SH7708 Datasheet, PDF (247/633 Pages) Renesas Technology Corp – SuperH™ RISC engine

10.3.2 Description of Areas
Area 0: Area 0 physical address bits A28–A26 are 000. Address bits A31–A29 are ignored and
the address range is H'00000000 + H'20000000 × n – H'03FFFFFF + H'20000000 × n (n = 0–6, n
= 1–6 is the shadow space).
Normal memories such as SRAM, ROM, and burst ROM can be connected to this space. Byte,
word, or longword can be selected as the bus width using external pins. MD3 and MD4 on a
power-on reset. For details, see Memory Size in section 10.1.5. When the Area 0 space is
accessed, the CS0 signal is asserted. The RD signal that can be used as OE and the WE0–WE3
signals for write control are also asserted. The number of bus cycles is selected between 0 and 10
wait cycles using the A0W2–A0W0 bits in WCR2. Also, any number of waits can be inserted in
each bus cycle by means of the external wait pin (WAIT). When the burst function is used, the bus
cycle pitch of the burst cycle is determined within a range of 2–10 according to the number of
waits.
Area 1: Area 1 physical address bits A28–A26 are 001. Address bits A31–A29 are ignored and
the address range is H'04000000 + H'20000000 × n – H'07FFFFFF + H'20000000 × n (n = 0–6, n
= 1–6 is the shadow space).
Only normal memories like SRAM and ROM can be connected to this space. Byte, word, or
longword can be selected as the bus width using the A1SZ1–A1SZ0 bits in BCR2. When the Area
1 space is accessed, the CS1 signal is asserted. The RD signal that can be used as OE and the
WE0–WE3 signals for write control are also asserted. The number of bus cycles is selected
between 0 and 3 wait cycles using the A12W1–A12W0 bits in WCR2. Also, any number of waits
can be inserted in each bus cycle by means of the external wait pin (WAIT).
Area 2: Area 2 physical address bits A28–A26 are 010. Address bits A31–A29 are ignored and
the address range is H'08000000 + H'20000000 × n – H'0BFFFFFF + H'20000000 × n (n = 0–6, n
= 1–6 is the shadow space).
Normal memories like SRAM and ROM, as well as DRAM and synchronous DRAM, can be
connected to this space. Byte, word, or longword can be selected as the bus width using the
A2SZ1–A2SZ0 bits in BCR2 for normal memory. For synchronous DRAM, set longword using
the SZ bit in MCR. When DRAM is connected to area 2, the bus width is fixed at 16 bits. The bus
width for area 3 also needs to be 16 bits.
When the area 2 space is accessed, the CS2 signal is asserted. When normal memories are
connected, the RD signal that can be used as OE and the WE0–WE3 signals for write control are
also asserted and the number of bus cycles is selected between 0 and 3 wait cycles using the
A12W1 to A12W0 bits in WCR2. When normal memory is connected, only, any number of waits
can be inserted in each bus cycle by means of the external wait pin (WAIT).
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