AT91SAM7X128 Atmel, AT91SAM7X128 Datasheet - Page 141

• Manufacturer Part Number: AT91SAM7X128
• Description: MCU 32-Bit 91S ARM7TDMI RISC 128KB Flash 1.8V/3.3V 100-Pin LQFP
• Manufacturer: Atmel

Specifications of AT91SAM7X128

• Package: 100LQFP
• Device Core: ARM7TDMI
• Family Name: 91S
• Maximum Speed: 55 MHz
• Ram Size: 32 KB
• Program Memory Size: 128 KB
• Operating Supply Voltage: 1.8|3.3 V
• Data Bus Width: 32 Bit
• Program Memory Type: Flash
• Number Of Programmable I/os: 62
• Interface Type: CAN/Ethernet/SPI/I2S/TWI/USART/USB
• On-chip Adc: 8-chx10-bit
• Operating Temperature: -40 to 85 °C
• Number Of Timers: 3

22. Peripheral DMA Controller (PDC)
22.1
22.2
6120H–ATARM–17-Feb-09
Overview
Block Diagram
The Peripheral DMA Controller (PDC) transfers data between on-chip serial peripherals such as
the UART, USART, SSC, SPI, MCI and the on- and off-chip memories. Using the Peripheral
DMA Controller avoids processor intervention and removes the processor interrupt-handling
overhead. This significantly reduces the number of clock cycles required for a data transfer and,
as a result, improves the performance of the microcontroller and makes it more power efficient.
The PDC channels are implemented in pairs, each pair being dedicated to a particular periph-
eral. One channel in the pair is dedicated to the receiving channel and one to the transmitting
channel of each UART, USART, SSC and SPI.
The user interface of a PDC channel is integrated in the memory space of each peripheral. It
contains:
The peripheral triggers PDC transfers using transmit and receive signals. When the pro-
grammed data is transferred, an end of transfer interrupt is generated by the corresponding
peripheral.
Figure 22-1. Block Diagram
• A 32-bit memory pointer register
• A 16-bit transfer count register
• A 32-bit register for next memory pointer
• A 16-bit register for next transfer count
Peripheral
Control
THR
RHR
AT91SAM7X512/256/128 Preliminary
Status & Control
PDC Channel 0
PDC Channel 1
Peripheral DMA Controller
Control
Controller
Memory
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