pc87307 National Semiconductor Corporation, pc87307 Datasheet - Page 179

• Manufacturer Part Number: pc87307
• Description: Plug And Play Compatible And Pc97 Compliant Superi/o
• Manufacturer: National Semiconductor Corporation

10.0 X-Bus Data Buffer
10.1 FUNCTIONAL OVERVIEW
The X-Bus Data Buffer (XDB) connects the 8-bit X data bus
to the system data bus via the data bus of the
PC87307/PC97307.
The XDB is selected by bit 4 of Super/O Chip Configuration
1 register (index 21h), as described in Section 2.4.3 on
page 34. This bit is initialized according to the CFG1 strap
pin value.
10.2 MAPPING
When XDB is not selected, these pins have alternate func-
tions. See the XDB pin multiplexing in Table 1-2 on page 23.
When XDCS is inactive, XD7-0 are neither driven nor gated
to D7-0.
When XDCS is active XD7-0, are linked to D7-0 as follows:
•
•
D7-0 values are driven onto XD7-0 pins when XDRD
is inactive
XD7-0 values are driven onto D7-0 pins when XDRD
is active.
X-Bus Data Buffer
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