STANDARD PRODUCT
PM4328 TECT3
DATASHEET
PMC-2011596
ISSUE 1
HIGH DENSITY T1/E1 FRAMER
AND M13 MULTIPLEXER
13.2 DS3 System Side Interface Timing
Figure 52: Framer Mode DS3 Transmit Input Stream
TICLK or RCLK
INFO 82 INFO 83 INFO 84
INFO 82 INFO 83 INFO 84
TDATI
X2
INFO 82 INFO 83 INFO 84
INFO 1 INFO 2
INFO 1 INFO 2 INFO 3
X1
F4
TFPI/TMFPI
TFPO/TMFPO
Figure 53: Framer Mode DS3 Transmit Input Stream With TGAPCLK
TGAPCLK
TDATI
INFO 1
INFO 2 INFO 3
INFO 4
INFO 83 INFO 84
INFO 1
INFO 83 INFO 84
INFO 1
INFO 2 INFO 3
INFO 81 INFO 82 INFO 83
The Framer Mode DS3 Transmit Input Stream diagram (Figure 52) shows the
expected format of the inputs TDATI and TFPI/TMFPI along with TICLK and the
output TFPO/TMFPO when the OPMODE[1:0] bits are set to “DS3 Framer Only
mode” in the Global Configuration register. If the TXMFPI bit in the DS3 Master
Unchannelized Interface Options register is logic 0, then TFPI is valid, and the
TECT3 will expect TFPI to pulse for every DS3 overhead bit with alignment to
TDATI. If the TXMFPI register bit is logic 1, then TMFPI is valid, and the TECT3
will expect TMFPI to pulse once every DS3 M-frame with alignment to TDATI. If
the TXMFPO bit in the DS3 Master Unchannelized Interface Options register is
logic 0, then TFPO is valid, and the TECT3 will pulse TFPO once every 85 TICLK
cycles, providing upstream equipment with a reference DS3 overhead pulse. If
the TXMFPO register bit is logic 1, then TMFPO is valid and the TECT3 will pulse
TMFPO once every 4760 TICLK cycles, providing upstream equipment with a
reference M-frame pulse. The alignment of TFPO or TMFPO is arbitrary. There
is no set relationship between TFPO/TMFPO and TFPI/TMFPI. When the DS3
interface is loop timed by setting the LOOPT bit in the DS3 Master Data Source
register, RCLK replaces TICLK as the transmit timing reference and all timing is
relative to RCLK.
The TGAPCLK output is available in place of TFPO/TMFPO when the TXGAPEN
bit in the DS3 Master Unchannelized Interface Options register is set to logic 1,
as in Figure 53. TGAPCLK remains high during the overhead bit positions.
TDATI is sampled on the active edge of TGAPCLK when TXGAPEN is set to
logic 1 and on the active edge of TICLK when TXGAPEN is set to logic 0. The
TDATIFALL bit in the DS3 Master Unchannelized Interface Options register
selects the active edge of TICLK or TGAPCLK for sampling TDATI.
PROPRIETARY AND CONFIDENTIAL
185
PMC [ PMC-SIERRA, INC ]
