PD6710 Datasheet, PDF (82/138 Pages) Intel Corporation – ISA-to-PC-Card (PCMCIA) Controllers

PD6710/’22 — ISA-to-PC-Card (PCMCIA) Controllers
10.7.5
External Data (PD6722 only, Socket A, Index 6Fh)
Register Name: External Data
Index: 6Fh only
Bit 7
Bit 6
Bit 5
Extended Index: 0Ah
Bit 4
Bit 3
Bit 2
Register Per: socket
Register Compatibility Type: ext.
Bit 1
Bit 0
External Data
7
External Data
6
External Data
5
External Data
4
External Data External Data External Data External Data
3 or
2 or
1 or
0 or
B_VS2# Input B_VS1# Input A_VS2# Input A_VS1# Input
RW:0
RW:0
RW:0
RW:0
R:0
R:0
R:0
R:0
Bits 7:0 — External Data
This register is updated and accessed according to the setting of bits 3 and 4 of the Socket B
Extension Control 2 register (Index 6Fh, Extended Index 0Bh).
Table 16. Functions of Socket B External Data Register (PD6722 only)
Socket B Extension Control 2
Bit 4: GPSTB Bit 3: GPSTB
on IOW*
on IOR*
Function of Socket B External Data Register
Bits 7:4 — scratchpad
0
0
Bits 3:2 — Socket B VS2# and VS1# levels (PD6722 only)
Bits 1:0 — Socket A VS2# and VS1# levels
0
1
External read port: B_GPSTB is a read buffer enable for external data on
SD[15:8].
External write port: B_GPSTB is a write latch enable for SD[15:8] to get
1
0
latched to an external register. Reads of Socket B External Data register
produce the value written to the latch.
1
1
Reserved
Note:
For software compatibility of external data access accross the PC Card (PCMCIA) controller
product line, the Socket B External Data register should only be used as a read port and not as a
write port. Also for compatibility, only the lower nibble of External Data should be accessed and
the upper nibble should be ignored. For software compatibility with VS1# and VS2# detection
software, when Socket B is used as a read port, socket VS1# and VS2# signals should be connected
to the external read buffer as shown in Figure 15 on page 96.
Refer to “Using GPSTB Pins for External Port Control (PD6722 only)” on page 91 for more
information on the use of the External Data register, and “VS1# and VS2# Voltage Detection” on
page 95 for more information on VS1# and VS2# detection.
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Datasheet