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4.17 Bus Timing
4.17.21 External Bus Request
This section provides external bus request timing charts.
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Bus Control Release
Figure 4.17-38 Example of Bus Control Release Timing Chart
[Explanation of operation]
• When performing bus arbitration by BRQ and BGRNTX, set the BRE bit of EPCR0 to "1".
• When releasing bus control, set the corresponding pins to High-Z and assert BGRNTX one
cycle later.
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Bus Control Acquisition
Figure 4.17-39 Example of Bus Control Acquisition Timing
[Explanation of operation]
• When performing bus arbitration by BRQ and BGRNTX, set the BRE bit of EPCR0 to "1".
• When acquiring bus control, negate BGRNTX and activate each pin one clock later.
CLK
A24-00 #0:1 high
Z
D31-16 #0:1 high Z
RDX high Z
BRQ
BGRNTX
1 cycle
CLK
A24-00 high Z
D31-16 high Z
RDX high Z
BRQ
BGRNTX
1 cycle