MC68030FE20C Freescale Semiconductor, MC68030FE20C Datasheet - Page 534

• Manufacturer Part Number: MC68030FE20C
• Description: IC MPU 32BIT ENHANCED 132-CQFP
• Manufacturer: Freescale Semiconductor

Specifications of MC68030FE20C

• Processor Type: M680x0 32-Bit
• Speed: 20MHz
• Voltage: 5V
• Mounting Type: Surface Mount
• Package / Case: 132-CQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Features: -

12.3 BYTE SELECT LOGIC FOR THE MC68030
MOTOROLA
The architecture of the MC68030 allows it to support byte, word, and long-
word operand transfers to any 8-, 16-, or 32-bit data port regardless of align-
the data transfer accordingly, using multiple bus cycles when necessary.
The following signals control the MC68030 operand transfer mechanism'
ment. This feature allows the programmer to write code that is not bus-width
specific. When accessed, the peripheral or memory subsystem reports its
actual port size to the processor, and the MC68030 then dynamically sizes
dependent of software prejudices. The following paragraphs describe the
generation of byte select control signals that enable the dynamic bus sizing
Hardware designers also have the flexibility to choose implementations in-
mechanism, the transfer of differently sized operands, and the transfer of
misaligned operands to operate correctly.
DSACKO/DSACK]
• A1, A0 = Address lines. The most significant byte of the operand to be
• S!Z1, SIZ0 = Transfer size. Output of the MC68030. These indicate the
• R/W = Read/Write. Output of the MC68030. For byte select generation
START
AS
data from the device is cachable.
in MC68030 systems, R/W must be included in the logic if the
transferred is addressed directly.
Figure 12-5. Bus Cycle Timing Diagram
number of bytes of an operand remaining to be transferred
during a given bus cycle.
MC68030 USER'S MANUAL
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FPCP SPECIFICATION
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MPU SPECIFICATION
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