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8.  FLASH  MEMORY

The decoder board supports 70ns Flash memories. Currently 4 configurations are supported:

• FLASH_512K_8b
• FLASH_1024K_8b
• FLASH_512Kx2_8b
• FLASH_512Kx2_16b

The MT1379 permits both 8- and 16-bit common memory I/O accesses with a removable storage card via the host interface.

9.  SERIAL  EEPROM  MEMORY

An I2C serial EEPROM is used to store user configuration (i.e. language preferences, speaker setup, etc.) and software

configuration.. Industry standard EEPROM range in size from 1kbit to 256kbit and share the same IC footprint and pinout. The

default device is 2kbit, 256kx 8, SOIC8 SGS Thomson ST24C02M1 or equivalent.

10. AUDIO INTERFACE AUDIO SAMPLING RATE AND PLL COMPONENT CONFIGURATION

The MT1379 audio mode configuration is selectable, allowing it to interface directly with low-cost audio DACs and ADCs. The

audio port provides a standard I

2

S interface input and output and S/PDIF (IEC958) audio output. Stereo mode is in I

2

S format

while six channels Dolby Digital (5.1 channel) audio output can be channeled through the S/PDIF. The S/PDIF interface consists

of a bi-phase mark encoder, which has low skew. The transmit I

2

S interface supports the 112, 128, 192, 256, 384, and 512

sampling frequency formats, where sampling frequency Fs is usually 32 kHz, 44.1 kHz, 48 kHz, 96 kHz, or 192 kHz. The audio

samples for the I

2

S transmit interface can be 16, 18, 20, 24, and 32-bit samples.

For Linear PCM audio stream format, the MT1379 supports 48 kHz and 96 kHz. Dolby Digital audio only supports 48 kHz. The

MT1379 incorporates a built-in programmable analog PLL in the device architecture in order to generate a master audio clock.

The MCLK pin is for the audio DAC clock and can either be an output from or an input to the MT1379. Audio data out (TSD) and

audio frame sync (TWS) are clocked out of the MT1379 based on the audio transmit bit clock (TBCK). Audio receive bit clock

(RBCK) is used to clock in audio data in (RSD) and audio receive frame sync (RWS).

11. FRONT PANEL

11.1.  VFD  CONTROLLER

The VFD controller is a NEC uPD16311. This controller is not a processor, but does include a simple state machine which

scans the VFD and reads the front panel button matrix. The 16311 also includes RAM so it can store the current state of all

the VFD icons and segments. Therefore, the 16311 need only be accessed when the VFD status changes and when the button

status is read. The MT1379 can control this chip directly using PIO pins or can allow the front panel PIC to control the VFD.

11

12.  CONNECTORS

12.1.  SCART  CONNECTORS

Pinout of the scart connector:

1 à Audio Right Out
2 à Audio Right In
3 à Audio Left / Monu Out
4 à Audio Gnd
5 à Blue Gnd
6 à Audio Left / Mono In
7 à Blue
8 à Control Voltage
9 à Green Gnd
10 à Comms Data 2
11 à Green
12 à Comms Data 1
13 à Red Gnd
14 à Comms Data Gnd
15 à Red
16 à Fast Blanking
17 à Video Gnd
18 à Fast Blanking Gnd
19 à Composite Video In
20 à Composite Video Out
21 à Shield

Some cheaper SCART cables use unshielded wires, which is just about acceptable for short cable lengths. For longer lengths,

shielded co-ax cable become essential.

Scart Signals:
Audio signals
0.5V RMS, <1K output impedance, >10K input impedance.
Red, Green, Blue
0.7Vpp ±2dB, 75R input and output impedance. Note that the Red connection (pin 20) can alternatively carry the S-Video

Chrominance signal, which is 0.3V.
Composite Video / CSync
1Vpp including sync, ±2dB, 75R input and output impedance.Bandwidth = 25Hz to 4.8MHz for normal TV Video de-emphasis

to CCIR 405.1 (625-line TV)

12

Fast Blanking
75R input and output impedance. This control voltage allows devices to over-ride the composite video input with RGB inputs,

for example when inserting closed caption text. It is called fast because this can be done at the same speeds as other video

signals, which is why it requires the same 75R impedances.

0 to 0.4V: TV is driven by the composite video input signal (pin 19). Left unconnected, it is pulled to 0V by its 75R

termination.

1V to 3V: the TV is driven by the signals Red, Green, Blue and composite sync. The latter is sent to the TV on pin 19.

This signal is useful when using a TV to display the RGB output of devices such as home computers with TV-

compatible frame rates. Tying the signal to 5V via 100R forms a potential divider with the 75R termination,

holding the signal at around 2V. Alternatively, if a TTL level (0 to 5V) negative sync pulse is available, this will

be high during the display periods, so this can drive the blanking signal via a suitable resistor.

Control Voltage
0 to 2V = TV, Normal.
5 to 8V = TV wide screen
9.5 to 12V = AV mode

12.2. CABLE DIAGRAM

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13

13.  CIRCUIT  DESCRIPTION

13.1. POWER SUPPLY

• Socket PL1 is the 220VAC input.
• 2.5A fuse F1 is used to protect the device against short circuit.
• Line filters and capacitors L1, C1, L5 and L6 are used to block the parasitic coming from the mains. They also prevent the

noise, produced in the circuit, from being injected to the line.
• Voltage is rectified by using diodes D1, D2, D3 and D4.  Using capacitor C3 (470mf) a DC voltage is produced. (310- 320VDC).
• The current in the primary side of the transformer TR3 comes to the SMPS IC (IC3 TOP223Y). The SMPS IC has a three-pin

TO-220 case and a cooler is mounted on it. It has a built-in oscillator, overcurrent and overvoltage protection circuitry and runs

at 100kHz. It starts with the current from the primary side of the transformer and follows the current from the feedback winding.
• Voltages on the secondary side are as follows:  -22V, -12V, 3.3V, 5V, 15V.
• D14 TL431 is a constant current regulator. TL431 watches the 5 volts and supplies the required current to IC2. There are a

LED and a photo transistor in IC2. The LED inside the IC2 transmits the value of the current from D14 to phototransistor.

Depending on the current gain of the phototransistor IC3 keeps the voltage on the 5-volt-winding constant.
• Adjustable voltage regulator IC5  (LM317) supplies 12 Volts.
• When the device enters stand-by mode, transistor Q2 starts to conduct and pulls the adjust pin of IC5 to ground, where this

cuts 12Volts off.
• –22 Volts is used to feed the VFD (Vacuum Fluorescent Display) driver IC on the front panel.
• Transistor Q4 and zener diode D14 are used to regulate +12 Volts. This voltage is used to feed op-amps on the back panel.

13.2. FRONT PANEL

• All the functions on the front panel are controlled by U7 (MT1379) on the mainboard.
• U7 sends the commands to IC2 uPD16311 via socket PL1 (pins 3,4 and 5).
• There are 16 keys scanning function, 2 LED outputs, 1 Stand-by output and VFD drivers on IC2.
• Pin 52 is the oscillator pin and is connected via R5 56K.
• LED D6 is red in stand-by mode and green when the device is on. When entering stand-by mode, pin 48 goes HIGH (+5V)

and controls the transistor Q2 on the power board.
• Vacuum fluorescent display MD2 is specially designed for DVD.
• The scanned keys are transmitted via IC2 pin 5 and 6 to U1 on the mainboard.
• IR remote control receiver module IC3 (TSOP1836) sends the commands from the remote control directly to U1.
• Socket PL2 carries the VFD filament voltage and –22 Volts.

13.3 BACK PANEL

• There are 1 SCART connector (PL4), 2 pieces RCA audio jacks, for audio output, 1 coaxial digital audio output JK3 and 1 laser

digital audio output PL5 on the back panel.
• TOTX176 is used for laser output.
• For coaxial audio output SPDIF is used.
• Q22 .. Q27 transistors are to mute the audio outputs while switching the state of the unit(power on/off)
• There are two op-amps in U14, U16 and U18. They are used for left,right,rear left and right, subwoofer center audio channels.

The feedback resistor is amplifying the gain.
• SCART pin 8 controls 16:9 and 4:3 mode using Q28,Q29 and Q30.
• When the pin8 output of the scart becomes 5 Volts, 4:3 mode is selected and 16:9 mode is selected when this output becomes

0. The circuit is adjusted to output 12 Volts for 4:3 mode and 6 Volts for 16:9 mode.
• Transistors Q28,Q29 and Q30 transmit these voltages when the device is turned on and cuts them off when it is turned off.
• FBL on pin 16 transmits 5 Volts via transistors Q12 and Q14 when the device is on.