AT&T 3B2 Off-Line Diagnostic Manual page 91

- - - - - - - - - - - - - - - - - - - - - Version 2 Hardware System Board Diagnostics
Test Number:
Function:
Procedure:
9
This test confirms that the DMAC can perform a Direct Memory Access (DMA)
operation.
The test procedure is as follows:
1. The B-side Dual Universal Asynchronous Receiver/Transmitter
(DUART) is initialized to local loop around mode.
2. The DMAC is initialized for DMA operation through the DUART, and
the four-character string "TEST" is transmitted.
3. The DMA job is requested, and it is waited on for completion.
4. The B side of the DUART is checked for the First-In-First-Out (FIFO
Full) bit to be set in the DUART Status register. The reception of the
character string "TEST" is confirmed.
Hardware Tested: The 9517 DMAC is tested.
Data Returned: The failing test number (last number displayed on the system console before
failure) is tested.
Notes: Pattern OxfOxx is returned, where xx equals the failing contents of the DUART
Status register or 1 through 4 are returned, where 1 through 4 represents the
number of failing characters in the string" TEST."
SYSTEM BOARD DIAGNOSTICS 3-51