For STM32L4, hardware I2C can be implemented by using TIMINGR.
This commit enables:
- Use of hardware I2C in machine.I2C.
- Specifying a frequency greater than or equal to 400KHz with pyb.I2C.
Excuting the code:
i2c = I2C(1, I2C.CONTROLLER, dma=True)
tmp = i2c.recv(1, i2c_addr)
recv_data = bytearray(56)
i2c.recv(recv_data, i2c_addr)
The second i2c.recv() fails with OSError: [Errno 110] ETIMEDOUT. When
receiving greater than or equal to 2 bytes at first i2c.recv(), the second
i2c.recv() succeeds. This issue does not occur without DMA.
Details of change: when executing I2C with DMA:
- Bit 11 of I2Cx_CR2 (DMA Request Enable) should be 1 to indicate that DMA
transfer is enabled. This bit is set after I2C event interrupt is
enabled in HAL_I2C_Master_Transmit_DMA()/HAL_I2C_Master_Receive_DMA(), so
DMA Request Enable bit might be 0 in IRQHandler.
- In case of data receive:
- When only 1 byte receiption, clear I2Cx_CR1's bit 10 (ACK).
- When only 2 byte receiption, clear I2Cx_CR1's bit 10 (ACK) and set
bit 11 (POS).
- When greater than or equal to 2 byte receiption, bit 12 of I2Cx_CR2
(DMA Last Transfer) should set to generate NACK when DMA transfer
completed.
Otherwise, the I2C bus may be busy after received data from peripheral.
Instead of being an explicit field, it's now a slot like all the other
methods.
This is a marginal code size improvement because most types have a make_new
(100/138 on PYBV11), however it improves consistency in how types are
declared, removing the special case for make_new.
Signed-off-by: Jim Mussared <jim.mussared@gmail.com>
Prior to this commit, excuting this code:
i2c = I2C(1, I2C.CONTROLLER, dma=True)
i2c.send(data, addr=i2c_addr)
the call to i2c.send() does not return and the board needs a reset. This
code works when dma=False.
According to the specification, I2Cx_EV_IRQHandler should:
- Write DR to address when Start condition generated.
- Clear ADDR by reading SR2 after reading SR2 when address sent.
These processes are included in HAL_I2C_EV_IRQHandler(), however the
firmware size increses about 2KB if HAL_I2C_EV_IRQHandler is called. This
commit adds above processes to i2c_ev_irq_handler, and increases firmware
by less than 100 bytes.
Fixes issue #2643.
Previously the desired output type was specified. Now make the type part
of the function name. Because this function is used in a few places this
saves code size due to smaller call-site.
This makes `mp_obj_new_str_type_from_vstr` a private function of objstr.c
(which is almost the only place where the output type isn't a compile-time
constant).
This saves ~140 bytes on PYBV11.
Signed-off-by: Jim Mussared <jim.mussared@gmail.com>
This commit adds support for the STM32G4 series of MCUs, and a board
definition for NUCLEO_G474RE. This board has the REPL on LPUART1 which is
connected to the on-board ST-link USB-UART.
Replace "master" with "controller" and "slave" with "peripheral" in
comments, errors, and debug messages.
Add CONTROLLER and PERIPHERAL constants to pyb.SPI and pyb.I2C classes;
retain MASTER and SLAVE constants for backward compatiblity.
Now that error string compression is supported it's more important to have
consistent error string formatting (eg all lowercase English words,
consistent contractions). This commit cleans up some of the strings to
make them more consistent.
On MCUs that have an I2C TIMINGR register, this can now be explicitly set
via the "timingr" keyword argument to the I2C constructor, for both
machine.I2C and pyb.I2C. This allows to configure precise timing values
when the defaults are inadequate.
This part is functionally similar to STM32F767xx (they share a datasheet)
so support is generally comparable. When adding board support the
stm32f767_af.csv and stm32f767.ld should be used.
With this and previous patches the stm32 port can now be compiled using
object representation D (nan boxing). Note that native code and frozen mpy
files with float constants are currently not supported with this object
representation.
When disabled, the pyb.I2C class saves around 8k of code space and 172
bytes of RAM. The same functionality is now available in machine.I2C
(for F4 and F7 MCUs).
It is still enabled by default.
On this 32-bit arch there's no need to use the long version of the format
specifier. It's only there to appease the compiler which checks the type
of the args passed to printf. Removing the "l" saves a bit of code space.
Damien George