Search found 13 matches

by jcmvbkbc
Wed Jul 11, 2018 4:47 am
Forum: ESP8266 SDK
Topic: GDBStub throws exception
Replies: 2
Views: 571

Re: GDBStub throws exception

Bernard wrote:The only thing I can imagine is that this function is at a location you are not authorized to write and this will generate the exception...

It's because IRAM may only be read and written in aligned 32-bit words, but the failing instruction attempts to write 16 bits.
by jcmvbkbc
Wed Oct 18, 2017 2:01 pm
Forum: ESP8266 SDK
Topic: vsprintf, vsnprintf
Replies: 8
Views: 5513

Re: vsprintf, vsnprintf

smbgaiden wrote:I have nonOS SDK 2.1 with the xtensa includes from https://github.com/esp8266/esp8266-wiki ... nclude.tgz and using the crosstool-NG

You should be able to find stdarg.h in the crosstool-NG build directory: xtensa-lx106-elf/lib/gcc/xtensa-lx106-elf/4.8.5/include/stdarg.h
by jcmvbkbc
Thu Sep 14, 2017 4:05 am
Forum: ESP8266 SDK
Topic: os_printf with a char pointer parameter causes an exception
Replies: 3
Views: 1315

Re: os_printf with a char pointer parameter causes an exception

static void ICACHE_FLASH_ATTR someCb(const char *data){ os_printf( "LED = %s", *data); } Fatal exception 28(LoadProhibitedCause): epc1=0x40245abe, epc2=0x00000000, epc3=0x40246461, excvaddr=0x00000023, depc=0x00000000 ÿ ets Jan 8 2013,rst cause:2, boot mode:(1,6) The call to os_printf sho...
by jcmvbkbc
Mon Apr 27, 2015 11:43 am
Forum: ESP8266 HDK
Topic: Strange slow access to I/O registers
Replies: 3
Views: 3518

Re: Strange slow access to I/O registers

I even tried just to repeat the same write instruction (at the same offset) with identical results. I thought it could be "address/offset" related but it's not. There is no difference in just doing s32i %0, %2, 0 s32i %0, %2, 4 s32i %0, %2, 8 s32i %0, %2, 12 ... or s32i %0, %2, 0 s32i %0,...
by jcmvbkbc
Mon Apr 27, 2015 10:06 am
Forum: ESP8266 HDK
Topic: Strange slow access to I/O registers
Replies: 3
Views: 3518

Re: Strange slow access to I/O registers

It seems like some sort of "cache overrun" but the statement "ESP has no caches" is everywhere in the forum(s)... Looks more like memory-mapped hardware doesn't allow faster writes. But apart from it you're using the following sequence: "l32i.n %0, %2, 0 \r\n" "s3...
by jcmvbkbc
Sun Mar 08, 2015 1:45 am
Forum: ESP8266 SDK
Topic: Precise timing needed (ex. for IR decoding)
Replies: 16
Views: 16746

Re: Precise timing needed (ex. for IR decoding)

As a side note, you can have up to twice as fast GPIO control if you specify -mno-serialize-volatile in gcc flags. Oh? Using what GPIO control method? I tried your recommendation and I'm still doing 6 mhz outputs; no changes. See: http://imgur.com/FzdnY5X Sorry, brain fart. CPU is obviously fast en...
by jcmvbkbc
Sat Mar 07, 2015 3:31 pm
Forum: ESP8266 SDK
Topic: Precise timing needed (ex. for IR decoding)
Replies: 16
Views: 16746

Re: Precise timing needed (ex. for IR decoding)

As a side note, you can have up to twice as fast GPIO control if you specify -mno-serialize-volatile in gcc flags. Oh? Using what GPIO control method? I tried your recommendation and I'm still doing 6 mhz outputs; no changes. See: http://imgur.com/FzdnY5X Changing GPIO registers directly. Without -...
by jcmvbkbc
Sat Mar 07, 2015 5:06 am
Forum: ESP8266 SDK
Topic: Precise timing needed (ex. for IR decoding)
Replies: 16
Views: 16746

Re: Precise timing needed (ex. for IR decoding)

Maybe there is a better way to control low level timer through registers, etc, but dont see any good documentation on this yet - I would like to know too ;) You're using the SDK's GPIO_INPUT_GET function which is quite slow. Direct register usage for read/writes is explained here: http://www.esp826...
by jcmvbkbc
Fri Mar 06, 2015 12:58 am
Forum: ESP8266 SDK
Topic: Precise timing needed (ex. for IR decoding)
Replies: 16
Views: 16746

Re: Precise timing needed (ex. for IR decoding)

@jcmvbkbc do you know how much / when overflow ( register bit ) can read , too? have me a interupt for this? can we trigger this? I'm not sure what you're asking, my guess is the questions are - how long is CCOUNT SR? -- it's 32 bits - is overflow of CCOUNT detectable? -- no, there's nothing that c...
by jcmvbkbc
Sat Feb 14, 2015 8:48 pm
Forum: ESP8266 SDK
Topic: Precise timing needed (ex. for IR decoding)
Replies: 16
Views: 16746

Re: Precise timing needed (ex. for IR decoding)

Is there any way to get an interrupt at 50us resolution or to get a tick count at 50us resolution? You can read CCOUNT special register. It increments every clock tick, i.e. every 12.5ns with 80MHz clock. You can read it with the following function: static inline unsigned get_ccount(void) { unsigne...

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