Internal Audio Connections; 4-Wire Pcm Serial Interface - Nokia NSB-5 Series Technical Documentation Manual

PAMS Technical Documentation
External accessory notices powered–up phone by detecting voltage in XMIC line. In
Table 9 there is a truth table for detection signals.
Table 9: HookDet/HeadDet Detection Truth Table
Accessory connected
No accessory connected
Headset HDC-9 with a button
switch pressed
Headset HDC-9 with a button
switch released
Handsfree (HFU-1)

Internal Audio Connections

The speech coding functions are performed by the DSP in the MAD2 and the coded
speech blocks are transferred to the COBBA–GJP for digital to analog conversion, down
link direction. In the up link direction the PCM coded speech blocks are read from the
COBBA–GJP by the DSP.
There are two separate interfaces between MAD2 and COBBA–GJP: a parallel bus and a
serial bus. The parallel bus has 12 data bits, 4 address bits, read and write strobes, and a
data available strobe. The parallel interface is used to transfer all the COBBA–GJP control
information (both the RFI part and the audio part) and the transmit and receive samples.
The serial interface between MAD2 and COBBA–GJP includes transmit and receive data,
clock and frame synchronization signals. It is used to transfer the PCM samples. The
frame synchronization frequency is 8 kHz which indicates the rate of the PCM samples
and the clock frequency is 1 MHz. COBBA is generating both clocks.
4–wire PCM Serial Interface
The interface consists of following signals: a PCM codec master clock (PCMDClk), a
frame synchronization signal to DSP (PCMSClk), a codec transmit data line (PCMTX), and
a codec receive data line (PCMRX). The COBBA–GJP generates the PCMDClk clock, which
is supplied to DSP SIO. The COBBA–GJP also generates the PCMSClk signal to DSP by
dividing the PCMDClk. The PCMDClk frequency is 1.000 MHz and is generated by dividing
the RFIClk 13 MHz by 13. The COBBA–GJP further divides the PCMDClk by 125 to get a
PCMSClk signal, 8.0 kHz.
PCMDClk
PCMSClk
PCMTxData sign extended
15
PCMRxData sign extended
Issue 1 03/01
HookDet HeadDet
High HIgh
Low Low
High Low *)
Low High
MSB
14 13 12 11 10
MSB
Nokia Mobile Phones Ltd.
System Module
Notes
Pull-ups in the transceiver
XEAR and XMIC loaded (dc)
XEAR unloaded (dc)
XEAR loaded (dc)
LSB
0
LSB
NSB-5
Page 33