Maxim Integrated 78Q8430 Software Driver - Manual (Page 12)

78Q8430 Software Driver Development Guidelines UG_8430_004
STEP 1: Enable multicast filter #1 in the CAM.
Modify CAM rule 0x7D (multicast filter #1 byte [0]) to enable the filter.
• Write 0x7D to the CAR Address field.
• Set the RMR Previous Hit Mask field to 0x7F.
3.4.3 Start Local PAUSE Timer
Use the following procedure to start the local PAUSE timer immediately:
STEP 1: Write to PDCR to activate the local PAUSE condition.
Set the PDCR Start bit to start the PAUSE timer. Set the desired local PAUSE duration in the PDCR
Pause field at the same time.
3.5 HNR Frame Transmission
When the host fails to acknowledge a Wake-On-LAN (WOL) event before the specified timer expires, the
78Q8430 can be configured to automatically transmit an HNR frame. The device may also be
commanded to transmit an HNR frame immediately. This section describes the procedures for HNR
frame transmission.
3.5.1 Specify HNR Frame
Use the following procedure to write the desired HNR frame to QUE 5:
STEP 1: Write to QUE 5 PCWR.
Writing to this register sets the ID and transmission options for the frame and initializes the write logic
for QUE 5. The driver should assign a unique ID number to each transmitted frame. When the write
logic is initialized, it triggers an under-run interrupt for QUE 5 if the previous frame has not been
completed. This has the effect of aborting the previous frame.
STEP 2: Write to QUE 5 PSZR.
Writing to PSZR indicates to the QUE 5 write logic how many bytes to expect. For example, if the
part is operating in 32-bit bus mode and the byte count is not an even multiple of four, the write logic
uses the size value to determine how many bytes in the last write are valid. If the host attempts to
write an extra word past the end of the programmed size, an overrun interrupt results.
STEP 3: Write the frame data to QUE 5 TDR.
Each successive write to TDR adds the data to QUE 5.
STEP 4: Read the transmit status from TPSR.
Reading TPSR reads status words from the top of a 128 word deep FIFO. One status word is added
to the FIFO for each transmitted frame. If the software does not read the status words for transmitted
frames from the FIFO, it eventually fills to capacity at which time any new status words are dropped
while the FIFO retains the oldest ones.
3.5.2 HNR Automatic Transmission
The Host Not Responding (HNR) frame is sent automatically in the event that the host fails to respond to
a remote request for it to wake. The HNR Timer is used for this purpose. After the classification identifies
a wake event, the HNR Timer is started. If the host does not respond to the wake event by clearing the
Power Management Event (PME) bit in the Power Management Control and Status Register (PMCSR)
before the HNR Timer expires, the HNR frame is automatically transmitted.
The duration of the HNR Timer should be selected with the speed of the host processor and the interrupt
latency of the system in mind such that the host has adequate time in the worst case to receive and
process the wake interrupt and clear the PME bit.
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