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10.1.11 DMA Module Integration .......................................................................................10-12
10.1.11.1
DMA Unit Structure .....................................................................................10-13
10.2
PROGRAMMING THE DMA UNIT ............................................................................ 10-15
10.2.1
DMA Channel Parameters ....................................................................................10-15
10.2.1.1
Programming the Source and Destination Pointers ....................................10-15
10.2.1.2
Selecting Byte or Word Size Transfers ........................................................10-19
10.2.1.3
Selecting the Source of DMA Requests ......................................................10-22
10.2.1.4
Arming the DMA Channel ............................................................................10-23
10.2.1.5
Selecting Channel Synchronization .............................................................10-23
10.2.1.6
Programming the Transfer Count Options ...................................................10-24
10.2.1.7
Generating Interrupts on Terminal Count ....................................................10-25
10.2.1.8
Setting the Relative Priority of a Channel ....................................................10-26
10.2.2
Setting the Inter-Module Priority ...........................................................................10-26
10.2.3
Using the DMA Unit with the Serial Ports ..............................................................10-26
10.2.4
Suspension of DMA Transfers Using the DMA Halt Bits .......................................10-27
10.2.5
Initializing the DMA Unit ........................................................................................10-27
10.3
HARDWARE CONSIDERATIONS AND THE DMA UNIT ......................................... 10-28
10.3.1
DRQ Pin Timing Requirements .............................................................................10-29
10.3.2
DMA Latency ........................................................................................................10-29
10.3.3
DMA Transfer Rates .............................................................................................10-29
10.3.4
Generating a DMA Acknowledge ..........................................................................10-30
10.4
DMA UNIT EXAMPLES ............................................................................................. 10-30
CHAPTER 11
SERIAL COMMUNICATIONS UNIT
11.1
INTRODUCTION ......................................................................................................... 11-1
11.1.1
Asynchronous Communications ..............................................................................11-1
11.1.1.1
RX Machine ...................................................................................................11-2
11.1.1.2
TX Machine ...................................................................................................11-4
11.1.1.3
Modes 1, 3 and 4 ...........................................................................................11-6
11.1.1.4
Mode 2 ..........................................................................................................11-7
11.1.2
Synchronous Communications ...............................................................................11-8
11.2
PROGRAMMING ......................................................................................................... 11-9
11.2.1
Baud Rates ...........................................................................................................11-10
11.2.2
Asynchronous Mode Programming .......................................................................11-13
11.2.2.1
Modes 1, 3 and 4 for Stand-alone Serial Communications .........................11-13
11.2.2.2
Modes 2 and 3 for Multiprocessor Communications ...................................11-14
11.2.2.3
Sending and Receiving a Break Character .................................................11-14
11.2.3
Programming in Mode 0 ........................................................................................11-18
11.3
HARDWARE CONSIDERATIONS FOR THE SERIAL PORT ................................... 11-18
11.3.1
CTS Pin Timings ...................................................................................................11-18
11.3.2
BCLK Pin Timings .................................................................................................11-18
11.3.3
Mode 0 Timings ....................................................................................................11-20
11.3.3.1
CLKOUT as Baud Timebase Clock .............................................................11-20
11.3.3.2
BCLK as Baud Timebase Clock ..................................................................11-21
CONTENTS
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