DMA Operation
625
SLAU356I – March 2015 – Revised June 2019
Copyright © 2015–2019, Texas Instruments Incorporated
DMA
11.2.2.1 Transfer Types
The controller supports only SINGLE AHB-LITE transfers and has no support for any kind of BURST
transfer as defined in the AMBA3 AHB-Lite protocol.
11.2.2.2 Transfer Data Width
The controller supports data transfer sizes of 8, 16, or 32 bits. The transfer size for the source needs to be
the same as the size of the destination.
The controller always uses 32-bit data transfers when it accesses a channel control data structure.
11.2.2.3 Protection Control
The AHB-Lite protection control signals HPROT[3:1] indicate the following protection states:
•
Cacheable
•
Bufferable
•
Privileged
NOTE:
Although these protection options are available in the DMA, the peripherals in MSP432P4xx
do not differentiate access based on any of the above qualifiers.
lists the HPROT signal encoding.
(1)
The controller ties HPROT[0] HIGH, to indicate a data access.
Table 11-1. Protection Signaling
HPROT[3]
Cacheable
HPROT[2]
Bufferable
HPROT[1]
Privileged
HPROT[0]
Data/
Opcode
Description
–
–
–
1
(1)
Data access
–
–
0
–
User access
–
–
1
–
Privileged access
–
0
–
–
Non-bufferable
–
1
–
–
Bufferable
0
–
–
–
Non-cacheable
1
–
–
–
Cacheable
For each DMA cycle, the source transfer and destination transfer can be configured to use different
protection control settings.
11.2.2.4 Address Increments
Configure the address increments that the controller uses when it reads the source data or when it writes
the destination data. The increments available depend on the size of data packet being transferred.
lists the possible combinations.
The minimum address increment must always be equal in size to the width of the data packet. The
maximum address increment that the controller permits is 32 bits.
Table 11-2. Address Increments
Packet Data Width (bits)
Size of Address Increment
8
byte, halfword, or word
16
halfword or word
32
word