EMAC PRIMER Instruction Manual page 23

a 32K RAM and you get a bad RAM error at 8000 or 4000, this is not a valid error. Pressing a key following this error
message will cause the diagnosis to continue. The RAM diagnostics should be completed in under 30 seconds, if the RAM
is okay. If an optional 32k RAM is in memory slot 1 and option jumper OJ3 is in position "A" you should turn off the
PRIMER and move the jumper to position "B" then turn it on again and run the diagnosis function. If the RAM is okay, and
you want the position "A" memory map again, turn off the PRIMER and move the jumper to its original position. Note that
no memory check is done on the RAM within the 8155 chip if a 32k RAM is in slot 1.
After the RAM diagnostics, the PRIMER will try to determine whether there is a serial port. If there isn't or if it is not
working, "n.u." will be displayed (indicating No UART). If a serial port is detected, it is examined to see if it is configured for
a local loopback test. It is configured for local loopback when the transmit and receive lines of the serial port are connected
to each other (pins 2 and 3 respectively of the DB9 connector CN2). This connection allows data transmitted by the UART
to be looped back to the UART, testing both the transmitter and the receiver.
If it is configured for local loopback and the serial port is working, the bytes 00 to FF hex will be transmitted and displayed
on the left 2 displays (this will happen quite rapidly at higher baud rates, so if you want to watch it, set JP1 to around 2400
baud). If there is a problem with the serial communications, you will hear a beep and "b.S." will be shown on the right 2
displays indicating a Bad Serial port. Pressing a key after this will resume the diagnostics and the UART will be disabled.
If the local loopback test runs without errors "L.L." will be shown on the left 2 displays, the UART will be disabled and the
diagnostics will continue. If "L.L." is not displayed and it has been verified that the transmit and receive lines were
connected together, there is a problem with the serial port circuitry.
If the PRIMER serial communications option is not configured for local loopback but instead is connected to a terminal, the
following will be shown on the terminal display:
UART test
>
If you type a key at the terminal, its hexadecimal ASCII value will be shown on the left two displays on the PRIMER, and
the character will be echoed back to the terminal display. For example if the letters "A" and "B" are typed at the terminal,
the following will be shown on the terminal display:
UART test
>A
>B
>
Note: If your terminal has the ability to "auto echo" you will see 2 characters displayed for each key pressed.
Also, after the RAM check is done, the hexadecimal representation of the A/D input will be shown on the right 2 displays. If
you want to test the A/D convertor you need to connect a variable voltage source, ranging from 0 to +5 volts, to the analog
input of the external digital I/O connector CN3 (this is above and to the left of the ADDRESS/REGISTER PAIR displays).
This can be simply done with a 10K potentiometer by connecting the wiper to the analog input and one of the other two
connections to +5V and the other to ground. Connector CN3 provides +5 volts on pin 22, analog input on pin 20 and
ground on pin 18. When the analog input voltage is ground the display should show "00". As you slowly increase the
voltage to 5 volts, the display will show a value from 02 to 3F hex. Also when the display no longer shows "00" the speaker
will begin to make a high pitched tone and which will gradually become lower pitched as the voltage approaches 5 volts.
Turn the voltage back to 0 and the tone will stop.
Each DIP switch is programmed to control an individual digital output LED. The best way to test the DIP switches and the
LEDs is to turn each of the switches on, allowing only one switch on at a time. Then turn all the switches on at once, and
finally turn all of them off.
Pressing one of the keys on the keypad will cause the hexadecimal value of that key to be shown on the middle two
displays. The hexadecimal values of the keys, starting at the top row and reading from left to right are 00 to 0F for the first
4 rows and 14 to 17 for the last row.
When you want to return to the Monitor Operating System, just press the reset button.
23