Datasheet

101
4341H–MP3–10/07
AT8xC51SND2C/MP3B
15.3.3 Precharge Control
The power up of the circuit can be performed independently for several blocks. The sequence
flow starts by setting to High the block specific fastcharge control bit and subsequently the asso-
ciated power control bit. Once the power control bit is set to High, the fast charging starts. This
action begins a user controlled fastcharge cycle. When the fastcharge period is over, the user
must reset the associated fastcharge bit and the block is ready for use. If a power control bit is
cleared a new power up sequence is needed.
The several blocks with independent power control are identified in Table 15-29. The table
describes the power on control and fastcharge bits for each block.
Table 15-29. Precharge and Power Control
Note: Note that all block can be precharged simultaneously.
Powered up block Power on control bit Precharge Control Bit
Vref & Vcm generator ONMSTR
PRCHARGE
(reg 12; bit 1)
Left line in amplifier ONLNIL PRCHARGELNIL
Right line in amplifier ONLNIR PRCHARGELNIR
Left line out amplifier ONLNOL PRCHARGELNOL
Right line out amplifier ONLNOR PRCHARGELNOR
Left D-to-A converter ONDACL Not needed
Right D-to-A converter ONDACR Not needed
Auxiliary input amplifier ONAUXIN PRCHARGEAUXIN
PA Driver output ONPADRV PRCHARGEPADRV