M30622M4 MITSUBISHI [Mitsubishi Electric Semiconductor], M30622M4 Datasheet - Page 36

• Manufacturer Part Number: M30622M4
• Description: SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
• Manufacturer: MITSUBISHI [Mitsubishi Electric Semiconductor]

Bus Control
36
Table 1.12.5. Microcomputer status in ready state (Note)
Note: The RDY signal cannot be received immediately prior to a software wait.
Figure 1.12.3. Example of RD signal extended by RDY signal
(5) The RDY signal
Oscillation
R/W signal, address bus, data bus, CS
ALE signal, HLDA, programmable I/O ports
Internal peripheral circuits
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RDY is a signal that facilitates access to an external device that requires long access time. As shown in
Figure 1.12.3, if an “L” is being input to the RDY at the BCLK falling edge, the bus turns to the wait state.
If an “H” is being input to the RDY pin at the BCLK falling edge, the bus cancels the wait state. Table
1.12.5 shows the state of the microcomputer with the bus in the wait state, and Figure 1.12.3 shows an
example in which the RD signal is prolonged by the RDY signal.
The RDY signal is valid when accessing the external area during the bus cycle in which bits 4 to 7 of the
chip select control register (address 0008
all bits 4 to 7 of the chip select control register (address 0008
properly as in non-using.
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In an instance of separate bus
In an instance of multiplexed bus
BCLK
RD
CS
(i=0 to 3)
RDY
BCLK
RD
CS
(i=0 to 3)
RDY
i
i
: Wait using software
: Wait using RDY signal
Item
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_____
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Accept timing of RDY signal
_____
tsu(RDY - BCLK)
16
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) are set to “0”. The RDY signal is invalid when setting “1” to
On
Maintain status when RDY signal received
On
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Accept timing of RDY signal
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tsu(RDY - BCLK)
16
________
), but the RDY pin should be treated as
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
Status
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Mitsubishi microcomputers
M16C / 62 Group