9600 Service Manual - gmecorp-usa.com

18 C-Arm Control
7-Segment Displays
Two 7-segment LED displays (U1 & U2) are used to indicate the status of the
Technique Processor PCB.
NOTE: The hex value 00 is displayed after the Technique Processor has completely
booted.
For a complete listing of these hexadecimal status codes, refer to the BIOS ROM
Code in the C-Arm Software Section of this manual.
Switch S1
S1 is a four position DIP Switch used for selection of communications and disk
type. Switches 1 and 2 must be on (on -02 PCBs and higher) to enable serial
communications on the 9600 C-Arm. Switches 3 and 4 are not used.
Jumper E1
Configuration jumper E1 is not used.
COMMUNICATIONS
Refer to System Communications in this section for details of the
communications circuitry.
DUAL PORT RAM (A/D INTERFACE)
U31 is a Dual Port RAM used to store bytes of data representing analog signals
digitized by circuitry on the Analog Interface PCB as shown in Figure 11.
The Technique Processor selects one of the sixteen analog input signals via a 4bit
address (AMUXSEL0-3) via U11, U40, and U41. After an address has been
generated, the SAMPLE signal is made active. This signal latches the selected
analog signal into U8, a sample and hold chip.
Simultaneously, U9 on the Analog Interface PCB inverts the logic level of the
SAMPLE signal for U7, the A/D converter. This inverted signal is applied to the
“Convert” control line for U7. This A/D chip digitizes this analog signal into an 8bit
digital byte. This byte of data is sent back to the Technique Processor and is
stored in the Dual Port RAM.
Since this is a continuous process, the Dual Port RAM contains byte values for
all sixteen analog signals. By using the Dual Port RAM, the Technique
Processor can access the status of any of these analog signals without having to