Datasheet

Section 6 Bus Controller (BSC)
Rev.6.00 Mar. 18, 2009 Page 152 of 980
REJ09B0050-0600
6.5.2 Valid Strobes
Table 6.3 shows the data buses used and valid strobes for the access spaces.
In a read, the RD signal is valid for both the upper and the lower half of the data bus. In a write,
the HWR signal is valid for the upper half of the data bus, and the LWR signal for the lower half.
Table 6.3 Data Buses Used and Valid Strobes
Area
Access
Size
Read/
Write Address
Valid
Strobe
Upper Data Bus
(D15 to D8)
Lower Data Bus
(D7 to D0)
8-bit access Byte Read — RD Valid Invalid
space
Write — HWR Hi-Z
16-bit access Byte Read Even RD Valid Invalid
space
Odd Invalid Valid
Write Even HWR Valid Hi-Z
Odd LWR Hi-Z Valid
Word Read — RD Valid Valid
Write — HWR, LWR Valid Valid
Notes: Hi-Z: High-impedance state
Invalid: Input state; input value is ignored.