DSP56309EVM Freescale Semiconductor, DSP56309EVM Datasheet - Page 97

• Manufacturer Part Number: DSP56309EVM
• Description: KIT EVALUATION FOR XC56309
• Manufacturer: Freescale Semiconductor
• Type: DSPr

Specifications of DSP56309EVM

• Contents: Module Board, Installation Guide, Power Supply, Cable, Software and more
• Description/function: Audio DSPs
• Product: Audio Modules
• For Use With/related Products: DSP56309
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Example 5-3 shows a DMA configuration for transferring data to the Host Transmit register of
the HI08.
DMA requires more initialization code and consideration of DMA modes. However, it is the
most efficient use of core resources. Once these registers are programmed, you must enable the
DMA by triggering a DMA request off one of the peripheral control flags or enabling it in normal
program flow or an interrupt service routine.
5.4.4 Advantages and Disadvantages
Polling is the easiest method to implement, but it requires a large amount of DSP56309 core
processing power. The core cannot be involved in other processing activities while it is polling
receive and transmit ready bits. Interrupts require more code, but the core can process other
routines while waiting for data I/O. An interrupt is generated when data is ready to be transferred
to or from the peripheral device. DMA requires even less core intervention, and the setup code is
minimal, but the DMA channels must be available.
Note:
Freescale Semiconductor
bclr#M_D1L0,x:M_IPRC
bclr#M_D1L1,x:M_IPRC
movep#TBUFF_START,x:M_DSR1 ; DMA1 source is transmit buffer
movep#M_HTX,x:M_DDR1
movep#TBUFF_SIZE-1,x:M_DCO1; DMA1 count is the full buffer
movep#INIT_DCR1,x:M_DCR1
Do not use interrupt requests and DMA requests simultaneously.
EFCOP
Block
Timer
ESSI
HI08
SCI
Table 5-1. DMA-Accessible Registers
; disable DMA1 interrupts
; DMA1 destination is HTX
; init. DMA1 control register
Example 5-3. DMA Transfers
DSP56309 User’s Manual, Rev. 1
Register
FDOR
FDIR
SRX
HRX
STX
HTX
TX0
TX1
TX2
RX
Read
Yes
Yes
Yes
Yes
No
No
No
No
No
No
DMA
Data Transfer Methods
Write
Yes
Yes
Yes
Yes
Yes
Yes
No
No
No
No
5-5