TCM4400 Datasheet, PDF (48/72 Pages) Texas Instruments – GSM/DCS BASEBAND AND VOICE A/D AND D/A RF INTERFACE CIRCUIT

4.7.4 Boundary-Scan Register
PWRDN SSCLK SSDR SSDX SSRST VCLK
VDR
TDI
IN
OUT
IN
OUT
IN
OUT
CTL
IN
VDX
VFS
RESET BFSR BCLKR
OUT
CTL
OUT
CTL
IN
IN
OUT
CTL
IN
BDR
BDX
BCLKX
BFSX
UCLKR
IN
OUT
CTL
OUT
CTL
OUT
CTL
IN
UCDR UCDX
UCSEL BDLON BULON BCAL
BENA
IN
OUT
CTL
IN
IN
IN
IN
IN
TDO
4.8 Power-Down Functional Description
During certain mobile activity (such as paging, conversation mode, or idle), it is possible to disable some
TCM4400 functions in order to lower the power consumption. For example, it is possible to disable the
internal functions dedicated to radio transmission during GSM-idle mode. It is also possible to disable the
internal demodulator path during the transmit window.
There are three ways to control the power consumption of the internal blocks as described in the following
paragraphs.
4.8.1 Direct Control with Internal Register
With this method, the following internal blocks are powered down:
• DAI GSM tests: bit DAION of register VBCTL3
• Transmit and receive voice path: bit VULON of register VBCTL1 and bit VDLON of register
VBCTL 2
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