82801BA Datasheet, PDF (239/498 Pages) Intel Corporation – Intel 82801BA I/O Controller Hub 2 (ICH2) and Intel 82801BAM I/O Controller Hub 2 Mobile

LAN Controller Registers (B1:D8:F0)
Bit
Description
Command Unit Command (CUC). Valid values are listed below. All other values are Reserved.
0000 = NOP: Does not affect the current state of the unit.
0001 = CU Start: Start execution of the first command on the CBL. A pointer to the first CB of the
CBL should be placed in the SCB General Pointer before issuing this command. The CU
Start command should only be issued when the CU is in the Idle or Suspended states
(never when the CU is in the active state), and all of the previously issued Command
Blocks have been processed and completed by the CU. Sometimes it is only possible to
determine that all Command Blocks are completed by checking that the Complete bit is set
in all previously issued Command Blocks.
0010 = CU Resume: Resume operation of the Command unit by executing the next command.
This command will be ignored if the CU is idle.
0011 = CU HPQ Start: Start execution of the first command on the high priority CBL. A pointer to
the first CB of the HPQ CBL should be placed in the SCB General POinter before issuing
this command.
0100 = Load Dump Counters Address: Tells the device where to write dump data when using the
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Dump Statistical Counters or Dump and Reset Statistical Counters commands. This
command must be executed at least once before any usage of the Dump Statistical
Counters or Dump and Reset Statistical Counters commands. The address of the dump
area must be placed in the General Pointer register.
0101 = Dump Statistical Counters: Tells the device to dump its statistical counters to the area
designated by the Load Dump Counters Address command.
0110 = Load CU Base: The device’s internal CU Base Register is loaded with the value in the
CSB General Pointer.
0111 = Dump and Reset Statistical Counters: Tells the device to dump its statistical counters to
the area designated by the Load Dump Counters Address command, and then to clear
these counters.
1010 = CU Static Resume: Resume operation of the Command unit by executing the next
command. This command will be ignored if the CU is idle. This command should be used
only when the CU is in the Suspended state and has no pending CU Resume commands.
1011 = CU HPQ Resume: Resume execution of the first command on the HPQ CBL. this
command will be ignored if the HPQ was never started.
3 Reserved.
Receive Unit Command (RUC). Valid values are:
000 = NOP: Does not affect the current state of the unit.
001 = RU Start: Enables the receive unit. The pointer to the RFA must be placed in the SCB
General POinter before using this command. The device pre-fetches the first RFD and the
first RBD (if in flexible mode) in preparation to receive incoming frames that pass its address
filtering.
010 = RU Resume: Resume frame reception (only when in suspended state).
011 = RCV DMA Redirect: Resume the RCV DMA when configured to "Direct DMA Mode." The
buffers are indicated by an RBD chain which is pointed to by an offset stored in the General
Pointer Register (this offset will be added to the RU Base).
2:0 _{100 = RU Abort: Abort RU receive operation immediately.}
101 = Load Header Data Size (HDS): This value defines the size of the Header portion of the RFDs
or Receive buffers. The HDS value is defined by the lower 14 bits of the SCB General Pointer,
so bits 31:15 should always be set to zeros when using this command. Once a Load HDS
command is issued, the device expects only to find Header RFDs, or be used in "RCV Direct
DMA mode" until it is reset. Note that the value of HDS should be an even, non-zero number.
110 = Load RU Base: The device’s internal RU Base Register is loaded with the value in the SCB
General Pointer.
111 = RBD Resume: Resume frame reception into the RFA. This command should only be used
when the RU is already in the "No Resources due to no RBDs" state or the "Suspended with
no more RBDs" state.
82801BA ICH2 and 82801BAM ICH2-M Datasheet
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