Before handling the hardware, one must understand the naming convention:
reset_config srst_only srst_nogate init_target echo "E7A V3 Link engaged. Holding nSRRT for 50ms." adapter assert srst sleep 50 adapter deassert srst
Once the link is active, you can dump the onboard flash:
openocd -f interface/jlink.cfg -f target/e7a.cfg -c "init; dump_image e7a_firmware.bin 0x08000000 0x100000; shutdown"
Replace addresses based on your e7a’s memory map. e7a mb pcb v3 link
For full register access and boundary scan, the V3 link reverts to 5-pin JTAG. This is used when:
How to switch modes: The V3 link header includes a detection resistor on pin 9. A 4.7k resistor between nSRST and GND forces JTAG mode; an open circuit defaults to SWD.
Use this flowchart-style checklist:
The E7A MB PCB V3 Link supports two operational modes. Understanding which mode your specific E7A variant uses is critical.
flash bank e7a_main efi 0x08000000 0x80000 0 0 $TARGETNAME
Why did the engineers move to V3? Here is a technical retrospective: Before handling the hardware, one must understand the
| Feature | E7A V1 Link | E7A V2 Link | E7A V3 Link | | :--- | :--- | :--- | :--- | | Header Pitch | 2.54mm (standard) | 1.27mm (high density) | 1.27mm with keying | | Voltage | 5V only | 3.3V only | 2.8V – 3.3V (auto-sensing) | | Max Speed | 500 kHz | 4 MHz | 1 MHz (stability fix) | | Reset Handling | External pull-down | Shared with power seq | Dedicated line with V3 glue logic | | Security Fuse | None | Weak (reset bypass) | DBG_LOCK (titanium grade) | | Common Failure | Bent pins | Broken retention clip | Capacitor C149 failure |
Verdict: V3 trades raw speed for reliability and security. It is harder to probe but less likely to corrupt flash during debugging.