
PC Card Controller Programming Model
104
September 2005
SCPS110
4.48 Serial Bus Slave Address Register
The serial bus slave address register is for programmable serial bus byte read and write transactions. To write
a byte, the serial bus data register must be programmed with the data, the serial bus index register must be
programmed with the byte address, and this register must be programmed with both the 7-bit slave address
and the read/write indicator bit.
On byte reads, the byte address is programmed into the serial bus index register, this register must be
programmed with both the 7-bit slave address and the read/write indicator bit, and bit 5 (REQBUSY) in the
serial bus control and status register (see Section 4.49) must be polled until clear. Then the contents of the
serial bus data register are valid read data from the serial bus interface. See Table 424 for a complete
description of the register contents.
PCI register offset:
B2h (function 0)
Register type:
Read/Write
Default value:
00h
BIT NUMBER
7
6
5
4
3
2
1
0
RESET STATE
0
Table 424. Serial Bus Slave Address Register Description
BIT
SIGNAL
TYPE
FUNCTION
71
SLAVADDR
RW
Serial bus slave address. This bit field represents the slave address of a read or write transaction on the
serial interface.
0
RWCMD
RW
Read/write command. Bit 0 indicates the read/write command bit presented to the serial bus on byte read
and write accesses.
0 = A byte write access is requested to the serial bus interface
1 = A byte read access is requested to the serial bus interface
These bits are cleared only by the assertion of GRST.
4.49 Serial Bus Control/Status Register
The serial bus control and status register communicates serial bus status information and selects the quick
command protocol. Bit 5 (REQBUSY) in this register must be polled during serial bus byte reads to indicate
when data is valid in the serial bus data register. See Table 425 for a complete description of the register
contents.
PCI register offset:
B3h (function 0)
Register type:
Read-only, Read/Write, Read/Clear
Default value:
00h
BIT NUMBER
7
6
5
4
3
2
1
0
RESET STATE
0