This reduces the popping sound on initial playback of an audio
sample.
The M4 DAC has a pop on startup that cannot be prevented. It also
does not allow readback so current values of the DAC are ignored.
Fixes#1090
Also, renamed Sprite's palette to pixel_shader so it can be
anything that produces colors based on values (including color values).
Added a ColorConverter that converts RGB888 (found in bitmaps) to
RGB565 for the display.
Fixes#1182
It's designed to minimize RAM footprint by using Sprites to
represent objects on the screen. The object model also facilitates
partial screen updating which reduces the bandwidth needed to display.
This is all handled in C. Python simply manipulates the objects with
the ability to synchronize to frame timing.
Commit 95e70cd0ea6d 'time: Use 1970 epoch' changed epoch for the time
module, but not for other users. This patch does the same for the only
other core timeutils user: extmod/vfs_fat.c:fat_vfs_stat().
Other timeutils users: cc3200, esp8266 and stm32, are not changed.
Ports that don't use long ints, will still get wrong time values from
os.stat().
This saves code space in builds which use link-time optimization.
The optimization drops the untranslated strings and replaces them
with a compressed_string_t struct. It can then be decompressed to
a c string.
Builds without LTO work as well but include both untranslated
strings and compressed strings.
This work could be expanded to include QSTRs and loaded strings if
a compress method is added to C. Its tracked in #531.
Particularly when they have buffers that are written via IRQ or DMA,
UART objects do not relocate gracefully. If such an object is
relocated to the long-lived pool after its original creation, the
IRQ or DMA will write to an unexpected location within the Python
heap, leading to a variety of symptoms. The most frequent symptom
is inability to read from the UART.
Consider the particular case of atmel-samd: usart_uart_obj_t
contains a usart_async_descriptor contains a _usart_async_device.
In _sercom_init_irq_param the address of this contained
_usart_async_device is assigned to a global array
sercom_to_sercom_dev which is later used from the interrupt context
_sercom_usart_interrupt_handler to store the received data in the
right ring buffer.
When the UART object is relocated to the long-lived heap, there's no
mechanism to re-point these internal pointers, so instead take the
cowardly way and allocate the UART object as long-lived.
Happily, almost all UART objects are likely to be long-lived, so
this is unlikely to have a negative effect on memory usage or heap
fragmentation.
Closes: #1056
Its slimmed down by removing the qstr and bit packing TCC info.
The trinket m0 build actually grows by 20 bytes. The arduino zero
build shrinks by 188 bytes.
