Kontron 886LCD-M/ATX User Manual page 30

KTD-00474-U
Signal Description – AGP Connector:
Signal
Address
Pipelined Read: This signal is asserted by the AGP master to indicate a full width address is to
PIPE#
be enqueued on by the target using the AD bus. One address is placed in the AGP request
queue on each rising clock edge while PIPE# is asserted. When PIPE# is deasserted no new
requests are queued across the AD bus.
During SBA Operation: This signal is not used if SBA (Side Band Addressing) is selected.
During FRAME# Operation: This signal is not used during AGP FRAME# operation.
PIPE# is a sustained tri-state signal from masters (graphics controller), and is an input to the
GMCH
Side-band Address: These signals are used by the AGP master (graphics controller) to pass
ADD_ID[7:0]
address and command to the GMCH. The SBA bus and AD bus operate independently. That is,
transactions can proceed on the SBA bus and the AD bus simultaneously.
During PIPE# Operation: These signals are not used during PIPE# operation.
During FRAME# Operation: These signals are not used during AGP FRAME#
operation.
NOTE: When sideband addressing is disabled, these signals are isolated (no external/internal
pull-ups are required).
Flow control
Read Buffer Full: Read buffer full indicates if the master is ready to accept previously requested
RBF#
low priority read data. When RBF# is asserted the GMCH is not allowed to initiate the return low
priority read data. That is, the GMCH can finish returning the data for the request currently being
serviced. RBF# is only sampled at the beginning of a cycle. If the AGP master is always ready to
accept return read data then it is not required to implement this signal.
During FRAME# Operation: This signal is not used during AGP FRAME# operation.
Write-Buffer Full: indicates if the master is ready to accept Fast Write data from the GMCH.
WBF#
When WBF# is asserted the GMCH is not allowed to drive Fast Write data to the AGP master.
WBF# is only sampled at the beginning of a cycle. If the AGP master is always ready to accept
fast write data then it is not required to implement this signal.
During FRAME# Operation: This signal is not used during AGP FRAME# operation.
AGP Status
Status: Provides information from the arbiter to an AGP Master on what it may do. ST[2:0] only
ST[2:0]
have meaning to the master when its GNT# is asserted. When GNT# is deasserted these signals
have no meaning and must be ignored.
ST[2:0 Meaning
000 Previously requested low priority read data is being returned to the master
001 Previously requested high priority read data is being returned to the master
010 The master is to provide low priority write data for a previously queued write command
011 The master is to provide high priority write data for a previously queued write command
100 Reserved
101 Reserved
110 Reserved
111 The master has been given permission to start a bus transaction. The master may queue
AGP requests by asserting PIPE# or start a PCI transaction by asserting FRAME#.
AGP Strobes
Address/Data Bus Strobe-0: provides timing for 2x and 4x data on AD[15:0] and C/BE[1:0]#
ADSTB[0]
signals. The agent that is providing the data will drive this signal.
Address/Data Bus Strobe-0 Complement: With AD STB0, forms a differential strobe pair that
ADSTB#[0]
provides timing information for the AD[15:0] and C/BE[1:0]# signals. The agent that is providing
the data will drive this signal.
Address/Data Bus Strobe-1: Provides timing for 2x and 4x data on AD[31:16] and C/BE[3:2]#
ADSTB[1]
signals. The agent that is providing the data will drive this signal.
Address/Data Bus Strobe-1 Complement: With AD STB1, forms a differential strobe pair that
ADSTB#[1]
provides timing information for the AD[15:0] and C/BE[1:0]# signals in 4X mode. The agent that
is providing the data will drive this signal.
Sideband Strobe: Provides timing for 2x and 4x data on the SBA[7:0] bus. It is driven by the
SBSTB
AGP master after the system has been configured for 2x or 4x sideband address mode.
Sideband Strobe Complement: The differential complement to the SB_STB signal. It is used to
SBSTB#
provide timing 4x mode.
886LCD-M Family
Public User Manual Date: 2010-06-22
Description
Page 30 of 81
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