PD6710 Datasheet, PDF (95/138 Pages) Intel Corporation – ISA-to-PC-Card (PCMCIA) Controllers

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
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 External Data External Data External Data
7
6
5
4
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
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