Specifications

2. EXPLANATION OF OPERATION
Item n°. : W1404621 Page 2-6 Version 01.02
2.3. PC interface
This board mainly acts as a communication interface between the PC SBC-456/E board and
the other devices like the
MAGLIFE C PLUS. or the Magfile via series and optical links.
It controls the starting up and turning off of the main power supply, and also controls the power
supply to the various modules depending upon their use, via the power supply board.
It also allow the maintenance of the MAGSCREEN's power supply even if there isn't any data
who passed in the optic fibers. This is taken by a function from the automatic cutoff board.
Two EXAR XR82C684 circuits act as the series connection with the modules:
- U2 (C5) is used to read datas from the system configuration connector,
- U3 (C4is used to communicate with external devices such as MAGFILE, to download datas
and to acquire the informations come from the MAGLIFE C PLUS.
One XILINX XC3042PQ100 circuit is used to reduce the surface of the printed circuit:
- U1 (C6) takes charge of decoding addresses, controlling the keypad and generating
sounds.
2.3.1. Link with the keypad
The keypad includes 5 keys and a rotary button.
Signals BR0, BR1, BR2, BR4 and BR5 from the rotating button all go through a
trigger gate and XILINX U1 (C6) which includes anti-rebound circuits.
The 5 signals from the keys are also reshaped by U1.
All these bits are sent to the data bus by U1, with the exception of the "Graph" key
signal, which is sent through one of the U2 EXAR circuits.
2.3.2. The sound function
A small speaker is connected onto this board. It supplies 4 sounds:
- 3 sounds with different frequencies and amplitudes (4 levels) and of fixed
duration,
- a continuous sound with a variable frequency and amplitude (4 levels).
The first three sounds are supplied by logical outputs IN1, IN2, IN3 of U1 (C6).
IN4 is a variable cyclic ratio signal. Associated with U22 (A6), a variable voltage is
obtained to control the VCO of U26 (A6) and obtain a variable frequency. Signals
OP8 - OP15 from U3 (C4) are used to control the analogue switches and the
amplitude of the sound. Signal S-ON (B8) validates the emission of a sound.