Smart Machine Smart Decision
SIM5360_Hardware Design_V1.01
2013-11-22
42
3.11
PCM Interface
SIM5360 provides hardware PCM interface for external codec. The PCM interface enables
communication with an external codec to support hands-free applications. SIM5360 PCM interface can be
used in two modes: the default mode is auxiliary PCM (8 KHz long sync mode at 128 KHz PCM CLK);
the other mode is primary PCM (8 KHz short sync mode at 2048 KHz PCM CLK). In short-sync
(primary PCM) mode, SIM5360 can be a master or a slave. In long-sync (auxiliary PCM) mode, SIM5360
is always a master. SIM5360 also supports 3 kinds of coding formats: 8 bits (
υ
-law or A-law) and 16 bits
(linear).
Note: PCM interface is multiplexed from GPIO (default setting). The AT command “AT+CPCM” is used to switch
between PCM and GPIO functions. Please refer to document [22] and document [1] for details.
3.11.1
Pin Description
Table 24: Electronic characteristic
Pin name
DC Characteristics
Min
Typ
Max
PCM_CLK
-0.3
1.8
2.1
PCM_SYNC
-0.3
1.8
2.1
PCM_DOUT
-0.3
1.8
2.1
PCM_DIN
-0.3
1.8
2.1
Table 25: Pin description
Pins
Pin No.
AUX_PCM
functionality
Primary PCM
functionality
Description
PCM_DIN/GPIO0
74
AUX_PCM_DIN
PCM_DIN
PCM data input
PCM_SYNC/GPIO2 75
AUX_PCM_SYNC
PCM_SYNC
PCM data synchrony
PCM_DOUT/GPIO5
73
AUX_PCM_DOUT
PCM_DOUT
PCM data output
PCM_CLK/GPIO3
76
AUX_PCM_CLK
PCM_CLK
PCM data clock
3.11.2
Signal Description
The default PCM interface in SIM5360 is the auxiliary PCM interface. The data changes on the high level
of PCM_CLK and is sampled at the falling edge of PCM_CLK in one period. Primary PCM is disabled
after every power-on or every reset event. So user must use AT command to enable the primary PCM