Datasheet

 2009-2012 Microchip Technology Inc. DS70591E-page 177
dsPIC33FJ32GS406/606/608/610 and dsPIC33FJ64GS406/606/608/610
8.0 DIRECT MEMORY ACCESS
(DMA)
Direct Memory Access (DMA) is a very efficient
mechanism of copying data between peripheral SFRs
(e.g., the UART Receive register and Input Capture 1
buffer) and buffers or variables stored in RAM, with
minimal CPU intervention. The DMA Controller
(DMAC) can automatically copy entire blocks of data
without requiring the user software to read or write the
peripheral Special Function Registers (SFRs) every
time a peripheral interrupt occurs. The DMA Controller
uses a dedicated bus for data transfers and, therefore,
does not steal cycles from the code execution flow of
the CPU. To exploit the DMA capability, the
corresponding user buffers or variables must be
located in DMA RAM.
The peripherals that can utilize DMA are listed in
Table 8-1 along with their associated Interrupt Request
(IRQ) numbers.
TABLE 8-1: DMA CONTROLLER CHANNEL TO PERIPHERAL ASSOCIATIONS
Note 1: This data sheet summarizes the features
of the dsPIC33FJ32GS406/606/608/610
and dsPIC33FJ64GS406/606/608/610
family of devices. However, it is not
intended to be a comprehensive reference
source. To complement the information in
this data sheet, refer to Section 22.
“Direct Memory Access (DMA)”
(DS70182) in the “dsPIC33F/PIC24H
Family Reference Manual”, which is
available from the Microchip web site
(www.microchip.com).
2: Some registers and associated bits
described in this section may not be
available on all devices. Refer to
Section 4.0 “Memory Organization” in
this data sheet for device-specific register
and bit information.
Note: The DMA module is not available on
dsIPC33FJ32GS406/606/608/610 and
dsPIC33FJ64GS406 devices.
Peripheral to DMA Association
DMAxREQ Register
IRQSEL<6:0> Bits
DMAxPAD Register
Values to Read from
Peripheral
DMAxPAD Register
Values to Write to
Peripheral
INT0 – External Interrupt 0 0000000 ——
IC1 – Input Capture 1 0000001 0x0140 (IC1BUF) —
IC2 – Input Capture 2 0000101 0x0144 (IC2BUF) —
IC3 – Input Capture 3 0100101 0x0148 (IC3BUF) —
IC4 – Input Capture 4 0100110 0x014C (IC4BUF) —
OC1 – Output Compare 1 Data 0000010 — 0x0182 (OC1R)
OC1 – Output Compare 1 Secondary Data 0000010 — 0x0180 (OC1RS)
OC2 – Output Compare 2 Data 0000110 — 0x0188 (OC2R)
OC2 – Output Compare 2 Secondary Data 0000110 — 0x0186 (OC2RS)
OC3 – Output Compare 3 Data 0011001 — 0x018E (OC3R)
OC3 – Output Compare 3 Secondary Data 0011001 — 0x018C (OC3RS)
OC4 – Output Compare 4 Data 0011010 — 0x0194 (OC4R)
OC4 – Output Compare 4 Secondary Data 0011010 — 0x0192 (OC4RS)
TMR2 – Timer2 0000111 ——
TMR3 – Timer3 0001000 ——
TMR4 – Timer4 0011011 ——
TMR5 – Timer5 0011100 ——
SPI1 – Transfer Done 0001010 0x0248 (SPI1BUF) 0x0248 (SPI1BUF)
SPI2 – Transfer Done 0100001 0x0268 (SPI2BUF) 0x0268 (SPI2BUF)
UART1RX – UART1 Receiver 0001011 0x0226 (U1RXREG) —
UART1TX – UART1 Transmitter 0001100 — 0x0224 (U1TXREG)
UART2RX – UART2 Receiver 0011110 0x0236 (U2RXREG) —
UART2TX – UART2 Transmitter 0011111 — 0x0234 (U2TXREG)
ECAN1 – RX Data Ready 0100010 0x0640 (C1RXD) —
ECAN1 – TX Data Request 1000110 — 0x0642 (C1TXD)