topic Re: Pointer to register in Kinetis Microcontrollers

Pointer to register

ricardcomas — Fri, 12 Apr 2019 08:19:37 GMT

Hello everyone.

I'm using MCU KE04 series and I want write a register of CPU

For instance, the KBI0_PE (Pin Enable Register) can be found in 0x40079000 absolute address so, Can't i do this?

//////////////////////////////////////////////////////////////////////// CODE ////////////////////////////////////////////////////////////////////////

static const uint32_t BASE_ADDRESS_KBI0 = 0x40079000; //Base address
uint32_t *pointerRegister = NULL; //Initialization

pointerRegister = (BASE_ADDRESS_KBI0 + 8); //points to location fo KBI0_SC (40079008h)
*pointerRegister = 0xFEFFFFFF; //¿Write register?

//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

it frozen MCU, why?¿

Re: Pointer to register

jingpan — Fri, 12 Apr 2019 09:31:19 GMT

Hi,

The valid register address of KBI0 is from 0x40079000 to 0x40079002, Only 3 byte. 0x40079008 is out of range. When MCU find valid address access, it will trig hardfault.

Regards,

Jing

Re: Pointer to register

ricardcomas — Fri, 12 Apr 2019 09:56:07 GMT

Hi mate, thanks fro your asking,I just tried to acces 0x4007900, but i can't write it yet, Is it possible have i use the BME (Bit Manipulation Engine) module for access?

Re: Pointer to register

mjbcswitzerland — Fri, 12 Apr 2019 11:28:02 GMT

Hello Richard

Before accessing the KBI registers you need first to enable the KBI in SIM_SCGC.

Both enabling the clocks to the module and subsequent mode writes can be performed using the BME but this is not your basic issue.

Regards

Mark

Complete Kinetis solutions, training and support:http://www.utasker.com/kinetis.html
Kinetis KE:
- http://www.utasker.com/kinetis/FRDM-KE02Z.html
- http://www.utasker.com/kinetis/FRDM-KE02Z40M.html
- http://www.utasker.com/kinetis/FRDM-KE04Z.html
- http://www.utasker.com/kinetis/FRDM-KE06Z.html
- http://www.utasker.com/kinetis/FRDM-KE15Z.html

Re: Pointer to register

ricardcomas — Fri, 12 Apr 2019 12:05:45 GMT

Hi mate, thanks for your answer, That's work! it has been fixed! :smileyhappy:

Thank everyone!

Re: Pointer to register

mjbcswitzerland — Fri, 12 Apr 2019 13:36:37 GMT

Note that to enable the clock via BME the following can be used:

*SIM_SCGC_BME_OR = (SIM_SCGC_KBI0);

which on the KE04 is

*(volatile unsigned long *)(0x40048000 + 0x0c + 0x8000000) = 0x01000000;

Regards

Mark

Re: Pointer to register

ricardcomas — Tue, 21 May 2019 12:29:53 GMT

Could you explain me how does BME work? why do you add "0x0c + 0x8000000" to "0x40048000" ?¿¿

Re: Pointer to register

mjbcswitzerland — Tue, 21 May 2019 18:32:38 GMT

Richard

The starting address of the SIM module is 0x40048000
The byte offset in the SIM module to the SIM_SCGC register is 0x0c, therefore its memory address is (0x40048000 + 0x0c).

The BME OR alias is an address shift of 0x80000000 therefore the OR alias of this register is at the address (0x40048000 + 0x0c + 0x80000000).

To OR 0x01000000 to the register one writes 0x01000000 to its OR alias, which gives the complete instruction.

Similarly, to AND one uses an alias offset address of 0x40000000 instead of 0x80000000, and to XOR one uses an alias offset address of 0xc0000000.

Details are also in the BME chapter of the user's manual.

Regards

Mark

Complete Kinetis solutions for professional needs, training and support:http://www.utasker.com/kinetis.html

uTasker: supporting >1'000 registered Kinetis users get products faster and cheaper to market

Re: Pointer to register

ricardcomas — Wed, 22 May 2019 10:57:10 GMT

Hi Mark

mm but in the datasheet tell this:

The offset's 0x14,isn't?

Re: Pointer to register

mjbcswitzerland — Wed, 22 May 2019 11:33:20 GMT

Richard

It depends on which KE04 you are using:

MKE04Z8VTG4(R), MKE04Z8VWJ4(R) and MKE04Z8VFK4(R) are at 0x0c

MKE04Z64VLD4(R), MKE04Z128VLD4(R),MKE04Z64VQH4(R), MKE04Z128VQH4(R), MKE04Z64VLH4(R),MKE04Z128VLH4(R), MKE04Z64VLK4(R) and MKE04Z128VLK4(R) are at 0x14

The user should not be fussed with the details if a macro is used. In the uTasker project it adapts itself automatically by

#if (defined KINETIS_KE04 && (SIZE_OF_FLASH > (8 * 1024))) || defined KINETIS_KE06 || (defined KINETIS_KEA64 && !defined KINETIS_KEAN64) || defined KINETIS_KEA128
..
#define SIM_SCGC_BME_OR (volatile unsigned long *)(SIM_BLOCK + 0x14 + BME_OR_OFFSET)
..
#else
..
#define SIM_SCGC_BME_OR (volatile unsigned long *)(SIM_BLOCK + 0x0c + BME_OR_OFFSET)
..
#endif

And the user just does

POWER_UP_ATOMIC(0, KBI0);

which transforms itself automatically to the corresponding BME code

which then works on any Kinetis part with KBI.

Non uTasker users have to carefully read the manuals and add the corresponding code manually.

Regards

Mark

Complete Kinetis solutions for professional needs, training and support:http://www.utasker.com/kinetis.html
Kinetis KE:
- http://www.utasker.com/kinetis/FRDM-KE02Z.html
- http://www.utasker.com/kinetis/FRDM-KE02Z40M.html
- http://www.utasker.com/kinetis/FRDM-KE04Z.html
- http://www.utasker.com/kinetis/FRDM-KE06Z.html
- http://www.utasker.com/kinetis/FRDM-KE15Z.html
uTasker: supporting >1'000 registered Kinetis users get products faster and cheaper to market

Re: Pointer to register

ricardcomas — Wed, 22 May 2019 11:38:28 GMT

Okey, I get it!

Thanks for you time mate!

Regards