UM10208_2
© NXP B.V. 2007. All rights reserved.
User manual
Rev. 02 — 1 June 2007
178 of 362
NXP Semiconductors
UM10208
Chapter 15: LPC2800 GPDMA
3.1 GPDMA functional description
The GPDMA enables peripheral-to-memory, memory-to-peripheral, peripheral-to-
peripheral, and memory-to-memory transactions. Each DMA channel can provide
unidirectional DMA transfers for a single source and destination. For example, a
bidirectional peripheral may need one channel for transmit and one for receive. The
source and destination areas can each be either a memory region or a peripheral, and
can be accessed through the AHB master, which can access peripherals on any of the
APBs.
shows a block diagram of the GPDMA.
3.1.1 APB slave interface
All GPDMA registers should be read and written using word (32 bit) operations.
3.1.2 Bus and transfer widths
The physical width of the AHB bus is 32 bits. Source and destination transfers must be of
the same width: 8, 16, or 32 bits.
3.1.3 Endian behavior
GPDMA channels can swap bytes between a big-endian source and a little-endian
destination, or between a little-endian source and a big-endian destination.
3.1.4 Error conditions
A peripheral can assert an Error response on the AHB bus during a transfer. A memory
can assert an Abort response during a transfer, indicating that the requested address
does not exist or perhaps that its contents failed integrity checking such as parity or ECC.
The GPDMA includes a single centralized status bit for Abort notification.
Fig 25. GPDMA block diagram
GPDMA
APB SLAVE
INTERFACE
CONTROL
LOGIC AND
REGISTERS
DMA
REQUEST
AND
RESPONSE
INTERFACE
CHANNEL
LOGIC AND
REGISTERS
INTERRUPT
REQUEST
AHB
MASTER
INTERFACE
DMA
requests
DMA
responses
DMA
Interrupts
APB BUS
AHB BUS