82434LX Datasheet, PDF (44/191 Pages) Intel Corporation – PCI, CACHE AND MEMORY CONTROLLER PCMC

82434LX 82434NX
3 2 9 BASEC BASE CLASS CODE REGISTER
Address Offset
Default Value
Attribute
Size
0Bh
06h
Read Only
8 bits
This register defines the PCMC as a bridge device
Bits
Description
7 0 BASE CLASS CODE (BCCD) The value in this register is 06h defining the PCMC as bridge device
3 2 10 MLT MASTER LATENCY TIMER REGISTER
Address Offset
Default Value
Attribute
Size
0Dh
20h
Read Write
8 bits
MLT is an 8-bit register that controls the amount of time the PCMC as a bus master can burst data on the PCI
Bus MLT is used when the PCMC becomes the PCI Bus master and is cleared and suspended when the
PCMC is not asserting FRAME When the PCMC asserts FRAME the counter is enabled and begins
counting If the PCMC finishes its transaction before the count expires the MLT count is ignored If the count
expires before the transaction completes the PCMC initiates a transaction termination as soon as its GNT is
removed The number of clocks programmed in the MLT represents the guaranteed time slice (measured in
PCI clocks) allotted to the PCMC after which it must surrender the bus as soon as its GNT is taken away
The number of clocks in the Master Latency Timer is the count value field multiplied by 16
Bits
Description
7 4 MASTER LATENCY TIMER COUNT VALUE If GNT is negated after the burst cycle is initiated the
PCMC limits the duration of the burst cycle to the number of PCI Bus clocks specified by this field
multiplied by 16
3 0 RESERVED
3 2 11 BIST BIST REGISTER
Address Offset
Default Value
Attribute
Size
0Fh
0h
Read Only
8 bits
The BIST function is not supported by the PCMC Writes to this register have no affect
Bits Attribute
Description
7
RO BIST SUPPORTED This read only bit is always set to 0 disabling the BIST function
Writes to this bit position have no affect
6
RW START BIST This function is not supported and writes have no affect
54
RESERVED
30
RO COMPLETION CODE This read only field always returns 0 when read and writes have
no affect
44