spd6722qcce Intel Corporation, spd6722qcce Datasheet - Page 81

• Manufacturer Part Number: spd6722qcce
• Description: Isa-to-pc-card Pcmcia Controllers
• Manufacturer: Intel Corporation

10.7.4
Datasheet
Register Name: External Data
Index: 2Fh only
External Data
Table 14. Maximum DMA Acknowledge Delay Register Values (Sheet 2 of 2)
Table 15. Functions of Socket A External Data Register
RW:0
Bit 7
7
Note: For software compatibility of external data access accross the PC Card (PCMCIA) controller
External Data
External Data (PD6722 only, Socket A, Index 2Fh)
Bits 7:0 — External Data
This register is updated and accessed according to the setting of bits 3 and 4 of the Socket A
Extension Control 2 register (Index 2Fh, Extended Index 0Bh).
product line, the Socket A External Data register should only be used as a write port and not as a
read port. Also for compatibility, only the lower nibble of External Data should be accessed and
the upper nibble should be ignored.
Refer to
information on the use of the External Data register.
Bit 4: GPSTB
Socket A Extension Control 2
RW:0
Bit 6
on IOW*
Register Value
6
0
0
1
1
“Using GPSTB Pins for External Port Control (PD6722 only)” on page 91
E0h
D0h
B0h
10h
90h
50h
30h
External Data
RW:0
Bit 5
Bit 3: GPSTB
5
on IOR*
0
1
0
1
External Data
(25-MHz internal clock and default Setup timing)
RW:0
Extended Index: 0Ah
Bit 4
Scratchpad
External read port: A_GPSTB is a read buffer enable for external data on
SD[15:8]
External write port: A_GPSTB is a write latch enable for SD[15:8] to get
latched to an external register. Reads of Socket A External Data register
produce the value written to the latch.
Reserved
4
Maximum DMA Acknowledge Delay
ISA-to-PC-Card (PCMCIA) Controllers — PD6710/’22
External Data
13 clocks = 520 ns
14 clocks = 560 ns
15 clocks = 600 ns
16 clocks = 640 ns
17 clocks = 680 ns
18 clocks = 720 ns
19 clocks = 760 ns
Function of Socket A External Data Register
RW:0
Bit 3
3
External Data
RW:0
Bit 2
2
Register Compatibility Type: ext.
External Data
RW:0
Bit 1
1
Register Per: socket
for more
External Data
RW:0
Bit 0
0
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