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The problem can usually be traced to:
1. a defective chip;
2. a solder cross or bad solder joint or
3. a misplaced or incorrectly oriented
component.
A BRIEF LIST OF PROBLEMS WITH SUGGESTED POINTS TO CHECK
ARE GIVEN BELOW.
NONE OF THE PORTS RESPOND
1.
Check the jumpering of the EXTERNAL ADDRESS
JUMPER AREA.
2.
Check the Board Enable Circuits.
low when the processor executes an output
instruction to the MIO Board Addrsss.
ONE OF THE PORTS DOES NOT RESPOND
1.
Check the jumpering of the Internal Address
Jumper Area.
2.
Check U23;
Port Select Signals.
Load Signals and four Read Enables.
N O I N P U T F R O M A N Y I N P U T P O R T S
1.
Check the Input Bus Drivers U42 and U43.
Check for Enables U43-1, U43-15, and U42-15,
going low.
NO OUTPUT TO ANY OUTPUT PORT
1.
Check the Output Bus Drivers U41 and U42.
Check for Enables U42-1 and U41-1 going low.
SIO PORTS
NO OUTPUT FROM SIO TO EXTERNAL DEVICE 1
1.
Check U7-25 UART Transmit Data Line.
Data is present here, carefully check the
jumpering of the OJA and/or OJA Line Drivers.
If Data is not present, check
tion Jumpers and check all Control Inputs to
the UART U7 (especially U7-23, UART Data Load).
The outputs of U23 are the Internal
There are four Register
MIO
Debugging Information
U18-8 goes
If
SIO Configura
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