z16f2811 ZiLOG Semiconductor, z16f2811 Datasheet - Page 286

• Manufacturer Part Number: z16f2811
• Description: High Performance Microcontrollers
• Manufacturer: ZiLOG Semiconductor

PS022006-0207
Direct DMA Setup and Operation
Follows the steps below to setup the DMA in direct mode:
1. Write the
2. Write the DMAxDAR register with the destination address.
3. Write the DMAxSAR register with the source address.
4. Write the DMAxTXLN with the transfer length.
5. Write DMAxLARU with water mark if required, otherwise write to zero.
6. Write DMAxCTL. Note the control register and address are directly written with word
7. The DMA is now set up and begins operating when it receives a request.
Once the DMA is set up and a request is received the DMA does the following:
1. Generate a request to the CPU.
2. It transfers data for each request until the transfer length reaches zero or the DMA
3. When the DMA receives the Request EOF signal, or the transfer length reaches zero it
and quad operations.
–
–
–
–
–
–
–
–
–
–
receives a Request EOF signal.
resets the
If
CMDSTAT field of the DMAxCTL register. If the
with a Request EOF the DMA channel generates a request to the CPU.
If
CPU.
EOF
EOF
DMAxEN, set to one.
LOOP, reset to zero, not used in this mode
TXSIZE, set to the transfer size, byte, word or quad.
DSTCTL, set to fixed, increment, or decrement.
SRCCTL, set to fixed, increment, or decrement.
IEOB, set to one to generate an interrupt at the end of buffer or water mark.
TXFR, reset to zero, not used in this mode.
EOF, set this bit to one if this is an EOF buffer.
HALT, reset to zero, not used in this mode.
CMDSTAT, set these bits with the command for the peripheral.
is set then the DMA reads the status from the peripheral and places it in the
is not set and
DAMxREQSEL
DMAxEN
bit and then does the following based upon the
IEOB
P R E L I M I N A R Y
to select the request source.
is set then the DMA channel generates a request to the
IEOB
bit is set or the buffer ended
Product Specification
ZNEO
EOF
™
DMA Controller
and
Z16F Series
IEOB
bits.
272