Peritek VCD-V, User Manual

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Peritek
6-6 Troubleshooting
Note
When starting this procedure, make sure that the graphics board is not
plugged in.
enter MM FFFFC000;L <CR> ;examines one CSR location
enter
MM FFFF8000;L <CR>
;examines the line buffer base address
You will get an " Exception: Access Fault (Local Off Board) " if there is
no device already installed which uses the board's addresses. This is what
should happen for both of these attempted memory examine operations.
Note
Now install the board following the procedure in Section 2.3.
Power up and don't let the debugger boot the operating system. Use the
debugger to verify that board registers can now be read (see below). The
Line Buffer cannot be read until the MEMON enable bit in the graphics
board CSR is set. Since we can't use the bottom of A16 space in a 167 (or
187), it is also necessary to load the Line Buffer Address Register (LBAR,
at FFFFC008). This is because the register comes up zero.
enter
MM FFFFC000;W <CR>
receive FFFFC000 4000?
enter
60 <CR>
;sets MEMON and CRTCON
receive
**WARNING:NO MATCH**
;get an error because the 4000 bit is lways set
enter
. <CR>
;end the dialog
enter
MM FFFFC008;W <CR>
receive
FFFFC008 0000?
enter 20 <CR> ;set line buffer address to FFFF8000
receive FFFFC00A 0020?
enter
. <CR>
;end the dialog
enter MD FFFF8000:400;B <CR> ;dumps 1024 bytes starting at FFFF8000
receive a bunch of bytes
enter
MD FFFF8022:1;W <CR>
;dumps the 34020 HSTCTLH register
receive
FFFFC008 8010
;this is the right value for a halted 34020
enter
. <CR>
;end the dialog
You will get an error message (which is not what you want) if there is no
response. If indeed the board appears to be dead, call Peritek for further
assistance.