r4f2456 Renesas Electronics Corporation., r4f2456 Datasheet - Page 287

• Manufacturer Part Number: r4f2456
• Description: 16-bit Single-chip Microcomputer H8s Family / H8s/2400 Series
• Manufacturer: Renesas Electronics Corporation.

6.8.11
When synchronous DRAM with a ×16-bit configuration is connected, DQMU and DQML are
used for the control signals needed for byte access.
Figures 6.61 and 6.62 show the control timing for DQM, and figure 6.63 shows an example of
connection of byte control by DQMU and DQML.
Upper data bus
Lower data bus
Precharge-sel
Address bus
Byte Access Control
SDRAMφ
DQMU
DQML
CKE
RAS
CAS
WE
φ
(Upper Byte Write Access: SDWCD = 0, CAS Latency 2)
Figure 6.61 DQMU and DQML Control Timing
Column address
PALL
T
p
Row address
Row address
ACTV
T
r
High
High
NOP
T
c1
Rev. 1.00 Sep. 19, 2008 Page 257 of 1342
High impedance
Column address
WRIT
T
cl
Section 6 Bus Controller (BSC)
NOP
T
c2
REJ09B0467-0100