Hi Alan,
Thank you for the information!
---
My understanding for now is below. (For nucleo-F767 board)
- An initialization file is lying in
nuttx/boards/arm/stm32f7/nucleo-144/src/stm32_appinitialize.c. (Contents
in this file is executed when launching NuttX.)
- Initialization code for specific I2C sensor like MPU9250 should be
called in the file to associate I2C lower-half and specific sensor's
upper-half then register the associated driver as like /dev/mpu.
What I'm not sure is if I always need to use
i2c_drivers.c(i2c_register()) which is in nuttx/drivers/i2c/.
I guess that I don't need to do that. What I need to do is choose which
upper-half driver to use this time. i2c_drivers.c is maybe a general I2C
upper-half driver. That's why it can be used when I just want to
read/write for specific register.
I guess that a driver called I2C upper-half is basecally created not for
communicate to general I2C device but created for a specific I2C device
such as MPU9250 and it provides some data with the form which can be
used directly like gyro, accel, temp... not like gx_h, gx_l, gy_h, gy_l,....
Yuta Ide
On 2021/05/01 21:10, Alan Carvalho de Assis wrote:
Hi Yuta,
stm32_mpu9250initialize("/dev/mpu0");
This function receive the name of the device file it will creste. The
/dev/i2cX is created by the funcion i2c_register().
BR,
Alan
On Saturday, May 1, 2021, yuta <yutr...@gmail.com> wrote:
Gregory,
Thank you for your answer.
I think I'm asking very easy question since I'm very new to NuttX.
I'm not still sure how I can enable an I2C device.
I understood that there are lower-half driver and upper-half driver and
they should be associated each other with initialization code.
Refering some documents like below, I added some lines to do that.
I can see /dev/i2c1 now but i2c tool still does not detect any i2c device.
https://github.com/apache/incubator-nuttx/blob/master/boards
/arm/stm32f0l0g0/nucleo-g070rb/src/stm32_bringup.c#L89-L111
I also tried to make upper-half driver refering here.
https://github.com/micro-ROS/NuttX/issues/9
In this case, I call mpu9250_register() which I made instead of
i2c_register().
/dev/i2c1 appeared with ls /dev.
However, `i2c dev -b 1 0x03 0x77 ` did not detect any i2c device.
Yuta Ide
On 2021/04/30 22:18, Gregory Nutt wrote:
On 4/30/2021 6:34 AM, yuta wrote:
Hi all,
I'm trying to use I2C.
I configured below in menuconfig.
- System Type > STM32 Peripheral Support > [*] I2C1
- Device Drivers > [*] I2C Driver Support
then compilation was done successfully.
But no I2C device( like /dev/i2c1 ) showed up when I tried ls /dev
Do I forget something to do?
I'm using Nucleo-F767ZI board.
Thank you.
Yuta Ide
Did you enable an I2C device? STM32 I2C peripheral support is not an
I2C device. It an I2C "lower half" and will not create a character
device. You also have to (1) enable an "upper half" device that uses I2C,
(2) create an instance of the I2C "lower half", and (3) bind the "lower
half" to the "upper half" and register the driver.
Remember, I2C is not a device. I2C is a bus that provides the physical
transport to devices on the bus. You should not normally do direct bus
access from applications .. although you can with
drivers/i2c/i2c_driver.c. i2c_driver.c can be used by your
board-initialization logic to create a character device that will allow
appliations to access the bus directly. So you can create some kind of
very limited user-space driver. It is limited because it cannot integrate
simply with other aspects of the device such as GPIO controls or interrupts.
