SH7032 Datasheet, PDF (165/687 Pages) Renesas Technology Corp – 32-Bit RISC Microcomputer

Section 8 Bus State Controller (BSC)
8.4 Accessing External Memory Space
In external memory space, a strobe signal is output based on the assumption of a directly
connected SRAM. The external memory space is allocated to the following areas:
• Area 0 (when MD2–MD0 are 000 or 001)
• Area 1 (when the DRAM enable bit (DRAME) in BCR is 0)
• Areas 2–4
• Area 5 (space where address bit A27 is 1)
• Area 6 (when the multiplexed I/O enable bit (IOE) bit in BCR is 0, or space where address bit
A27 is 1)
• Area 7 (space where address bit A27 is 0)
8.4.1 Basic Timing
The bus cycle for external memory space access is 1 or 2 states. The number of states is controlled
with wait states by the settings of wait state control registers 1–3 (WCR1–WCR3). For details, see
section 8.4.2, Wait State Control. Figures 8.11 and 8.12 illustrate the basic timing of external
memory space access.
T1
CK
A21–A0
CSn
RD
(Read)
AD15–AD0
(Read)
Figure 8.11 Basic Timing of External Memory Space Access (1-State Read Timing)
Rev. 7.00 Jan 31, 2006 page 139 of 658
REJ09B0272-0700