CHAPTER 6 BUS CONTROL
User’s Manual U14272EJ3V0UM
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6.3.4 External ROM cycles
The following timing diagrams illustrate the external ROM cycles depending on the settings in the bus control
register and bus speed control register.
(1) Ordinary ROM read cycle
Figure 6-3. Ordinary ROM Read Cycle (WROMA(3:0) = 0101)
TClock
(internal)
ADD(21:0)
(output)
MEMRD#
(output)
DATA(15:0)
(read)
ROMCS(3:0)#
(output)
WROMA(3:0)
Valid
Valid
Remark
A circle in the figure indicates the sampling timing.