thingkillo.blogg.se - Epd partial update for stm32 driver

EPD PARTIAL UPDATE FOR STM32 DRIVER SERIAL
EPD PARTIAL UPDATE FOR STM32 DRIVER 32 BIT
EPD PARTIAL UPDATE FOR STM32 DRIVER SOFTWARE

In P2M mode, the inverse of the above is true.Sean suspects that only the request triggers are channel dependent, and that any valid address on the bus may be chosen as the destination address.

The destination address must be a peripheral address on the AHB bus, though, the documentation is not clear on whether this address must be the specific peripheral of the selected channel, or any valid address in the AHB bus. In M2P mode, the source address could be an SRAM address, flash address, or any other address the DMA port may be connected to in the MCU’s bus matrix.The source data size and destination data size are independently configurable.Įach stream has a source and a destination address pointer. The stream can access data as either a char, half-word, or word (int_8, int_16, or int_32).

EPD PARTIAL UPDATE FOR STM32 DRIVER SOFTWARE

The channels are OR’d with a software trigger that can manually invoke the DMA transfer process.

EPD PARTIAL UPDATE FOR STM32 DRIVER SERIAL

In example, a request may be initiated upon arrival of new data to a serial port peripheral. The channel selects a DMA trigger (“request”), which can be used to start the DMA transfer process based on a peripheral’s state and configuration. This is useful as it allows the standard bus matrix to be bypassed and latency to be significantly reduced.Įach stream has 8 “channels”, which can be thought of as a multiplexer for the peripheral bus. The DMA controllers have access to a special bus (“AHB peripheral port”) which gives them rapid-access to selected peripherals. In example, Stream 0 has higher priority than Stream 1.

Interrupt flags for half-transfer, transfer-complete, error…Įach stream’s priority can be set in software, but if two streams have equal software priority, the one with the higher hardware priority gets favored.

EPD PARTIAL UPDATE FOR STM32 DRIVER 32 BIT

4 x 32 bit FIFO which can be enabled or disabled.

Memory address incrementation on source and destination addresses.

The DMA controller can operate in the following ways:Įach controller has 8 “streams”, which independently support

This means DMA2 is also capable of memory-to-memory transfers (unlike DMA1), as it has two connections to the bus matrix. The DMA2 controller has three ports: two memory ports that can access system memory, and a peripheral port which can access the peripheral bus. It is faster to use this controller when talking to peripherals, as it has a direct connection to the peripherals which bypasses the bus matrix. Thus, it has only one connection to the bus matrix. The DMA1 controller has two ports: a memory port that can access system memory, and a peripheral port which can access the peripheral bus. Streams are pathways where memory can flow, and each processor has 8 to work with. The STM32 microcontroller family has 2 DMA controllers, and 16 DMA “streams”. STMicro’s documentation about the subject is some of the most terse documentation I’ve ever seen in the business! This cheat sheet is a work-in-progress.