Freescale Semiconductor MCF5480 - Manual (Page 800)

MCF548x Reference Manual, Rev. 3
26-38 Freescale Semiconductor
Figure 26-30. Waveform of Modem8 Mode
The transmitter starts to transmit the first bit at the rising edge of the PSCFSYNC or one clock after the
rising edge of the PSCFSYNC, according to the value in the DTS1 bit in the control register PSCSICR.
The SHDIR bit in the PSCSICR controls the order whether the LSB or the MSB is output first. The width
of the frame sync pulse makes no difference.
Similarly the receiver starts to receive a sample at the rising edge of the PSCFSYNC or one clock after the
rising edge.
The PSCFSYNC is sampled at the negative edge of the bit clock.
26.4.4 Modem16 Mode
Figure 26-31 shows an example of the waveform in 16-bit modem mode.
PSCBCLK
D7 D4 D3 D6 D5 D2 D1 D0
PSCFSYNC
PSCnTXD
D7 D4 D3 D6 D5 D2 D1 D0 PSCnRXD
DTS1 = 0 & SHDIR = 0
PSCBCLK
D0 D3 D4 D1 D2 D5 D6 D7
PSCFSYNC
PSCnTXD
D0 D3 D4 D1 D2 D5 D6 D7 PSCnRXD
DTS1 = 0 & SHDIR = 1
PSCBCLK
D7 D4 D3 D6 D5 D2 D1 D0
PSCFSYNC
PSCnTXD
D7 D4 D3 D6 D5 D2 D1 D0 PSCnRXD
DTS1 = 1 & SHDIR = 0
PSCBCLK
D0 D3 D4 D1 D2 D5 D6 D7
PSCFSYNC
PSCnTXD
D0 D3 D4 D1 D2 D5 D6 D7 PSCnRXD
DTS1 = 1 & SHDIR = 1