Product Info

LTE Module Series
EG25-G Mini PCIe Hardware Design
EG25-G_Mini_PCIe_Hardware_Design 24 / 48
In primary mode, the data is sampled on the falling edge of the PCM_CLK and transmitted on the rising
edge. The PCM_SYNC falling edge represents the MSB. In this mode, PCM_CLK supports 128KHz,
256KHz, 512KHz, 1024KHz and 2048KHz for different speed codecs. The following figure shows the
timing relationship in primary mode with 8KHz PCM_SYNC and 2048KHz PCM_CLK.
PCM_CLK
PCM_SYNC
PCM_DOUT
MSB
LSB
MSB
125us
1 2 256255
PCM_DIN
MSB
LSBMSB
Figure 7: Timing in Primary Mode
In auxiliary mode, the data is sampled on the falling edge of the PCM_CLK and transmitted on the rising
edge; while the PCM_SYNC rising edge represents the MSB. In this mode, PCM interface operates with a
128KHz PCM_CLK and an 8KHz, 50% duty cycle PCM_SYNC only. The following figure shows the timing
relationship in auxiliary mode with 8KHz PCM_SYNC and 128KHz PCM_CLK.
PCM_CLK
PCM_SYNC
PCM_DOUT
MSB
LSB
PCM_DIN
125us
MSB
1 2 1615
LSB
Figure 8: Timing in Auxiliary Mode