameter, 3mm high thermosetting nut, and use an M2_8mm long countersunk screw. For specific operations, please search "3D printing thermosetting nut", which will not be elaborated here; an identification diagram is also included. Find a printing shop and have them print the diagram at a size of 32*80mm (note the unit!!!), then stick it on the top cover, and you're done!
(This light is so bright, haha! A larger current-limiting resistor or a black casing would probably be better.)
(The light is slightly smaller in the picture because I told the seller a specific size, but she still chose automatic scaling to fit. (Laughs, if you can scale it however you want, guess why I told you a fixed size?))
Regarding the attachments:
          The attachments are software related to the EV2400, as well as some unlocking passwords and techniques, collected from the internet and given away for free; accuracy is not guaranteed, you'll need to try them yourself (will be updated periodically). Don't forget to bookmark or give it a free like! (。・∀・)ノ
Due to some software being too large to upload from LCSC, I had to use Baidu:
Link: https://pan.baidu.com/s/12k6vG-GeNx7NKa42GbXFbw?pwd=6699 Extraction code: 6699
 
Update log:
2024/9/21 - First release