Fluke 8842a instruction manual Troubleshooting, Switches Configuration

Maintenance	6
TROUBLESHOOTING
f6-19.wmf
Figure 6-19. Option -05 Service Position

Table 6-24. Diagnostic Modes

A3

1

1

1

0

NOTES:

SWITCHES

A2 A1

01

11

X0

Xx

CONFIGURATION

Static, odd-port bits = 1, even-port bits = 0

Static, odd-port bits = , even-port bits = 1

Dynamic

Read/Write

∙“x” means switch setting does not matter.

∙“Static” means the Out-Guard μC I/O port bits programmed as outputs are driven to a constant logic 1 or 0 level (as determined by switch A2).

∙“Dynamic” means the Out-Guard μC I/O port bits programmed as outputs are driven with a 610 Hz, 50% duty cycle square wave. All odd port bit numbers are 180 degrees out of phase with even port bit numbers.

∙“Read/Write” means that data is read from and written to the NEC7210 IEEE chip (U901) when DS (U901-8) is low. R/W (U901-7) determines whether the data is being read from or written to the NEC7120. The address bits are always 3 (0011) and the data bits are incremented each time.

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