Epson PC AX Technical Manual page 206

DIAGRAMS AND REFERENCE MATERIALS
6) SN74LS612 DMA Page Register Check
The SN74LS612 DMA Page register check performs a WRITE/READ
check on the 15 registers (Port Nos. 81h to 8Fh) of the SN74LS612
Page Register.
The test data is used in the sequence of "OOh", "SSh", "Oaah",
and "Offh". If an error is detected, the following message will be
displayed:
+-----------------------------------------------------------------+
I I
I I
: Error code
=
106 :
: 612 DMA PAGE REGISTER ERROR
l
1 I
I I
+-----------------------------------------------------------------+
7) 8237 Memory Refresh Check
The 8237 Memory refresh check performs a repeated check on the
refresh detect bit of Port No. 61h, and checks if its status makes
a change.
The program displyas an error message if the status does not
change.
+-----------------------------------------------------------------+
1 I
I I
: Error code
=
105 :
: 8237 DMA REFRESH ERROR
l
I I
I 1
+-----------------------------------------------------------------+
8) 8042 Keyboard Controller Check
The 8042 Keyboard Controller check performs a check on the
operating status of the Keyboard Controller.
a. The status of the Keyboard Controller is repeatedly checked,
and the program displays an error message if its input buffer
is not empty.
+-----------------------------------------------------------------+
I 1
I I
: Error code
=
107
I
: 8042 TIME OUT ERROR :
I I
I I
+-----------------------------------------------------------------+
b. The Self-test command is output to the Keyboard Controller so
that it will execute a self-diagnostic test. If an error is
detected, the following message will be displayed:
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