HD6412373R RENESAS [Renesas Technology Corp], HD6412373R Datasheet - Page 299

• Manufacturer Part Number: HD6412373R
• Description: Renesas 16-Bit Single-Chip Microcomputer H8S Family/H8S/2300 Series
• Manufacturer: RENESAS [Renesas Technology Corp]

Section 6 Bus Controller (BSC)
6.7.12
Burst Operation
With synchronous DRAM, in addition to full access (normal access) in which data is accessed by
outputting a row address for each access, burst access is also provided which can be used when
making consecutive accesses to the same row address. This access enables fast access of data by
simply changing the column address after the row address has been output. Burst access can be
selected by setting the BE bit to 1 in DRAMCR.
DQM has the 2-cycle latency when synchronous DRAM is read. Therefore, the DQM signal
cannot be specified to the Tc2 cycle data output if Tc1 cycle is performed for second or following
column address when the CAS latency is set to 1 to issue the READ command. Do not set the BE
bit to 1 when synchronous DRAM of CAS latency 1 is connected.
Burst Access Operation Timing: Figure 6.52 shows the operation timing for burst access. When
there are consecutive access cycles for continuous synchronous DRAM space, the column address
output cycles continue as long as the row address is the same for consecutive access cycles. The
row address used for the comparison is set with bits MXC2 to MXC0 in DRAMCR.
Rev.7.00 Mar. 18, 2009 page 231 of 1136
REJ09B0109-0700