Datasheet

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STM32F427xx STM32F429xx Functional overview
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3.11 Chrom-ART Accelerator™ (DMA2D)
The Chrom-Art Accelerator™ (DMA2D) is a graphic accelerator which offers advanced bit
blitting, row data copy and pixel format conversion. It supports the following functions:
• Rectangle filling with a fixed color
• Rectangle copy
• Rectangle copy with pixel format conversion
• Rectangle composition with blending and pixel format conversion.
Various image format coding are supported, from indirect 4bpp color mode up to 32bpp
direct color. It embeds dedicated memory to store color lookup tables.
An interrupt can be generated when an operation is complete or at a programmed
watermark.
All the operations are fully automatized and are running independently from the CPU or the
DMAs.
3.12 Nested vectored interrupt controller (NVIC)
The devices embed a nested vectored interrupt controller able to manage 16 priority levels,
and handle up to 91 maskable interrupt channels plus the 16 interrupt lines of the Cortex
®
-
M4 with FPU core.
• Closely coupled NVIC gives low-latency interrupt processing
• Interrupt entry vector table address passed directly to the core
• Allows early processing of interrupts
• Processing of late arriving, higher-priority interrupts
• Support tail chaining
• Processor state automatically saved
• Interrupt entry restored on interrupt exit with no instruction overhead
This hardware block provides flexible interrupt management features with minimum interrupt
latency.
3.13 External interrupt/event controller (EXTI)
The external interrupt/event controller consists of 23 edge-detector lines used to generate
interrupt/event requests. Each line can be independently configured to select the trigger
event (rising edge, falling edge, both) and can be masked independently. A pending register
maintains the status of the interrupt requests. The EXTI can detect an external line with a
pulse width shorter than the Internal APB2 clock period. Up to 168 GPIOs can be connected
to the 16 external interrupt lines.
3.14 Clocks and startup
On reset the 16 MHz internal RC oscillator is selected as the default CPU clock. The
16 MHz internal RC oscillator is factory-trimmed to offer 1% accuracy over the full
temperature range. The application can then select as system clock either the RC oscillator
or an external 4-26 MHz clock source. This clock can be monitored for failure. If a failure is
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