70592C Datasheet, PDF (37/314 Pages) Microchip Technology – High-Performance, 16-bit Microcontrollers

PIC24HJXXXGPX06A/X08A/X10A
FIGURE 4-4:
DATA MEMORY MAP FOR PIC24HJXXXGPX06A/X08A/X10A DEVICES WITH 16 KB 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 PIC24HJXXXGPX06A/X08A/X10A 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 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.
© 2011 Microchip Technology Inc.
DS70592C-page 37