Maxim Integrated DS33R11 - Manual (Page 111)

DS33R11 Ethernet Mapper with Integrated T1/E1/J1 Transceiver
111 of 344
10.26 Payload Error-Insertion Function (T1 Mode Only)
An error-insertion function is available in the transceiver and is used to create errors in the payload portion of the
T1 frame in the transmit path. This function is only available in T1 mode. Errors can be inserted over the entire
frame or the user can select which channels are to be corrupted. Errors are created by inverting the last bit in the
count sequence. For example, if the error rate 1 in 16 is selected, the 16th bit is inverted. F-bits are excluded from
the count and are never corrupted. Error rate changes occur on frame boundaries. Error-insertion options include
continuous and absolute number with both options supporting selectable insertion rates.
Table 10-14. Transmit Error-Insertion Setup Sequence
STEP ACTION
1 Enter desired error rate in the TR.ERC register. Note: If TR.ER3 through TR.ER0 = 0,
no errors are generated even if the constant error-insertion feature is enabled.
2A
or
2B
For constant error insertion, set CE = 1 (TR.ERC.4).
For a defined number of errors:
– Set CE = 0 (TR.ERC.4)
– Load TR.NOE1 and TR.NOE2 with the number of errors to be inserted
– Toggle WNOE (TR.ERC.7) from 0 to 1 to begin error insertion
10.26.1 Number-of-Errors Registers
The number-of-error registers determine how many errors are generated. Up to 1023 errors can be generated. The
host loads the number of errors to be generated into the TR.NOE1 and TR.NOE2 registers. The host can also
update the number of errors to be created by first loading the prescribed value into the TR.NOE registers and then
toggling the WNOE bit in the error-rate control registers.
Table 10-15. Error Insertion Examples
VALUE WRITE READ
000h Do not create any errors No errors left to be inserted
001h Create a single error One error left to be inserted
002h Create two errors Two errors left to be inserted
3FFh Create 1023 errors 1023 errors left to be inserted