Memory Interface
1-10
2 summarizes how these buses are used during accesses.
Table 1
−
2. Summary of Bus Use During Data-Space and Program-Space Accesses
ÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁ
Access Type
ÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁ
Address Bus
ÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁ
Data Bus
ÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁ
Read from program space
PAB
ÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁ
PRDB
ÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁ
Read from data space
ÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁ
DRAB
ÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁ
DRDB
ÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁ
Write to program space
PAB
DWDB
ÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁ
Write to data space
ÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁ
DWAB
DWDB
A program-space read and a program-space write cannot happen simulta-
neously because both use the PAB. Similarly, a program-space write and a
data-space write cannot happen simultaneously because both use the DWDB.
Transactions that use different buses can happen simultaneously. For exam-
ple, the CPU can read from program space (using PAB and PRDB), read from
data space (using DRAB and DRDB), and write to data space (using DWAB
and DWDB) at the same time.
1.4.2 Special Bus Operations
Typically, PAB and PRDB are used only for reading instructions from program
space, and DWDB is used only for writing data to data space. However, the
instructions in Table 1
3 are exceptions to this behavior. For more details
about using these instructions, see Chapter 6,
Assembly Language Instruc-
tions
.
Содержание TMS320C28x
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Страница 269: ...IN loc16 PA 6 112 MOV AL 0 AL 0 UOUT IORegC AL IOspace IORegC AL 10...
Страница 308: ...MAXCUL P loc32 6 151 Saturate MOVL Var64 2 ACC Store result into Var64 MOVL Var64 P...
Страница 509: ...SUBL ACC P PM 6 352 SUBL ACC P PM ACC S B 11 M X 4 MOVH Y ACC 5 Store Q15 result into Y...
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