EPC2LC20 Configuration Device

The EPC2LC20 is a Configuration Device which is designed for SRAM-Based LUT Devices.

EPC2LC20 absolute maximum ratings: (1)Supply voltage: -0.2 to 7.0 V With respect to ground; (2)DC input voltage: -0.2 to 7.0 V With respect to ground; (3)DC VCC or ground current: 50 mA; (4)DC output current, per pin: -25 to 25 mA; (5)Power dissipation: 250 mW; (6)Storage temperature: -65 to 150℃; (7)Ambient temperature: -65 to 135℃; (8)Junction temperature: 135℃.

EPC2LC20 features: (1)Serial device family for configuring APEXTM II, APEX 20K (including APEX 20K, APEX 20KC, and APEX 20KE), MercuryTM, ACEXR 1K, and FLEXR (FLEX 6000, FLEX 10KE, and FLEX 10KA) devices; (2)Easy-to-use 4-pin interface to APEX II, APEX 20K, Mercury, ACEX, and FLEX devices; (3)Low current during configuration and near-zero standby current; (4)5.0-V and 3.3-V operation; (5)Software design support with the AlteraR QuartusR II and; (6)MAX+PLUSR II development systems for Windows-based PCs as well as Sun SPARCstation, and HP 9000 Series 700/800.

Microcontroller interface using RS485 & RS422

After a period of research, I found out that RS485 and RS422 is in fact the same.

RS422 is a duplex configuration. RS422 using 4 wire to communicate in both direction. One pair of wire to do transmit and the other pair to receive. Both sides is able to transmit and receive at the same time.

RS485 is a half duplex configuration. RS485 using only 2 wire to communicate in both direction. With only two wire, it means that when one side is transmitting, the other side of the communication line will be receiving. Both side cannot be transmitting at the same time. For RS485 transceiver, use MAX485 or MAX3485. They have the same pin out except that MAX485 uses 5V supply, MAX3485 uses 3.3V supply.

RS422 can be connected to work with RS485 to either receive or transmit date, but not both. RS422 can be wired directly using a pair of wire, +ve to +ve, -ve to -ve terminal. For RS422 transceiver, use MAX488 or MAX3488. They have the same pin out except that MAX488 uses 5V supply, MAX3488 uses 3.3V supply.

3.2 The 8255 a PI/O - Chip 82C55A

The 82C55A is a high performance CMOS version of the industry standard 8255A . It is a general purpose programmable I/O device which may be used with many different microprocessors. There are 24 I/O pins which may be individually programmed in 2 groups of 12 and used in 3 major modes of operation. The high performance and industry standard configuration of the 82C55A make it compatible with the 80C86, 80C88 and other microprocessors. Static CMOS circuit design ensures low operating power. TTL compatibility over the full military temperature range and bus hold circuitry eliminate the need for pull-up resistors.

 The device comprises three 8 bit ports whereby port c can be sub-divided into two 4 bit groups. Each of these three ports is addressed by A0 and A1 . With it's read, write, the chip select and data signals it looks and behaves like a tiny ROM or a RAM with only three bytes.

    To switch between 'RAM-' and 'ROM-mode' the 8255 has a mode register where three working modes can be selected. The mode register is selected when A0 and A1 are set to high (+5V).

    The three modes are:

    Mode 0: basic input / output
    Mode 1: strobed input / output
    Mode 2: bi-directional bus

For our purpose only mode 0 was interesting, but the device may be switched into each with the setup supplied in this document.
To work with the three ports they must first be initialized. This is done by writing the proper control word into the control register. Figure 11a shows the definition of the control word. While bit D2, D5, D6 and D7 define mode 0..2 the bits D0, D1, D3 and D4 define the settings of the ports to input- or output-mode. In other words you need to 'program' or switch the 82C55 every time you want to change a port data flow direction.
If 'all input mode' in mode 0 is requested the control word would be 10011011bin = 9Bhex = 155dec. If 'all output mode' in mode 0 shall be selected the control word would be 10000000bin = 80hex = 128dec.

Diagram Block IC TDA7377

The TDA7377 is a new technology class AB car radio amplifier able to work either in DUAL BRIDGE or QUAD SINGLE ENDED configuration.



The exclusive fully complementary structure of the output stage and the internally fixed gain guarantees the highest possible power performances with extremely reduced component count. The on-board clip detector simplifies gain compression operation. The fault diagnostics makes it possible to detect mistakes during car radio set assembly and wiring in the car.

The stand-by can be easily activated by means of a CMOS level applied to pin 7 through a RC filter. Under stand-by condition the device is turned off completely (supply current = 1µA typ.; output attenuation= 80dB min.). Every ON/OFF operation is virtually pop free. Furthemore, at turn-on the device stays in muting condition for a time determined by the value assigned to the SVR capacitor.

While in muting the device outputs becomes insensitive to any kinds of signal that may be present at the input terminals. In other words every transient coming from previous stages produces no unplesantacoustic effect to the speakers.