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AMX 68000 Target Guide
5.3.2 MC68360 PIT Clock Driver
The AMX clock driver for the Motorola MC68360 Periodic Interval Timer (PIT) is ready
for use on the Motorola M68360QUADS Application Development System board. It is
configured to operate at approximately 1 KHz (1 ms period). Source code for this AMX
clock driver is provided in file CH68360T.C.
You must compile clock source module CH68360T.C and link the resulting object module
with the rest of your AMX application.
To use the AMX MC68360 PIT clock driver, you must create a clock ISP root as
described in Chapter 4.3. Simply check the box next to the MC68360 PIT clock ISP on
the list provided via the Prebuilt Clock ISPs... button.
Your Target Configuration Module will include a clock ISP root named _ch68360clk.
The clock driver's initialization procedure will install the pointer to this clock ISP into the
AMX Vector Table. On the Motorola M68360QUADS Application Development
System board, the pointer is installed into the entry for interrupt vector number 96 ($60).
Clock driver module CH68360T.C includes the clock initialization procedure
chclockinit and the clock shutdown procedure chclockexit. Insert procedure
chclockinit into the list of Restart Procedures provided in your System Configuration
Module at the point at which you wish the clock to be enabled during the launch. If you
intend to launch AMX for temporary execution, insert chclockexit into the list of Exit
Procedures at the point at which you wish the clock to be disabled during the shutdown.
Porting the MC68360 PIT Clock Driver
If you wish to change the MC68360 PIT timer frequency or use a different AMX vector
number, you must edit the definitions in source file CH68360T.C and recompile the
module. Edit instructions are included in the file.