Reading USB registers directly on a Nordic nRF5340 DK

[BIA_JHLL]

Hi everyone,

We are using the NCS 2.4.2 and the development board nRF5340 DK. We would like to read USB register as shown in the datasheet of this board (Attach this info), specifically REGISTER

And I have coded the following: 

/*
 * Copyright (c) 2018 Phytec Messtechnik GmbH
 *
 * SPDX-License-Identifier: Apache-2.0
 */


#include <logging/log.h>
#include <stdint.h>

LOG_MODULE_REGISTER(main);

// Define the USB peripheral base address
#define USB_BASE_ADDR 0x50037000

// Define USB register offsets
#define EVENTS_USBDETECTED_OFFSET 0x100

void main(void)
{
        volatile uint32_t *usb_base = (uint32_t *)USB_BASE_ADDR;

        // Read USB control register.
        uint32_t event_usb_detected = usb_base[EVENTS_USBDETECTED_OFFSET];

        if(event_usb_detected == 1){
          LOG_INF("USB EVENT detected");

        }

        // Do something with the register values.

        
}

With this error, titled as "missing expression":

C:\ncs\v1.7.0\toolchain\opt/bin/arm-none-eabi-gcc -DBUILD_VERSION=v2.6.99-ncs1 
-DEXT_API_MAGIC=0x281ee6de,0xb845acea,13570 -DFIRMWARE_INFO_MAGIC=0x281ee6de,0x8fcebb4c,13570 -DKERNEL 
-DNRF5340_XXAA_APPLICATION -DNRF_TRUSTZONE_NONSECURE -DUSE_PARTITION_MANAGER=1 -D_FORTIFY_SOURCE=2 
-D__PROGRAM_START -D__ZEPHYR__=1 -I../../../../../kernel/include -I../../../../../arch/arm/include 
-I../../../../../include -Izephyr/include/generated -I../../../../../soc/arm/nordic_nrf/nrf53 
-IC:/ncs/v1.7.0/nrf/include -IC:/ncs/v1.7.0/modules/hal/cmsis/CMSIS/Core/Include 
-IC:/ncs/v1.7.0/modules/hal/nordic/nrfx -IC:/ncs/v1.7.0/modules/hal/nordic/nrfx/drivers/include 
-IC:/ncs/v1.7.0/modules/hal/nordic/nrfx/mdk -I../../../../../modules/hal_nordic/nrfx/. -isystem 
../../../../../lib/libc/minimal/include -isystem 
c:/ncs/v1.7.0/toolchain/opt/bin/../lib/gcc/arm-none-eabi/9.2.1/include -isystem 
c:/ncs/v1.7.0/toolchain/opt/bin/../lib/gcc/arm-none-eabi/9.2.1/include-fixed -Os -imacros 
C:/ncs/v1.7.0/zephyr/samples/subsys/usb/hid/build_nrf5340dk_nrf5340_cpuapp_ns/zephyr/include/generated/autoconf.h 
-ffreestanding -fno-common -g -gdwarf-4 -fdiagnostics-color=always -mcpu=cortex-m33 -mthumb -mabi=aapcs 
-imacros C:/ncs/v1.7.0/zephyr/include/toolchain/zephyr_stdint.h -Wall -Wformat -Wformat-security 
-Wno-format-zero-length -Wno-main -Wno-pointer-sign -Wpointer-arith -Wexpansion-to-defined 
-Wno-address-of-packed-member -Wno-unused-but-set-variable -Werror=implicit-int -fno-asynchronous-unwind-tables 
-fno-pie -fno-pic -fno-strict-overflow -fno-reorder-functions -fno-defer-pop 
-fmacro-prefix-map=C:/ncs/v1.7.0/zephyr/samples/subsys/usb/hid=CMAKE_SOURCE_DIR 
-fmacro-prefix-map=C:/ncs/v1.7.0/zephyr=ZEPHYR_BASE -fmacro-prefix-map=C:/ncs/v1.7.0=WEST_TOPDIR 
-ffunction-sections -fdata-sections -std=c99 -nostdinc -MD -MF 
C:/ncs/v1.7.0/zephyr/samples/subsys/usb/hid/build_nrf5340dk_nrf5340_cpuapp_ns/zephyr\CMakeFiles\zephyr.dir\misc\generated\configs.c.obj.d 
-fno-diagnostics-show-caret -o zephyr/CMakeFiles/zephyr.dir/misc/generated/configs.c.obj -c zephyr/misc/generated/configs.c

[Øivind]

Hi,

You are building this through VS Code, correct?
Could I see your prj.conf and the full build log?

[BIA_JHLL]

#
# Copyright (c) 2018 Nordic Semiconductor
#
# SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
#
CONFIG_NCS_SAMPLES_DEFAULTS=y

CONFIG_BT=y
CONFIG_BT_PERIPHERAL=y
CONFIG_BT_DEVICE_NAME="Nordic_LBS"

# Enable the LBS service
CONFIG_BT_LBS=y
CONFIG_BT_LBS_POLL_BUTTON=y
CONFIG_DK_LIBRARY=y

CONFIG_SYSTEM_WORKQUEUE_STACK_SIZE=2048

CONFIG_GPIO=y

At this moment, the project compiles properly but all the registers's values give me 0 (cero). I tried with all USBREG registers of the aforementioned picture.

I checked this using debug tool and got the same results.

My objective is to read the USB registers's values.

Thanks in advanced.

[Øivind]

Could you give me an example of a register you would expect to have a non-zero value? Many of these registers are event registers, and would be be read as 1 in the event handler if that event is what caused the handler to be called.

[BIA_JHLL]

This register for example EVENTS_USBDETECTED with a offset=0x100. I don’t know right now if I am reading properly every register, because of you mentioned already, about I need to implement an event handler. And I don’t have any of that in my source code. 

Thanks in advance.

Jhon 

[Øivind]

You can try some of these registers of the peripheral, instead of the regulator.

https://infocenter.nordicsemi.com/index.jsp?topic=%2Fps_nrf5340%2Fchapters%2Fusbd%2Fdoc%2Fusbd.html&cp=4_0_0_6_38_12&anchor=topic

Base address would be 0x50036000 in a secure build. If the USB is enabled, you can for example try to read the ENABLE register with offset 0x500

https://infocenter.nordicsemi.com/index.jsp?topic=%2Fps_nrf5340%2Fchapters%2Fusbd%2Fdoc%2Fusbd.html&cp=4_0_0_6_38_12_60&anchor=register.ENABLE

[BIA_JHLL]

I got an error trying to access in the secure peripheral. I attach the error log from the program TERATERM.

For this reason i tried to access the base address 0x40036000 (Non-secure peripheral) and finally I get a zero value.

Do you have any idea why it is happening?

Thanks in advance.

Jhon

[Øivind]

Ok, so you are building for nrf5340dk_nrf5340_cpuapp_ns?