Hi,

I am using Segger JLink Base version with JLink software V6.32D. I am trying to flash board AcSip S76S, its an SOC containing STM32L073RZ (192K flash + 20K RAM) controller with Semtech LoRa modem. I can connect to target, executed few register reads and writes to allow disable read out protection, but I am not able to access internal RAM either through command "Read 32bit" or if I try to enter programming (blank check, erase or flash). I am executing command through JFlash, below are logs when trying to read internal RAM through command "Read 32bit":

Connecting ...
- Connecting via USB to J-Link with SN 58006798
- Target interface speed: 1334 kHz (Fixed)
- VTarget = 4.995V
- Executing init sequence ...
- Executing Reset (0, 0 ms)
- Executing Write 32bit (0x4002200C, 0x89ABCDEF)
- Executing Write 32bit (0x4002200C, 0x02030405)
- Executing Write 32bit (0x40022014, 0xFBEAD9C8)
- Executing Write 32bit (0x40022014, 0x24252627)
- Executing Write 32bit (0x40022018, 0x00000F00)
- Executing Delay (1 ms)
- Executing Write 32bit (0x1FF80000, 0xFF5500AA)
- Executing Delay (1 ms)
- Executing Delay (100 ms)
- Executing Delay (100 ms)
- Executing Write 32bit (0x40022004, 0x00040000)
- Executing Delay (100 ms)
- Executing Read 32bit (0x20000000)
- ERROR: Could not read target memory
- ERROR: Failed to connect.
Could not perform custom init sequence.

And below are logs when I try to do blank check:

- Connecting via USB to J-Link with SN 58006798
- Target interface speed: 1334 kHz (Fixed)
- VTarget = 4.917V
- Executing init sequence ...
- Executing Reset (0, 0 ms)
- Executing Write 32bit (0x4002200C, 0x89ABCDEF)
- Executing Write 32bit (0x4002200C, 0x02030405)
- Executing Write 32bit (0x40022014, 0xFBEAD9C8)
- Executing Write 32bit (0x40022014, 0x24252627)
- Executing Write 32bit (0x40022018, 0x00000F00)
- Executing Delay (1 ms)
- Executing Write 32bit (0x1FF80000, 0xFF5500AA)
- Executing Delay (1 ms)
- Executing Delay (100 ms)
- Executing Delay (100 ms)
- Executing Write 32bit (0x40022004, 0x00040000)
- Executing Delay (100 ms)
- Initialized successfully
- Target interface speed: 1334 kHz (Fixed)
- J-Link found 1 JTAG device. Core ID: 0x0BC11477 (None)
- Connected successfully
Blank checking target ...
- 1542 of 1542 sectors selected, 2 ranges, 0x8000000 - 0x802FFFF, 0x8080000 - 0x80817FF
- Start of preparing flash programming
- ERROR: Failed to download RAMCode.
- ERROR: Failed to prepare for programming.
Failed to download RAMCode!
- End of preparing flash programming
- ERROR: Failed to check blank target
Disconnecting ...

Attaching .JFlash for reference. This is my first time programming SOC based STM32L0 controller. Let me know if I am missing something.

Thanks,
Harsha

Hi,

Thanks for the reply. I created the init sequence taking the example from wiki.segger.com/STM32.

To this sequence I added additional command to set watchdog to software in FLASH_OPTR register. AcSip module is powered by USB, only SWD lines of JTAG are connected to target board. JTAG pins 1 and 19 are shorted to simulate VTref. Target power supply is set VTGT in Project settings -> Production -> Power source, I will change this to 'NONE' and try again.

Regards,
Harsha

Hi Nino,

Thanks for the tip. VTref was indeed the problem, from AcSip module I pulled a 3.3V signal and connected to pin 1 of Jlink and everything went fine (Project settings -> Production -> Power source = VTGT). Please close the thread.

Regards,
Harsha