SH7706 Datasheet, PDF (265/749 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperH™ RISC engine Family/SH7700 Series

Section 8 Bus State Controller (BSC)
Figure 8.14 shows the burst read timing when RCD is set to 1, A3W1 and A3W0 are set to 10, and
TPC is set to 1.
The BS cycle, which is asserted for one cycle at the start of a bus cycle for normal space access, is
asserted in each of cycles Td1 to Td4 in a synchronous DRAM cycle. When a burst read is
performed, the address is updated each time CAS is asserted. As the unit of burst transfer is 16
bytes, address updating is performed for A3 and A2 only (A3, A2, and A1 for a 16-bit bus width).
The order of access is as follows: in a fill operation in the event of a cache miss, the missed data is
read first, then 16-byte boundary data including the missed data is read in wraparound mode.
CKIO
Address
upper bits
A12 or A11^*1
Address
lower bits^*2
CS2 or CS3
RASx
CASx
RD/WR
DQMxx
Tr
Trw
Tc1
Tc2 Tc3/Td1 Tc4/Td2 Td3
Td4
Tpc
D31 to D0
BS
Notes: 1. Command bit
2. Column address
Figure 8.14 Synchronous DRAM Burst Read Wait Specification Timing
Rev. 5.00 May 29, 2006 page 217 of 698
REJ09B0146-0500