M30622SAFP MITSUBISHI [Mitsubishi Electric Semiconductor], M30622SAFP Datasheet - Page 30

• Manufacturer Part Number: M30622SAFP
• Description: SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
• Manufacturer: MITSUBISHI [Mitsubishi Electric Semiconductor]

Bus Control
30
Table 1.9.5. Microcomputer status in ready state (Note)
Note: The RDY signal cannot be received immediately prior to a software wait.
Figure 1.9.3. 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 1.9.3, 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 1.9.5
shows the state of the microcomputer with the bus in the wait state, and Figure 1.9.3 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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__________
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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
_____
________
Accept timing of RDY signal
_____
________
tsu(RDY - BCLK)
16
________
) are set to “0”. The RDY signal is invalid when setting “1” to
________
On
Maintain status when RDY signal received
On
Accept timing of RDY signal
tsu(RDY - BCLK)
16
________
), but the RDY pin should be treated as
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
Status
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M16C / 62A Group
Mitsubishi microcomputers