SCD240110QCM Intel, SCD240110QCM Datasheet - Page 50

• Manufacturer Part Number: SCD240110QCM
• Manufacturer: Intel

Specifications of SCD240110QCM

• Operating Supply Voltage (max): 7V
• Operating Temp Range: 0C to 70C
• Operating Temperature Classification: Commercial
• Mounting: Surface Mount
• Pin Count: 100
• Lead Free Status / Rohs Status: Not Compliant

CD2401 — Multi-Protocol Communications Controller
50
Example 2
Transmit out of channel 0, and chain three buffers into one frame. The frame is 240 bytes long, and
the maximum buffer size is 100.
10. The CD2401 continues transmission of the current frame, but now transmission is from buffer
11. After the CD2401 has completed transmission of the second link out of buffer A, the CD2401
12. The CD2401 optionally interrupts the host with the EOF bit cleared and the EOB bit set
13. By this time, the host has set up a new buffer for buffer B. The EOF bit (BTBSTS[6]) is set to
14. The CD2401 then transmits buffer B in the same manner as above. As before, the CD2401
7. The CD2401 optionally interrupts the host, with EOF and EOB (TISR[6:5]) both set to
1. The host checks the Ntbuf bit (DMABSTS[3]) for channel 0 to determine which buffer is next.
2. The host sets up the buffer data, the starting address — BTBADR, and the buffer byte count —
3. The host sets up the BTBSTS register. The EOF bit is cleared to indicate that this buffer is the
4. At this point, the host has enough time to transmit 100 bytes to set up the next buffer link. If
5. The CD2401 starts transmitting buffer B from channel 0. When this is started, the Ntbuf bit is
6. At the end of transmission of this buffer, the CD2401 does not add any CRCs or end-of-frame
7. After the CD2401 has completed transmission of the first link out of buffer B, the CD2401 sets
8. The CD2401 optionally interrupts the host with EOF clear and EOB set (TISR[6:5]) to
9. The CD2401 now sees from the ATBSTS register that it has ownership of buffer A for
indicate that the transmission is complete, and there was no chaining.
In this example, Ntbuf is set to ‘1’ indicating that buffer B is used next.
BTBCNT, for the first ‘link’ of the chain to be transmitted. For this example, BTBCNT is set
to 100.
first link in a chain. The 2401own bit is set to give ownership to the CD2401. By setting
2401own, the host commands the CD2401 to start transmission. Thus, everything must be
ready (starting address, buffer, data count) prior to setting 2401own.
the host fails to do this in time, there is a transmitter underrun, and the frame is aborted in
HDLC or bisynchronous.
cleared to ‘0’ to indicate that buffer A is next. This helps the host keep track of which buffer is
next. As transmission progresses, the current buffer pointer (TCBADR) is updated by the
CD2401. During or prior to this, the host has readied buffer A. For buffer A, the EOF bit
(ATBSTS[6]) is cleared by the host, indicating that the buffer is not the end of the chain.
delimiters because there is more data for the current frame.
the EOB bit and clears the 2401own bit (BTBSTS[0]). This notifies the host that the
transmission is complete, and returns ownership of the buffer back to the host.
indicate that the transmission is complete, and that there was chaining.
transmission of the next ‘link’. It also sees that the EOF is clear so that this link is not the last
link in the transmitted chain.
A. This is the second link, and is 100 bytes long. During this time, the host must set up a new
buffer B for the third and final link. The BTBCNT for the last link is set to 40 bytes.
sets the EOB bit and clears the 2401own bit (ATBSTS[0]). This notifies the host that the
transmission is complete, and returns ownership of the buffer back to the host. As with the first
link, the CD2401 does not add CRCs or ending frame delimiters to this link.
(TISR[6:5]) to indicate that the transmission is complete, and there was chaining.
indicate that this is the last link in the chain.
transmits the number of bytes indicated in the BTBCNT, which is 40 for the third segment.
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