EAC Card
3. Issue a Start Transmit command to the EAC. The EAC will enter in a transmit
mode and then start processing the transmit buffer provided in the control word.
EAC buffer processing works as follows:
If the first transmit buffer address is not zero and the NCP buffer count is
not zero, then all data in the chain of NCP buffers is transmitted, until an
NCP buffer link pointer of zero is detected.
If the first transmit buffer address is not zero and the NCP buffer count is
zero, then the first buffer is skipped. Data in all buffers chained to the first
is transmitted, until an NCP buffer link pointer of zero is detected.
For buffers subsequent to the first, the offset and count are taken from the
buffer prefix and a prefix length of x'08' is used.
4. Build the ending status and transfer it to the CCU.
5. Set a CCU level 2 interrupt request.
Typical Ending Statuses
┌──────┬───────┬───────┬────────────────────────┐
│ SCF │ SES │ LCS │ Meaning
│
├──────┼───────┼───────┼────────────────────────┤
│ 46
│
ðð
│
ðð
│
Transmit started
│
│ ðð
│
ðð
│
D2
│
Command rejected
│
│ ðð
│ ðð
│ Seeñ │ Internal box error
│
│ 1ð
│
ðð
│
F4
│
Ethernet error (LCAR) │
│ C4
│
ðð
│
ðð
│
Halt executed
│
└──────┴───────┴───────┴────────────────────────┘
ñ
= Refer to “Line Communication Status (LCS)” on page 12-30 for details.
Receive
The Receive Command is used to pass the address of the first buffer in a receive
data buffer chain to the CSP and to place the CSP in receive mode.
CSP Processing
1. Get the parameters from the CCU.
2. Prepare a receive control word for the EAC containing:
The buffer count from the PSA
The buffer offset from the PSA
The first receive buffer address from the PSA.
Note: A Buffer Prefix Length of x'08' is used by the ESS.
3. Issue a Start Receive command to the EAC. The EAC will enter in receive
mode where it is allowed to start receiving packets from the line.
4. Start a timer to wait for any received packets. This timer value will be internal
to the microcode, but must be less that the NCP backup timer value used to
wait for any command status.
5. If any statistical counters have overflowed, bit 7 of the SCF status will be set
indicating this fact.
6. When an end of message interrupt is received from the EAC or the receive
timer expires, build an ending status and transfer it to the CCU.
7. Set a CCU level 2 interrupt request.
12-22
IBM 3745 Models 130, 150, 160, 170, and 17A: Hardware Maintenance Reference
Содержание 3745 Series
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Страница 21: ...3745 Models 130 150 160 and 170 Data Flow Chapter 1 General Information 1 3 ...
Страница 149: ...For RACs 241 to 244 ERR bits Data received from the adapter Chapter 3 Buses 3 57 ...
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Страница 169: ...Chapter 4 Transmission Subsystem TSS 4 17 ...
Страница 255: ...The HPTSS in 3745 Models 130 150 160 and 170 Data Flow Chapter 5 High Performance Transmission Subsystem HPTSS 5 3 ...
Страница 303: ...Figure 6 8 Ring to Ring via Bridge Example 2 Typical Multi Floor Wiring Chapter 6 The Token Ring Subsystem 6 9 ...
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Страница 625: ...The ESS in 3745 Models 130 150 160 and 170 Data Flow Chapter 12 Ethernet Subsystem ESS 12 3 ...
Страница 668: ...Problem Determination Aid 12 46 IBM 3745 Models 130 150 160 170 and 17A Hardware Maintenance Reference ...
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Страница 712: ...IBM Part Number 03F5010 Printed in Denmark by IBM Danmark A S ð3F5ð1ð SY33 2ð66 4 ...