Wrong flash size read if chip is DEBUG_LOCKED

[ReDetection]

Hello again.

According to the cc_info output, my CC2541 chip has 16kb flash (looks similar to #1). In the datasheet however it's stated only 128kb and 256kb versions and markings on the chip itself tell me I have 256kb.

What is recommended way to find, verify and fix the issue?

[ReDetection]

(output of cc_info)

INFO: Found a CC2541 chip on /dev/cu.usbserial-A70051tV

Chip information:
      Chip ID : 0x4113
   Flash size : 16 Kb
    Page size : 2 Kb
    SRAM size : 1 Kb
          USB : No

Device information:
 IEEE Address : 000000000000
           PC : 0000

Debug status:
 [ ] CHIP_ERASE_BUSY
 [ ] PCON_IDLE
 [X] CPU_HALTED
 [ ] PM_ACTIVE
 [ ] HALT_STATUS
 [X] DEBUG_LOCKED
 [X] OSCILLATOR_STABLE
 [ ] STACK_OVERFLOW

Debug config:
 [ ] SOFT_POWER_MODE
 [ ] TIMERS_OFF
 [ ] DMA_PAUSE
 [ ] TIMER_SUSPEND

[ReDetection]

OK, according to datasheet:

When the debug-lock bit, DBGLOCK, is set to 0 (see Table 3-5), all debug commands except CHIP_ERASE, READ_STATUS, and GET_CHIP_ID are disabled. The status of the debug-lock bit can be read using the READ_STATUS command (see Section 3.3.2).

So that explains why I got only chip id and statuses. After chip erase (./cc_write_flash.py --erase with any hex in the --in= parameter, even dump from ./cc_read_flash.py would work just fine) everything is back to normal and reporting correct flash size 🎉

I think maybe it's a bad idea to try to read some particular register out of the chip if it's known to be debug locked. Would suggest to early exit if it's debug locked.

[skandragon]

It might be nice if there was a way to do this through the command, like --erase --empty-flash or something.