ISA-to-PC-Card (PCMCIA) Controllers — PD6710/’22
14.0
VS1# and VS2# Voltage Detection
The PD6722 provides support for VS1# and VS2# voltage sense for environments where special
low-voltage keyed PC Card sockets are to be used. With a low-voltage keyed socket, it is necessary
to determine the operating voltage range of a card before applying power to it. The PD6722
supports reading of the levels on a socket’s VS1# and VS2# pins through a uniform extended
register programming model using Socket B extended register 0Ah. The programming model is as
follows:
Register Name:
External Data
Index:
6Fh
Bit 7
External Data
7
RW:0
Bit 6
External Data
6
RW:0
Bit 5
External Data
5
RW:0
Extended Index:
0Ah
Bit 4
External Data
4
RW:0
Bit 3
B_VS2 Input
R:0
Bit 2
B_VS1 Input
R:0
Register Per:
socket
Register Compatibility Type:
ext.
Bit 1
A_VS2 Input
R:0
Bit 0
A_VS1 Input
R:0
For voltage detection on the PD6710, refer to the 5V_DET pin.
On the PD6722, the B_GPSTB pin is programmed as a general-purpose read strobe. The VS1# and
VS2# pins from the A and B sockets are connected to the external half of a ’244 buffer as follows
(which allows Socket A VS1 and VS2 to appear as bits 0 and 1, and Socket B VS1 and VS2 to
appear as bits 2 and 3):
Datasheet
95
INTEL [ INTEL CORPORATION ]
