Usage Notes - Renesas H8/3067 Series User Manual

Section 6 Bus Controller
Example of Program Setup Procedure: Figure 6.34 shows an example of the program setup
procedure.
Figure 6.34 Example of Setup Procedure when Using DRAM Interface
6.5.13

Usage Notes

Note the following points when using the DRAM refresh function.
• Refresh cycles will not be executed when the external bus released state, software standby
mode, or a bus cycle is extended by means of wait state insertion. Refreshing must therefore be
performed by other means in these cases.
• If a refresh request is generated internally while the external bus is released, the first request is
retained and a single refresh cycle will be executed after the bus-released state is cleared.
Figure 6.35 shows the bus cycle in this case.
• When a bus cycle is extended by means of wait state insertion, the first request is retained in
the same way as when the external bus has been released.
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REJ09B0276-0400
Set ABWCR
Set RTCOR
Set bits CKS2 to CKS0 in RTMCSR
Set DRCRB
Set DRCRA
Wait for DRAM stabilization time
DRAM can be accessed