
Smart Card Controller Programming Model
230
September 2005
SCPS110
13.3 Command Register
The command register provides control over the Smart Card controller interface to the PCI bus. All bit functions
adhere to the definitions in the PCI Local Bus Specification, as seen in the following bit descriptions. The
SERR_EN and PERR_EN enable bits in this register are internally wired-OR between other functions, and
these control bits appear separately according to their software function. See Table 132 for a complete
description of the register contents.
Function 4 register offset: 04h
Register type:
Read/Write, Read-only
Default value:
0000h
BIT NUMBER
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RESET STATE
0
Table 132. Command Register Description
BIT
FIELD NAME
TYPE
DESCRIPTION
1511
RSVD
R
Reserved. Bits 1511 return 00000b when read.
10
INT_DIS
RW
INTx disable. When set to 1b, this bit disables the function from asserting interrupts on the INTx signals.
0 = INTx assertion is enabled (default)
1 = INTx assertion is disabled
9
FBB_EN
R
Fast back-to-back enable. The Smart Card interface does not generate fast back-to-back transactions;
therefore, bit 9 returns 0b when read.
8
SERR_EN
RW
System error (SERR) enable. Bit 8 controls the enable for the SERR driver on the PCI interface. SERR
can be asserted after detecting an address parity error on the PCI bus. Both bits 8 and 6 (PERR_EN)
must be set for this function to report address parity errors.
0 = Disable SERR output driver (default)
1 = Enable SERR output driver
7
RSVD
R
Reserved. Bit 7 returns 0b when read.
6
PERR_EN
RW
Parity error response enable. Bit 6 controls this function response to parity errors through PERR. Data
parity errors are indicated by asserting PERR, whereas address parity errors are indicated by asserting
SERR.
0 = This function ignores detected parity error (default)
1 = This function responds to detected parity errors
5
VGA_EN
R
VGA palette snoop enable. The Smart Card interface does not feature VGA palette snooping;
therefore, bit 5 returns 0b when read.
4
MWI_EN
R
Memory write and invalidate enable. The Smart Card controller does not generate memory write
invalidate transactions; therefore, bit 4 returns 0b when read.
3
SPECIAL
R
Special cycle enable. The Smart Card interface does not respond to special cycle transactions;
therefore, bit 3 returns 0b when read.
2
MAST_EN
R
Bus master enable. This function is target only.
1
MEM_EN
RW
Memory space enable. This bit controls memory access.
0 = Disables this function from responding to memory space accesses (default)
1 = Enables this function to respond to memory space accesses
0
IO_EN
R
I/O space enable. The Smart Card interface does not implement any I/O-mapped functionality;
therefore, bit 0 returns 0b when read.