Circuit Notes
3 - 1
Revision 1 - 07 July
1999
Event 4
TECHNICAL MANUAL
3. Circuit Notes
The Event 4 uses a main CPU to provide all processing functions. The CPU
communicates with the front panel PCBs via the front panel card bus.
3.1 Processor Card
The major functional blocks are as follows:
Function
IC Number
Core CPU
IC1-8, IC33, IC30, OSC1
Boot EPROM
IC25
FLASH ROM
IC11-14
RAM Bank 1
IC16-19
Floppy Disk Drive Controller
IC48
DMX output
IC53, IC38, IC39, IC50, IC51
MIDI
IC48, IC35, IC52
VGA output
IC6, IC57-60, IC66
Reset/power fail/RAM power
IC15
Real time clock
IC31
Front Panel Card bus
IC9, IC10
Expansion bus
IC24, IC26-29
3.1.1 Boot ROM, FLASH, and RAM
The CPU memory consists of a Boot EPROM (IC25), four FLASH ROMs (IC11,
IC12, IC13, IC14), and four static RAMs (IC16-19).
The CPU card has the capacity to be fitted with a maximum of 2MBytes program
memory (four x 29F040 devices) and 2MBytes show memory (four x 512Kbyte
devices).
Only AMD brand 29F040 FLASH devices should be used with boot software versions
up to 0.5.
3.1.2 Trim procedure
The adjustment trim on the CPU card adjusts the point where the CPU is informed that
power is failing. If a console is dropping its memory, trimpot T1 may be out of
adjustment and should be adjusted as follows:
1.
Save any necessary console information to diskette
2.
Turn T1 fully anticlockwise
3.
Place a shunt across J1
4.
Switch console on and wait until it has completely started up
5.
Slowly adjust T1 until LED L3 lights
