This commit adds support for the `timeout` keyword argument to machine.I2C
on the rp2 port, following how it's done on other ports.
The main motivation here is avoid the interpreter crashing due to infinite
loops when SDA is stuck low, which is quite common if the board gets reset
while reading from an I2C device.
A default timeout of 50ms is chosen because it's consistent with:
- Commit a707fe50b0 which used a timeout of
50,000us for zero-length writes on the rp2 port.
- The machine.SoftI2C class which uses 50,000us as the default timeout.
- The stm32 port's hardware I2C, which uses 50,000us for
I2C_POLL_DEFAULT_TIMEOUT_US.
This commit also fixes the default timeout on the esp32 port to be
consistent with the above, and updates the documentation for machine.I2C to
document this keyword argument.
Each SoC family has its own clocks and timings/timeouts. For I2C, the
default source clock is either APB (ESP32, ESP32-S2) or XTAL (ESP32-S3,
ESP32-C3) as shown in the datasheets. Since
machine_i2c.c/machine_hw_i2c_init() uses the default clk_flags (0), the
alternate low-power clock source is never selected in ESP-IDF
i2c.c/i2c_param_config(). There is not an API in i2c.c to get the source
clock frequency, so a compile-time value is used based on SoC family.
Also, the maximum timeout is different across the SoC families, so use the
I2C_LL_MAX_TIMEOUT constant to eliminate the warning from
i2c_set_timeout().
With these changes, the following results were obtained. The I2C SCL
frequencies were measured with a Saleae logic analyzer.
ESP32 (TTGO T Dislay)
I2C(0, scl=22, sda=21, freq=101781) Measured: 100KHz
I2C(0, scl=22, sda=21, freq=430107) Measured: 400KHz
I2C(0, scl=22, sda=21, freq=1212121) Measured: 941KHz
ESP32-S3 (TTGO T-QT)
I2C(0, scl=34, sda=33, freq=111111) Measured: 107KHz
I2C(0, scl=34, sda=33, freq=444444) Measured: 400KHz
I2C(0, scl=34, sda=33, freq=1111111) Measured: 842KHz
ESP32-C3 (XIAO ESP32C3)
I2C(0, scl=7, sda=6, freq=107816) Measured: 103KHz
I2C(0, scl=7, sda=6, freq=444444) Measured: 380KHz
I2C(0, scl=7, sda=6, freq=1176470) Measured: 800KHz
(ESP32-S2 board was not available for testing.)
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>
When MICROPY_PY_MACHINE_I2C_TRANSFER_WRITE1 is enabled the port's hardware
I2C transfer functions should support the MP_MACHINE_I2C_FLAG_WRITE1
option, but software I2C will not. So add a flag to the I2C protocol
struct so each individual protocol can indicate whether it supports this
option or not.
Fixes issue #8765.
Signed-off-by: Damien George <damien@micropython.org>
I2C transfers are much more efficient if they are combined, instead of
doing separate writes and reads.
Fixes issue #7134.
Signed-off-by: Damien George <damien@micropython.org>
Hardware I2C implementations must provide a .init() protocol method if they
want to support reconfiguration. Otherwise the default is that i2c.init()
raises an OSError (currently the case for all ports).
mp_machine_soft_i2c_locals_dict is renamed to mp_machine_i2c_locals_dict to
match the generic SPI bindings.
Fixes issue #6623 (where calling .init() on a HW I2C would crash).
Signed-off-by: Damien George <damien@micropython.org>
With a warning that this way of constructing software I2C/SPI is
deprecated. The check and warning will be removed in a future release.
This should help existing code to migrate to the new SoftI2C/SoftSPI types.
Signed-off-by: Damien George <damien@micropython.org>
Previous commits removed the ability for one I2C/SPI constructor to
construct both software- or hardware-based peripheral instances. Such
construction is now split to explicit soft and non-soft types.
This commit makes both types available in all ports that previously could
create both software and hardware peripherals: machine.I2C and machine.SPI
construct hardware instances, while machine.SoftI2C and machine.SoftSPI
create software instances.
This is a breaking change for use of software-based I2C and SPI. Code that
constructed I2C/SPI peripherals in the following way will need to be
changed:
machine.I2C(-1, ...) -> machine.SoftI2C(...)
machine.I2C(scl=scl, sda=sda) -> machine.SoftI2C(scl=scl, sda=sda)
machine.SPI(-1, ...) -> machine.SoftSPI(...)
machine.SPI(sck=sck, mosi=mosi, miso=miso)
-> machine.SoftSPI(sck=sck, mosi=mosi, miso=miso)
Code which uses machine.I2C and machine.SPI classes to access hardware
peripherals does not need to change.
Signed-off-by: Damien George <damien@micropython.org>
