IBM 3745 Maintenance Information Reference page 535

Error Detection and Reporting
Reporting
DMA/SCTL Errors
The error conditions just described are encoded by the SCTL-DMA card and the
switch card, and reported on 4 x SCTUOMSW error lines which go from the
OMSW card to the FESH card as shown next:
Checkers Checkers
t t
SCll DMSW
FESH
Card Card Card
r
1
3 Error Li nes 4 Error lines
Reporting DMA errors is done by issuing a level 2 interrupt to the CSP. The
nature of the error is set into an LCS/ELCS (refer to "Line Communication
Status (LCS)" on page 4-194 and "Extended Line Communication Status (ELCS)
(Initial Status = 8'11Q') for HSS" on page 4-198 for code description).
When any of the above checkers becomes active:
1. The hardware:
• Stores the corresponding error condition in an error register X'10' and
X'11'.
• Interrupts the CSP
mic~ocode.
2. The CSP microcode
• Stops the transmit and receive operations in process.
• In case of transmit, puts the transmit data line at mark.
• In case of receive, stops the receive command and modem monitoring.
They are reported by the FESH through a level 2 interrupt and then both inter-
face are disabled by the microcode.
The CSP microcode fills the LCS fietd of the PSA status with a status byte
telling the reason for the erro~ (refer to "Line Communication Status (LCS)" on
page 4-194 and "Extended Line Communication Status (ELCS) (Initial
Status =8'110') for HSS" on page 4-198 for code description).
The microcode then raises CCU level 2 interrupt.
Line interfaces are started again by the CSP microcode when the NCP sends
the proper SOLC command. sequence.
6-54
IBM 3745 Maintenance Information Reference (MIR)