SH7032 Datasheet, PDF (137/687 Pages) Renesas Technology Corp – 32-Bit RISC Microcomputer

Section 8 Bus State Controller (BSC)
8.2.2 Wait State Control Register 1 (WCR1)
Wait state control register 1 is a 16-bit read/write register that controls the number of states for
accessing each area and whether wait states are used. WCR1 is initialized to H'FFFF by a power-
on reset. It is not initialized by a manual reset or in standby mode.
Bit
Initial value
Read/Write
15
RW7
1
R/W
14
RW6
1
R/W
13
RW5
1
R/W
12
RW4
1
R/W
11
RW3
1
R/W
10
RW2
1
R/W
9
RW1
1
R/W
8
RW0
1
R/W
Bit
Initial value
Read/Write
7
6
5
4
3
2
1
0
—
—
—
—
—
—
WW1
—
1
1
1
1
1
1
1
1
—
—
—
—
—
—
R/W
—
Bits 15–8—Wait State Control During Read (RW7–RW0): RW7–RW0 determine the number
of states in read cycles for each area and whether or not to sample the signal input from the WAIT
pin. Bits RW7–RW0 correspond to areas 7–0, respectively. If a bit is cleared to 0, the WAIT
signal is not sampled during the read cycle for the corresponding area. If it is set to 1, sampling
takes place.
For the external memory spaces of areas 1, 3–5, and 7, read cycles are completed in one state
when the corresponding bits are cleared to 0. When they are set to 1, the number of wait states is 2
plus the WAIT signal value. For the external memory space of areas 0, 2, and 6, read cycles are
completed in one state plus the number of long wait states (set in wait state controller 3 (WCR3))
when the corresponding bits are cleared to 0. When they are set to 1, the number of wait states is 1
plus the long wait state; when the WAIT signal is low as well, a wait state is inserted.
The DRAM space (area 1) finishes the column address output cycle in one state (short pitch) when
the RW1 bit is 0, and in 2 states plus the WAIT signal value (long pitch) when RW1 is 1. When
RW1 is set to 1, the number of wait states selected in wait state insertion bits 1 and 0 (RLW0 and
RLW1) for CAS-before-RAS (CBR) refresh in the refresh control register (RCR) are inserted
during the CBR refresh cycle, regardless of the status of the WAIT signal.
The read cycle of the address/data multiplexed I/O space (area 6) is 4 states plus the wait states
from the WAIT signal, regardless of the setting of the RW6 bit. The read cycle of the on-chip
supporting module space (area 5) finishes in 3 states, regardless of the setting of the RW5 bit, and
the WAIT signal is not sampled. The read cycles of on-chip ROM (area 0) and on-chip RAM (area
Rev. 7.00 Jan 31, 2006 page 111 of 658
REJ09B0272-0700