STM32 CCM Example 한국어 번역

Part 1

요약·해설

CCM chosen node, 전체 DTS 예제와 power-on/reset 출력을 설명합니다.

Memory

Core Coupled Memory

Sections

data · bss · noinit

DMA

Not available

Part 2

접을 수 있는 영어 원문 전체

영어 원문 전체 펼치기

원문 SHA-256 4C43FAA9D0662D53AEF4A476FA76F45A484F1CE3FCF04F4627FCFF0C94945F56

.. _samples_boards_stm32_ccm:

STM32 CCM example
#################

Overview
********

Show usage of the Core Coupled Memory (CCM) that is available
on several STM32 devices. The very important difference with
normal RAM is that CCM can not be used for DMA.

By prefixing a variable with __ccm_data_section, __ccm_bss_section,
or __ccm_noinit_section those variables are placed in the CCM.

The __ccm_data_section prefix should be used for variables that
are initialized. Like the normal data section the initial
values take up space in the FLASH image.

The __ccm_bss_section prefix should be used for variables that
should be initialized to 0. Like the normal bss section they
do not take up FLASH space.

The __ccm_noinit_section prefix should be used for variables
that don't need to have a defined initial value (for example
buffers that will receive data). Compared to bss or data the
kernel does not need to initialize the noinit section making
the startup slightly faster.

To add CCM support to a board, add the following line to the
board's DTS file ``chosen`` section:

.. code-block:: console

   zephyr,ccm = &ccm0;

For example the olimex STM32 E407 DTS file looks like this:

.. literalinclude:: ../../../../../../../boards/olimex/stm32_e407/olimex_stm32_e407.dts
   :linenos:

Building and Running
********************

.. zephyr-app-commands::
   :app: samples/boards/stm32/ccm
   :goals: build flash

The first time the example is run after power on, the output will
look like this:

.. code-block:: console

   ***** BOOTING ZEPHYR OS v1.10.99 - BUILD: Jan 14 2018 09:32:46 *****

   CCM (Core Coupled Memory) usage example

   The total used CCM area   : [0x10000000, 0x10000021)
   Zero initialized BSS area : [0x10000000, 0x10000007)
   Uninitialized NOINIT area : [0x10000008, 0x10000013)
   Initialised DATA area     : [0x10000014, 0x10000021)
   Start of DATA in FLASH    : 0x08003940

   Checking initial variable values: ... PASSED

   Initial variable values:
   ccm_data_var_8  addr: 0x10000014 value: 0x12
   ccm_data_var_16 addr: 0x10000016 value: 0x3456
   ccm_data_var_32 addr: 0x10000018 value: 0x789abcde
   ccm_data_array  addr: 0x1000001c size: 5 value:
           0x11 0x22 0x33 0x44 0x55
   ccm_bss_array addr: 0x10000000 size: 7 value:
           0x00 0x00 0x00 0x00 0x00 0x00 0x00
   ccm_noinit_array addr: 0x10000008 size: 11 value:
           0xa9 0x99 0xba 0x90 0xe1 0x2a 0xba 0x93 0x4c 0xfe 0x4b

   Variable values after writing:
   ccm_data_var_8  addr: 0x10000014 value: 0xed
   ccm_data_var_16 addr: 0x10000016 value: 0xcba9
   ccm_data_var_32 addr: 0x10000018 value: 0x87654321
   ccm_data_array  addr: 0x1000001c size: 5 value:
           0xaa 0xaa 0xaa 0xaa 0xaa
   ccm_bss_array addr: 0x10000000 size: 7 value:
           0xbb 0xbb 0xbb 0xbb 0xbb 0xbb 0xbb
   ccm_noinit_array addr: 0x10000008 size: 11 value:
           0xcc 0xcc 0xcc 0xcc 0xcc 0xcc 0xcc 0xcc 0xcc 0xcc 0xcc

   Example end


First, each CCM section is listed with its address and size. Next, some usage
examples are shown. Note that the ``noinit`` section holds variables with
uninitialized data. After writing to the variables, they all should hold the
values shown above.

When the board is reset (without power-cycling), the output looks like this:

.. code-block:: console

   ***** BOOTING ZEPHYR OS v1.10.99 - BUILD: Jan 14 2018 09:32:46 *****

   CCM (Core Coupled Memory) usage example

   The total used CCM area   : [0x10000000, 0x10000021)
   Zero initialized BSS area : [0x10000000, 0x10000007)
   Uninitialized NOINIT area : [0x10000008, 0x10000013)
   Initialised DATA area     : [0x10000014, 0x10000021)
   Start of DATA in FLASH    : 0x08003940

   Checking initial variable values: ... PASSED

   Initial variable values:
   ccm_data_var_8  addr: 0x10000014 value: 0x12
   ccm_data_var_16 addr: 0x10000016 value: 0x3456
   ccm_data_var_32 addr: 0x10000018 value: 0x789abcde
   ccm_data_array  addr: 0x1000001c size: 5 value:
           0x11 0x22 0x33 0x44 0x55
   ccm_bss_array addr: 0x10000000 size: 7 value:
           0x00 0x00 0x00 0x00 0x00 0x00 0x00
   ccm_noinit_array addr: 0x10000008 size: 11 value:
           0xcc 0xcc 0xcc 0xcc 0xcc 0xcc 0xcc 0xcc 0xcc 0xcc 0xcc

   Variable values after writing:
   ccm_data_var_8  addr: 0x10000014 value: 0xed
   ccm_data_var_16 addr: 0x10000016 value: 0xcba9
   ccm_data_var_32 addr: 0x10000018 value: 0x87654321
   ccm_data_array  addr: 0x1000001c size: 5 value:
           0xaa 0xaa 0xaa 0xaa 0xaa
   ccm_bss_array addr: 0x10000000 size: 7 value:
           0xbb 0xbb 0xbb 0xbb 0xbb 0xbb 0xbb
   ccm_noinit_array addr: 0x10000008 size: 11 value:
           0xcc 0xcc 0xcc 0xcc 0xcc 0xcc 0xcc 0xcc 0xcc 0xcc 0xcc

   Example end


The difference with the first run is that the ccm_noinit section still has the
values from the last write. It is important to notice that this is not guaranteed,
it still should be considered uninitialized leftover data.

Part 3

한국어 전문 번역

개요

여러 STM32 device에서 제공하는 Core Coupled Memory(CCM)의 사용법을 보여줍니다. 일반 RAM과의 매우 중요한 차이는 CCM을 DMA에 사용할 수 없다는 점입니다.

Variable 앞에 __ccm_data_section, __ccm_bss_section, __ccm_noinit_section을 붙이면 해당 variable이 CCM에 배치됩니다.

__ccm_data_section은 초기값이 있는 variable에 사용합니다. 일반 data section과 마찬가지로 초기값이 FLASH image의 공간을 차지합니다.

__ccm_bss_section은 0으로 초기화해야 하는 variable에 사용합니다. 일반 bss section처럼 FLASH 공간을 차지하지 않습니다.

__ccm_noinit_section은 data를 수신할 buffer처럼 정의된 초기값이 필요하지 않은 variable에 사용합니다. Kernel이 noinit section을 초기화하지 않아도 되므로 bss나 data보다 startup이 조금 빨라집니다.

Board에 CCM 지원을 추가하려면 board DTS file의 chosen section에 다음 줄을 추가합니다.

zephyr,ccm = &ccm0;

예를 들어 Olimex STM32 E407 DTS file은 다음과 같습니다.

1/*
  2 * Copyright (c) 2017, Erwin Rol <[email protected]>
  3 *
  4 * SPDX-License-Identifier: Apache-2.0
  5 */
  6
  7/dts-v1/;
  8#include <st/f4/stm32f407Xg.dtsi>
  9#include <st/f4/stm32f407z(e-g)tx-pinctrl.dtsi>
 10#include <zephyr/dt-bindings/input/input-event-codes.h>
 11
 12/ {
 13	model = "Olimex STM32-E407 board";
 14	compatible = "olimex,stm32-e407";
 15
 16	chosen {
 17		zephyr,console = &usart1;
 18		zephyr,shell-uart = &usart1;
 19		zephyr,sram = &sram0;
 20		zephyr,flash = &flash0;
 21		zephyr,ccm = &ccm0;
 22	};
 23
 24	leds {
 25		compatible = "gpio-leds";
 26		green_led_1: led_1 {
 27			gpios = <&gpioc 13 GPIO_ACTIVE_HIGH>;
 28			label = "LED1";
 29		};
 30	};
 31
 32	gpio_keys {
 33		compatible = "gpio-keys";
 34		user_button: button {
 35			label = "Key";
 36			gpios = <&gpioa 0 GPIO_ACTIVE_LOW>;
 37			zephyr,code = <INPUT_KEY_0>;
 38		};
 39	};
 40
 41	aliases {
 42		led0 = &green_led_1;
 43		sw0 = &user_button;
 44	};
 45};
 46
 47&clk_lsi {
 48	status = "okay";
 49};
 50
 51&clk_hse {
 52	clock-frequency = <DT_FREQ_M(12)>;
 53	status = "okay";
 54};
 55
 56&pll {
 57	div-m = <12>;
 58	mul-n = <336>;
 59	div-p = <2>;
 60	div-q = <7>;
 61	clocks = <&clk_hse>;
 62	status = "okay";
 63};
 64
 65&rcc {
 66	clocks = <&pll>;
 67	clock-frequency = <DT_FREQ_M(168)>;
 68	ahb-prescaler = <1>;
 69	apb1-prescaler = <4>;
 70	apb2-prescaler = <2>;
 71};
 72
 73&usart1 {
 74	pinctrl-0 = <&usart1_tx_pb6 &usart1_rx_pb7>;
 75	pinctrl-names = "default";
 76	current-speed = <115200>;
 77	status = "okay";
 78};
 79
 80&usart3 {
 81	pinctrl-0 = <&usart3_tx_pb10 &usart3_rx_pb11>;
 82	pinctrl-names = "default";
 83	current-speed = <115200>;
 84	status = "okay";
 85};
 86
 87&usart6 {
 88	pinctrl-0 = <&usart6_tx_pc6 &usart6_rx_pc7>;
 89	pinctrl-names = "default";
 90	current-speed = <115200>;
 91	status = "okay";
 92};
 93
 94&rtc {
 95	clocks = <&rcc STM32_CLOCK_BUS_APB1 0x10000000>,
 96		 <&rcc STM32_SRC_LSI RTC_SEL(2)>;
 97	status = "okay";
 98};
 99
100&rng {
101	status = "okay";
102};
103
104/* Only one interface should be enabled at a time: usbotg_fs or usbotg_hs */
105usb_otg1: &usbotg_fs {
106	pinctrl-0 = <&usb_otg_fs_dm_pa11 &usb_otg_fs_dp_pa12>;
107	pinctrl-names = "default";
108	status = "disabled";
109};
110
111zephyr_udc0: &usbotg_hs {
112	pinctrl-0 = <&usb_otg_hs_dm_pb14 &usb_otg_hs_dp_pb15>;
113	pinctrl-names = "default";
114	status = "okay";
115};
116
117&mac {
118	status = "okay";
119	pinctrl-0 = <&eth_mdc_pc1
120		     &eth_rxd0_pc4
121		     &eth_rxd1_pc5
122		     &eth_ref_clk_pa1
123		     &eth_mdio_pa2
124		     &eth_col_pa3
125		     &eth_crs_dv_pa7
126		     &eth_tx_en_pg11
127		     &eth_txd0_pg13
128		     &eth_txd1_pg14>;
129	pinctrl-names = "default";
130};

Build와 실행

west build -b None samples/boards/stm32/ccm
west flash

Power-on 뒤 예제를 처음 실행하면 다음과 같은 출력이 나타납니다.

***** BOOTING ZEPHYR OS v1.10.99 - BUILD: Jan 14 2018 09:32:46 *****

CCM (Core Coupled Memory) usage example

The total used CCM area   : [0x10000000, 0x10000021)
Zero initialized BSS area : [0x10000000, 0x10000007)
Uninitialized NOINIT area : [0x10000008, 0x10000013)
Initialised DATA area     : [0x10000014, 0x10000021)
Start of DATA in FLASH    : 0x08003940

Checking initial variable values: ... PASSED

Initial variable values:
ccm_data_var_8  addr: 0x10000014 value: 0x12
ccm_data_var_16 addr: 0x10000016 value: 0x3456
ccm_data_var_32 addr: 0x10000018 value: 0x789abcde
ccm_data_array  addr: 0x1000001c size: 5 value:
        0x11 0x22 0x33 0x44 0x55
ccm_bss_array addr: 0x10000000 size: 7 value:
        0x00 0x00 0x00 0x00 0x00 0x00 0x00
ccm_noinit_array addr: 0x10000008 size: 11 value:
        0xa9 0x99 0xba 0x90 0xe1 0x2a 0xba 0x93 0x4c 0xfe 0x4b

Variable values after writing:
ccm_data_var_8  addr: 0x10000014 value: 0xed
ccm_data_var_16 addr: 0x10000016 value: 0xcba9
ccm_data_var_32 addr: 0x10000018 value: 0x87654321
ccm_data_array  addr: 0x1000001c size: 5 value:
        0xaa 0xaa 0xaa 0xaa 0xaa
ccm_bss_array addr: 0x10000000 size: 7 value:
        0xbb 0xbb 0xbb 0xbb 0xbb 0xbb 0xbb
ccm_noinit_array addr: 0x10000008 size: 11 value:
        0xcc 0xcc 0xcc 0xcc 0xcc 0xcc 0xcc 0xcc 0xcc 0xcc 0xcc

Example end

먼저 각 CCM section과 그 address·size를 나열하고, 이어서 사용 예를 보여줍니다. noinit section은 초기화되지 않은 data를 가진 variable을 보관합니다. Variable에 값을 쓴 뒤에는 모두 위에 표시된 값을 가져야 합니다.

Board의 전원을 끄지 않고 reset하면 출력은 다음과 같습니다.

***** BOOTING ZEPHYR OS v1.10.99 - BUILD: Jan 14 2018 09:32:46 *****

CCM (Core Coupled Memory) usage example

The total used CCM area   : [0x10000000, 0x10000021)
Zero initialized BSS area : [0x10000000, 0x10000007)
Uninitialized NOINIT area : [0x10000008, 0x10000013)
Initialised DATA area     : [0x10000014, 0x10000021)
Start of DATA in FLASH    : 0x08003940

Checking initial variable values: ... PASSED

Initial variable values:
ccm_data_var_8  addr: 0x10000014 value: 0x12
ccm_data_var_16 addr: 0x10000016 value: 0x3456
ccm_data_var_32 addr: 0x10000018 value: 0x789abcde
ccm_data_array  addr: 0x1000001c size: 5 value:
        0x11 0x22 0x33 0x44 0x55
ccm_bss_array addr: 0x10000000 size: 7 value:
        0x00 0x00 0x00 0x00 0x00 0x00 0x00
ccm_noinit_array addr: 0x10000008 size: 11 value:
        0xcc 0xcc 0xcc 0xcc 0xcc 0xcc 0xcc 0xcc 0xcc 0xcc 0xcc

Variable values after writing:
ccm_data_var_8  addr: 0x10000014 value: 0xed
ccm_data_var_16 addr: 0x10000016 value: 0xcba9
ccm_data_var_32 addr: 0x10000018 value: 0x87654321
ccm_data_array  addr: 0x1000001c size: 5 value:
        0xaa 0xaa 0xaa 0xaa 0xaa
ccm_bss_array addr: 0x10000000 size: 7 value:
        0xbb 0xbb 0xbb 0xbb 0xbb 0xbb 0xbb
ccm_noinit_array addr: 0x10000008 size: 11 value:
        0xcc 0xcc 0xcc 0xcc 0xcc 0xcc 0xcc 0xcc 0xcc 0xcc 0xcc

Example end

첫 실행과 다른 점은 ccm_noinit section이 마지막 write의 값을 계속 보관한다는 것입니다. 그러나 이는 보장된 동작이 아니며, 이 data는 여전히 초기화되지 않은 leftover data로 취급해야 합니다.

Source

출처

영어 원문에는 문단, 문서 지시문, 표, 코드, 코드 심벌, 경로를 그대로 보존했습니다.

STM32 CCM Example

2.7.0 LTS2 · 준비 중

요약·해설

접을 수 있는 영어 원문 전체

한국어 전문 번역

개요

Build와 실행

출처