PIC24HJ64GP506-I Datasheet, PDF (31/292 Pages) Microchip Technology – High-Performance, 16-Bit Microcontrollers

PIC24HJXXXGPX06/X08/X10
FIGURE 4-4:
DATA MEMORY MAP FOR PIC24HJXXXGPX06/X08/X10 DEVICES WITH 16 KBS
RAM
2 Kbyte
SFR Space
16 Kbyte
SRAM Space
MSB
Address
0x0001
0x07FF
0x0801
0x1FFF
16 bits
MSB
LSB
SFR Space
X Data RAM (X)
LSB
Address
0x0000
0x07FE
0x0800
0x1FFE
8 Kbyte
Near
Data
Space
0x3FFF
0x4001
0x47FF
0x4801
DMA RAM
0x3FFE
0x4000
0x47FE
0x4800
0x8001
Optionally
Mapped
into Program
Memory
X Data
Unimplemented (X)
0x8000
0xFFFF
0xFFFE
4.2.5 DMA RAM
Every PIC24HJXXXGPX06/X08/X10 device contains 2
Kbytes of dual ported DMA RAM located at the end of
data space. Memory locations in the DMA RAM space
are accessible simultaneously by the CPU and the DMA
controller module. DMA RAM is utilized by the DMA
controller to store data to be transferred to various
peripherals using DMA, as well as data transferred from
© 2009 Microchip Technology Inc.
various peripherals using DMA. The DMA RAM can be
accessed by the DMA controller without having to steal
cycles from the CPU.
When the CPU and the DMA controller attempt to
concurrently write to the same DMA RAM location, the
hardware ensures that the CPU is given precedence in
accessing the DMA RAM location. Therefore, the DMA
RAM provides a reliable means of transferring DMA
data without ever having to stall the CPU.
Note:
DMA RAM can be used for general
purpose data storage if the DMA function
is not required in an application.
DS70175H-page 29