M16C62_M Datasheet, PDF (556/615 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/60 SERIES

External Buses
Mitsubishi microcomputers
M16C / 62A Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
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(2) RDY function usage
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To use the RDY function, set a software wait.
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The RDY function operates when the BCLK signal falls with the RDY pin at “L”; the bus does not vary
for 1 BCLK, and the state at that moment is held.
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The RDY function holds the state of bus for the period in which the RDY pin is at “L”, and releases it
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when the BCLK signal falls with the RDY pin at “H”. Figure 4.4.6 shows an example of RDY circuit
that holds the state of bus for 1 BCLK.
BCLK
S
S
CK
1Q
CK
2Q
RDY
D
1Q
R
D
2Q
R
CS0
RD
• Timings in separate bus
BCLK
CS0
RD
1Q
2Q
RDY
• Timings in multiplex bus
BCLK
CS0
RD
1Q
2Q
RDY
(1)
(2)
(1)
(2)
(1)
(2)
(1)
(2)
(1) RDY accepted
(2) RDY cleared
The state of data bus and that of address bus are held for the period between (1) and (2).
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Figure 4.4.6. Example of RDY circuit holding state of bus for 1 BCLK
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