MC68HC708XL36 FREESCALE [Freescale Semiconductor, Inc], MC68HC708XL36 Datasheet - Page 118

• Manufacturer Part Number: MC68HC708XL36
• Description: HCMOS Microcontroller Unit
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

DMA
MC68HC708XL36
118
ADDRESS
CGMOUT
STATE
DATA
BUS
BUS
R/W
Figure 4. Single Word Transfer Timing (100% DMA Bus Bandwidth)
State
10
1
2
3
4
5
6
7
8
9
1
DMA service request occurs.
DMA arbitrates channel priority.
DMA generates internal control signals.
DMA calculates source address.
DMA latches source address in temporary register.
DMA drives source address onto address bus.
DMA drives R/W line high.
DMA calculates destination address.
DMA latches destination address into temporary register.
DMA latches source data into temporary register.
DMA increments byte count register.
DMA drives destination address onto address bus.
DMA drives R/W line low.
DMA subtracts byte count register from block length register.
DMA drives source data onto data bus.
DMA releases address bus and R/W line to CPU.
DMA releases data bus to CPU.
2
CPU-CONTROLLED BUS CYCLE
If difference = 0, DMA disables channel by clearing TECx bit.
If difference = 0 and IECx = 1, DMA generates CPU interrupt request.
3
Freescale Semiconductor, Inc.
Table 2. DMA Byte Transfer Activity
For More Information On This Product,
4
5
Go to: www.freescale.com
6
7
DMA
Activity
8
9
10
11
DMA-CONTROLLED BUS CYCLE
12
13
14
15
MOTOROLA
16
8-dma_b