The STBY on Pin 28 of BA5954 is an output-enabling signal, and only when the pin is in
high power level, there will be output of drive voltage on the output terminal.
Chapter III Operating Principle of Decoding Circuit
The decoding circuit of the player mainly consists of decoding chips (including MT1389, SDRAM
AE45164016 and FLASH ROM 29LV160BE) and audio DAC CS4360.
I. Control Circuit of System
1. Reset circuit is as the Figure VI:
Figure VI
The reset circuit of the player consists of triode Q204 9014, reset capacitor TC217 100uF/16V and
phase inverter U205 HCU04. In starting up, as the terminal voltage of capacitor cannot be changed
suddenly, the basic of Q204 is in low power level. After the cut-off of Q204, its emission polar is
in low power level, after secondary phase inversion by U205 and regulation, the low power level
reset signal is outputted to the Pin 110 of MT1389 to reset MT 1389.
When the recharging of TC217 is finished, the base of Q204 will be in high power level, Q204 will
be cond ucted, and the emission polar is in high power level. After the secondary phase inversion
and regulation by U205, a high power level is outputted and added to the Pin 110 of MT1389 to
maintain high power level during its normal operation.
2. Clock circuit
The crystal oscillator of X201 27MHz, C275/27PF, C276/27PF and phase inverter HCU04 form
into clock oscillation circuit, and the clock signals generated are added to the pins 229 and 228 of
MT1389 through R244 and 4248 to provide operating clock for MT1389.
3. Data communication circuit
The data communication circuit of the player consists of decoding chip MT1389, SDRAM,
AE45164016 and FLASH ROM 29LV160BE, as the Figure VII:
MT1389 is a piece of super large integrated circuit, with the operation voltage of +3.3V and +1.8V.
Its functions include: RF small signal preposition processing, digital servo, digital signal
processing and accomplishing MPEG decoding and video coding. The built- in MCU of MT1389 is
