GE LOGIQ 9 - Page 297

GE MEDICAL SYSTEMS PROPRIETARY TO GE
D
IRECTION 2294854-100, REVISION 3 LOGIQ™ 9 PROPRIETARY MANUAL
Chapter 7 Diagnostics/Troubleshooting 7-79
7-13-9 I
2
C Buss
I
2
C is a clock and data bus. I
2
C control is embedded in the master chip i960 RP. The LOGIQ™ 9
contains four separate I
2
C buses. The first bus is located in the BEP:
- BEP PC2IP->PC/DGIO->IIO->EIO
-PC/DGVIC
- Patient I/O
One of the basic functions of this bus is carrying Start-up/Shut-down sequence for the LOGIQ™ 9. It
also carries control signals for the PRINT keys. If the PRINT keys function fine to PRINT on a B/W
printer or color printer but the Stand-by switch does not work to shut-down the system, I2C bus should
be functioning normal but the ON/OFF switch itself (pinched cable or bad sticky button) could cause the
problem.
The other three I
2
C buses are located in the front end:
- EQ/EBM->RFAmp->XDIFF->Transducer (For E8C temp. sensing)
- EQ/EBM->TDs (Serial EEPROM for the VPD
Each TD board has an Analog Devices A/D converter with an I
2
C interface on it for
diagnostics. The converter reads transmit Vref (variable, 0-2V), the fixed A/D converter Vref,
and has a built-in temperature sensor. Diagnostics reads back all of these over the I
2
C bus;
the I
2
C master is on the EQ board.
- EQ/EBM->Back Plane->Power Supply (Fan speed and temperature control, +5, +3.3, +-6 V,
+12, ProBias 120 V, Probe Rail +-100V)
These I
2
C buses in the front-end card cage are for controlling the voltage on the TD boards,
temperature control and FEPS fan control.
There is no classical type of sensor for temperature in the LOGIQ™ 9 Card Cage. There is an integrated
circuit for the temperature sensing that is located on the Front End boards including TDs and EQ/EBM
board.
A/D diagnostic goes through on the I
2
C bus on the TDs. PCI bus is used for the communication between
the EBM/EQ, SCB and BEP. Since there is no PCI bus on the TD, XDIFF, RF and Back Plane, I
2
C bus
goes through these boards from the EQ board.
NOTE: The ultrasound data for beamforming is transferred to the next TD boards through the Back
Plane. I
2
C buses never carry any ultrasound data!