Damaged DSP (TMS320LF2406A) on CNC Controller – Need Flash Recovery Advice - Page 1
Forum section: electronics / repair

author: adenbob
author_rank: Contributor
timestamp: September 09, 2025, 03:12:33 am
content: Hello all,I'm currently repairing a servo controller from a TL521 tabletop CNC mill, which drives all four axes via parallel port step/direction input. While modifying the mill, I accidentally shorted the A-axis motor conductor (+24V) with an encoder channel (+5V), which damaged two of the four servo channels.After some investigation, I found that the board contains two DSP TMS320LF2406A chips:U1: Handles the X and Y axes (still functional)U4: Handles the Z and A axes (suspected to be damaged)At present, the X and Y axes operate correctly, but any input to the Z or A axes triggers an encoder communication failure error.What I've Tried So FarI’ve already attempted one repair. Upon opening the controller, I found that it uses high-to-low buffers (CD74HC4050M) to step down the encoder signals from +5V to the DSP's I/O voltage of +3.3V. These buffers have an absolute maximum input voltage rating of +16V.Based on this, I replaced the U5 buffer chip, which was responsible for passing encoder signals (for Z and A) and the direction line of the step/direction signals to the DSP. Unfortunately, this did not resolve the issue. I now believe that the +24V short may have reached the DSP's encoder input pins and caused internal damage.Current FocusI’ve now shifted my attention to the U4 DSP chip itself. My goal is to read the program from its internal flash and write it to a replacement chip.So far, I’ve identified the pinout of the programming header (J2), which provides access to all the required signals per the datasheet—JTAG and strapping pins included.The ProblemWhat I’m struggling with is finding a viable toolchain to read from and write to the flash. TI’s documentation for this chip is extremely limited, and I’ve had no luck using the following:Code Composer Studio: I’ve tried every version back to 7.4, but cannot create a new project for the TMS320LF2406A. Unfortunately, TI no longer offers older Windows installer versions that might support it.C2Prog: Attempted, but didn’t have success.OpenOCD: I tried this as well, but lack the knowledge to configure it properly.My Main RequestI'm looking for help with the TMS320LF2406A toolchain, or any alternative method to recover and reprogram the DSP. If anyone has experience with this device, knows of working tools, or can recommend a way to dump and flash its firmware, your guidance would be hugely appreciated.Thanks in advance!board/chip info:U1 : TMS320LF2406A - X and Y axis DSP chipU2 : CD74HC4050M - buffer for X and Y encodersU3 : CD74HC4050M - buffer for incoming step signals for X, Y, Z, and Z axies and direction signals for X, and Y over the parallel portU4 : TMS320LF2406A - Z and A axis DSP chipU5 : CD74HC4050M - buffer for Z and A encoders, and direction signals for Z and AU6 : LMD18200T - X axis motor H-brige with integrated current sceneU7 : LMD18200T - Y axis motor H-brige with integrated current sceneU8 : LMD18200T - Z axis motor H-brige with integrated current sceneU9 : LMD18200T - A axis motor H-brige with integrated current sceneU10 : TPS7333Q - 5V to 3V3 supplyU11 : not populatedU12 : LM2574N-5 - 24V to 5V supply

author: fzabkar
author_rank: Super Contributor
timestamp: September 09, 2025, 03:46:06 am
content: https://www.ti.com.cn/cn/lit/ds/symlink/tms320lf2406a.pdfQuote

author: daisizhou
author_rank: Super Contributor
timestamp: September 09, 2025, 04:01:20 am
content: You can try xds100 or Signum jtagejet c2000

author: adenbob
author_rank: Contributor
timestamp: September 09, 2025, 04:17:03 am
content: to be clear, i have a j-link im just looking for the software tool chain.

author: amyk
author_rank: Super Contributor
timestamp: September 09, 2025, 04:20:34 am
content: Look for sprc074.zip.

author: coromonadalix
author_rank: Super Contributor
timestamp: September 09, 2025, 09:39:17 am
content: so hard to provide a linkhttps://www.ti.com/tool/download/SPRC074/01.00.00.00but it ask for a registrationhere are the 2 files inside the zip, they can be downloadedhttps://www.u-cursos.cl/ingenieria/2007/1/EL54D/1/material_docente/detalle?id=126741version.txt and the exe remove the dot txt extensionand the zipped sprc074.zip