CHAPTER 2 PIN FUNCTIONS
User’s Manual U13850EJ6V0UD
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(v)
ASTB (Address strobe) ··· output
This is an output pin for the external address bus’s latch strobe signal. Output becomes active (low
level) in synchronization with the falling edge of the clock during the T1 state of the bus cycle, and
becomes inactive (high level) in synchronization with the falling edge of the clock during the T3 state of
the bus cycle. Output becomes inactive when the timing sets the bus cycle as inactive.
(vi) HLDAK (Hold acknowledge) ··· output
This is an output pin for the acknowledge signal that indicates high impedance status for the address
bus, data bus, and control bus when the V850/SB1 and V850/SB2 receive a bus hold request.
The address bus, data bus, and control bus are set to high impedance status when this signal is active.
(vii) HLDRQ (Hold request) ··· input
This is an input pin by which an external device requests the V850/SB1 and V850/SB2 to release the
address bus, data bus, and control bus. This pin accepts asynchronous input for CLKOUT. When this
pin is active, the address bus, data bus, and control bus are set to high impedance status. This occurs
either when the V850/SB1 and V850/SB2 complete execution of the current bus cycle or immediately if
no bus cycle is being executed, then the HLDAK signal is set as active and the bus is released.
(viii) WRL (Write strobe low level data) ··· output
This is a write strobe signal output pin for the lower data in the external 16-bit data bus. Output occurs
during the write cycle, similar to DSTB.
(ix) WRH (Write strobe high level data) ··· output
This is a write strobe signal output pin for the higher data in the external 16-bit data bus. Output occurs
during the write cycle, similar to DSTB.
(x)
RD (Read strobe) ··· output
This is a read strobe signal output pin for the external 16-bit data bus. Output occurs during the read
cycle, similar to DSTB.
Содержание V850/SB1
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