AT91SAM9G45-EKES Atmel, AT91SAM9G45-EKES Datasheet - Page 277

• Manufacturer Part Number: AT91SAM9G45-EKES
• Description: KIT EVAL FOR AT91SAM9G45
• Manufacturer: Atmel
• Series: AT91SAM Smart ARMr
• Type: MCUr

Specifications of AT91SAM9G45-EKES

• Contents: Board
• Processor To Be Evaluated: SAM9G45
• Data Bus Width: 32 bit
• Interface Type: I2C, SPI, UART
• Maximum Operating Temperature: + 50 C
• Minimum Operating Temperature: - 10 C
• Operating Supply Voltage: 1.8 V to 3.3 V
• For Use With/related Products: AT91SAM9G45
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: Q4626953

23. Peripheral DMA Controller (PDC)
23.1
23.2
6438F–ATARM–21-Jun-10
Description
Embedded Characteristics
The Peripheral DMA Controller (PDC) transfers data between on-chip serial peripherals and the
on- and/or off-chip memories. The link between the PDC and a serial peripheral is operated by
the AHB to ABP bridge.
The user interface of each PDC channel is integrated into the user interface of the peripheral it
serves. The user interface of mono directional channels (receive only or transmit only), contains
two 32-bit memory pointers and two 16-bit counters, one set (pointer, counter) for current trans-
fer and one set (pointer, counter) for next transfer. The bi-directional channel user interface
contains four 32-bit memory pointers and four 16-bit counters. Each set (pointer, counter) is
used by current transmit, next transmit, current receive and next receive.
Using the PDC removes processor overhead by reducing its intervention during the transfer.
This significantly reduces the number of clock cycles required for a data transfer, which
improves microcontroller performance.
To launch a transfer, the peripheral triggers its associated PDC channels by using transmit and
receive signals. When the programmed data is transferred, an end of transfer interrupt is gener-
ated by the peripheral itself.
The Peripheral DMA Controller handles transfer requests from the channel according to the fol-
lowing priorities (Low to High priorities):
Table 23-1.
Instance name
DBGU
USART3
USART2
USART1
USART0
AC97C
SPI1
SPI0
SSC1
SSC0
TSADCC
DBGU
USART3
• Acting as one AHB Bus Matrix Master
• Allows data transfers from/to peripheral to/from any memory space without any intervention
• Next Pointer support, prevents strong real-time constraints on buffer management.
of the processor.
Peripheral DMA Controller
Channel T/R
Transmit
Transmit
Transmit
Transmit
Transmit
Transmit
Transmit
Transmit
Transmit
Transmit
Receive
Receive
Receive
AT91SAM9G45
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