Phase #14 - Enter Isc Debug Mode Test - AT&T 3B2 Off-Line Diagnostic Manual

Phase Descriptions - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Phase #14
~
Enter ISC Debug Mode Test
Phase Name:
Type:
Function:
Test:
Time:
Warnings:
Notes:
Send Debug Command to ISC
Interactive
This phase is used to enter the ISC ROM resident debug monitor.
Test 1 - issues the debug command to the ISC.
1 second
A terminal must be connected to Channel B of the ISC to run this phase.
The ISC card contains a debug program in ROM which uses the INTEL 80186
CPU and Channel B of the 8274 Universal Synchronous/Asynchronous
Receiver/Transmitter (USART) to control an American Standard Code for
Information Interchange (ASCII) terminal. This debug program is useful while
developing and testing software developed for Channel A of the ISC. This
facility cannot be used to debug code for Channel B.
Since the ISC does not have an internal baud rate generator, the transmit and
receive clocks must be provided to Channel B while using the ASCII terminal.
The ASCII terminal setup should be for 7-bit word length, 1 stop bit, no parity,
and 9600 baud (bits per second). Figure 6-1 shows the ISC to terminal pinout
information.
ISC
OB-25
OB-25
ASCII
CHANNEL B PIN PIN TERre1INAL
TO 2
) 3
RO
RO 3
E
2
TO
OTR
20
I
)
6
OSR
OSR 6
E
I
20
OTR
I
I
RTS
4
:
J
I
)
8
OCO
CTS
5
E
I
I
OCO
8
E
I
c=;
4
RTS
I
I
5
CTS
TXC 15
~
THESE INPUTS MUST BE DRIVEN BY AN
RXC
17
EXTERNAL SOURCE WHICH CAN PROVIDE
A SQUARE WAVE FROre1 -12V TO +12V AT
A FREQUENCY OF ABOUT 153.6 KHZ.
THIS WAVEFORre1 REPRESENTS A 16X CLOCK
OF 9600 BAUD AT RS-232 SIGNAL LEVELS.
Figure 6-1: ISC to ASCII Terminal Connection for Debug Operation
6·24 OFF·LlNE DIAGNOSTIC MANUAL