circuitpython/ports/stm32/dac.h
Damien George aa7b32c811 stm32/dac: Rework DAC driver to use direct register access.
This patch makes the DAC driver simpler and removes the need for the ST
HAL.  As part of it, new helper functions are added to the DMA driver,
which also use direct register access instead of the ST HAL.

Main changes to the DAC interface are:

- The DAC uPy object is no longer allocated dynamically on the heap,
  rather it's statically allocated and the same object is retrieved for
  subsequent uses of pyb.DAC(<id>).  This allows to access the DAC objects
  without resetting the DAC peripheral.  It also means that the DAC is only
  reset if explicitly passed initialisation parameters, like "bits" or
  "buffering".

- The DAC.noise() and DAC.triangle() methods now output a signal which is
  full scale (previously it was a fraction of the full output voltage).

- The DAC.write_timed() method is fixed so that it continues in the
  background when another peripheral (eg SPI) uses the DMA (previously the
  DAC would stop if another peripheral finished with the DMA and shut the
  DMA peripheral off completely).

Based on the above, the following backwards incompatibilities are
introduced:

- pyb.DAC(id) will now only reset the DAC the first time it is called,
  whereas previously each call to create a DAC object would reset the DAC.
  To get the old behaviour pass the bits parameter like: pyb.DAC(id, bits).

- DAC.noise() and DAC.triangle() are now full scale.  To get previous
  behaviour (to change the amplitude and offset) write to the DAC_CR (MAMP
  bits) and DAC_DHR12Rx registers manually.
2019-04-24 15:51:19 +10:00

32 lines
1.4 KiB
C

/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2013, 2014 Damien P. George
*
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*/
#ifndef MICROPY_INCLUDED_STM32_DAC_H
#define MICROPY_INCLUDED_STM32_DAC_H
extern const mp_obj_type_t pyb_dac_type;
#endif // MICROPY_INCLUDED_STM32_DAC_H