Datasheet

DocID027096 Rev 2 27/137
STM32L073xx Functional overview
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3.10 Direct memory access (DMA)
The flexible 7-channel, general-purpose DMA is able to manage memory-to-memory,
peripheral-to-memory and memory-to-peripheral transfers. The DMA controller supports
circular buffer management, avoiding the generation of interrupts when the controller
reaches the end of the buffer.
Each channel is connected to dedicated hardware DMA requests, with software trigger
support for each channel. Configuration is done by software and transfer sizes between
source and destination are independent.
The DMA can be used with the main peripherals: SPI, I
2
C, USART, LPUART,
general-purpose timers, DAC, and ADC.
3.11 Liquid crystal display (LCD)
The LCD drives up to 8 common terminals and 48 segment terminals to drive up to 384
pixels.
• Internal step-up converter to guarantee functionality and contrast control irrespective of
V
DD
. This converter can be deactivated, in which case the V
LCD
pin is used to provide
the voltage to the LCD
• Supports static, 1/2, 1/3, 1/4 and 1/8 duty
• Supports static, 1/2, 1/3 and 1/4 bias
• Phase inversion to reduce power consumption and EMI
• Up to 8 pixels can be programmed to blink
• Unneeded segments and common pins can be used as general I/O pins
• LCD RAM can be updated at any time owing to a double-buffer
• The LCD controller can operate in Stop mode
• V
LCD
rails decoupling capability
3.12 Analog-to-digital converter (ADC)
A native 12-bit, extended to 16-bit through hardware oversampling, analog-to-digital
converter is embedded into STM32L073xx device. It has up to 16 external channels and 3
internal channels (temperature sensor, voltage reference, V
LCD
voltage measurement). It
performs conversions in single-shot or scan mode. In scan mode, automatic conversion is
performed on a selected group of analog inputs.
The ADC frequency is independent from the CPU frequency, allowing maximum sampling
rate of 1.14 MSPS even with a low CPU speed. The ADC consumption is low at all
frequencies (~25 µA at 10 kSPS, ~240 µA at 1MSPS). An auto-shutdown function
guarantees that the ADC is powered off except during the active conversion phase.
The ADC can be served by the DMA controller. It can operate from a supply voltage down to
1.65 V.
The ADC features a hardware oversampler up to 256 samples, this improves the resolution
to 16 bits (see AN2668).
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