XRT91L30
24
STS-12/STM-4 OR STS-3/STM-1 SONET/SDH TRANSCEIVER
REV. 1.0.2
TABLE 13: ALTERNATE TRANSMIT PARALLEL DATA INPUT TIMING (STS-12/STM-4 OPERATION)
TABLE 14: ALTERNATE TRANSMIT PARALLEL DATA INPUT TIMING (STS-3/STM-1 OPERATION).
3.5
Transmit Parallel Input to Serial Output (PISO)
The PISO is used to convert 77.76 Mbps or 19.44 Mbps parallel data input to 622.08 Mbps STS-12/STM-1 or
155.52 Mbps STS-3/STM-1 serial data output respectively, which can interface to an optical module. The
PISO bit interleaves parallel data input into a serial bit stream taking the first bit from TXDI7, then the first bit
SYMBOL
PARAMETER
MIN
TYP
MAX
UNITS
tTXPCLK_IO
Transmit Clock Input period
12.86
ns
tTXDI_SU
Transmit data setup time with respect to TXPCLK_IO
2.0
ns
tTXDI_HD
Transmit data hold time with respect to TXPCLK_IO
1.0
ns
SYMBOL
PARAMETER
MIN
TYP
MAX
UNITS
tTXPCLK_IO
Transmit Clock Input period
51.44
ns
tTXDI_SU
Transmit data setup time with respect to TXPCLK_IO
2.0
ns
tTXDI_HD
Transmit data hold time with respect to TXPCLK_IO
1.0
ns
FIGURE 15. SIMPLIFIED BLOCK DIAGRAM OF PISO
b00
b01
b02
b03
b04
b05
b06
b07
bn0
bn1
bn2
bn3
bn4
bn5
bn6
bn7
bn+0
bn+1
bn+2
bn+3
bn+4
bn+5
bn+6
bn+7
b70
b71
b72
b73
b74
b75
b76
b77
8-bit Parallel LVTTL Input Data
TXDI0
TXDI7
TXDIn+
TXDIn
TXOP/N
TXPCLK_IO
77.76 MHz (STS-12/STM-4) or 19.44 MHz (STS-3/STM-1)
622.08 Mbps STS-12/STM-4 or
155.52 Mbps STS-3/STM-1 serial data rate
b40
b50
b60
b70
b20
b30
b47
b57
b67
b77
b37
P
IS
O
time (0)
b27 b17 b07
b10 b00