bit-banding: base address for peripheral registers alias area?

[bob239955]

Posted on September 05, 2008 at 03:12

bit-banding: base address for peripheral registers alias area?

[bob239955]

Posted on May 17, 2011 at 12:43

The stm32f10xxx reference revision 5 page 37 section 2.3.3 'Bit-Banding' paragraph 2 says;-

''In the STM32f10xxx both peripheral registers and the SRAM are mapped in a bit-band region'' but there is no mention where the alias region begins for the peripheral registers. The ST, ARM and code documentation/examples only give it for the SRAM (casually as 0x22000000).Please can someone tell me the address and where it is documented?

[lanchon]

Posted on May 17, 2011 at 12:43

check PERIPH_BB_BASE (and PERIPH_BASE) in the fwlib header files and see the macros here for context:

http://www.st.com/mcu/forums-cat-6567-23.html

[bob239955]

Posted on May 17, 2011 at 12:43

Thankyou Lanchon.

http://www.arm.com/support/faqdev/15921.html

answers my question perfectly. #define BITBAND_SRAM_REF 0x20000000 #define BITBAND_SRAM_BASE 0x22000000 #define BITBAND_SRAM(addr,bit) ((BITBAND_SRAM_BASE + (addr-BITBAND_SRAM_REF)*32 + (bit*4))) #define BITBAND_PERI_REF 0x40000000 #define BITBAND_PERI_BASE 0x42000000 #define BITBAND_PERI(addr,bit) ((BITBAND_PERI_BASE + (addr-BITBAND_PERI_REF)*32 + (bit*4))) I expected to see the alias areas at 0x22000000 and 0x42000000 in the ST datasheet memory maps. Actually this address information is in the

http://infocenter.arm.com/help/topic/com.arm.doc.ddi0337g/DDI0337G_cortex_m3_r2p0_trm.pdf

Section 4.1 About the Memory Map.[ This message was edited by: bobz on 07-09-2008 23:50 ]

[lanchon]

Posted on May 17, 2011 at 12:43

as a matter of taste, I prefer to use these macros

#include ''stm32f10x_lib.h'' #define BB_BIT(REGISTER, BIT_NUMBER, BASE, BB_BASE) ((volatile s32*) ((BB_BASE) + (((u32) &(REGISTER)) - (BASE)) * 32 + (BIT_NUMBER) * 4)) #define PERIPHERAL_BIT(REGISTER, BIT_NUMBER) BB_BIT(REGISTER, BIT_NUMBER, PERIPH_BASE, PERIPH_BB_BASE) #define SRAM_BIT(REGISTER, BIT_NUMBER) BB_BIT(REGISTER, BIT_NUMBER, SRAM_BASE, SRAM_BB_BASE) #define MY_LED PERIPHERAL_BIT(GPIOC->ODR, 12) // *MY_LED = 1;