Digital Section; Digital Section Block Diagram - Agilent Technologies 4339B Service Manual

Digital Section

Figure 4-6 shows the Digital Section block diagram.
The digital section consists of the A2 CPU Board Assembly and other peripheral assemblies
such as the keyboard and LCD. The section communicates with the A1 Main Board Assembly in
order to control the latches, switches, and other components on the A1 Assembly and receive
the measurement data. For the same purpose, the A2 Assembly also communicates with the A3
Ammeter Assembly via the A1 Assembly and four optical bers. The GPIB interface on the A2
Assembly allows the 4339B communicate with a controller. The handler interface on the A1
Assembly allows the 4339B communicate with an external handler.
Note Because of required high dc isolation between the A3 Assembly and other
assemblies, the A3 Assembly communicates with other assemblies via optical
bers.
The A2 CPU Board Assembly includes a processor, ROM, EEPROM, jumpers, switches, and
LEDs.
ROM (A2U11) stores the rmware which controls all the 4339B operation and functions. The
ROM is mounted in a socket for easy replacement.
EEPROM (A2U1) stores the unit unique data, such as the adjustment data and the operator
unique data, such as the operator saved measurement setup condition. The EEPROM will
4-8 T roubleshooting
Figure 4-6. Digital Section Block Diagram