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CONTENT:
i2c.h
i2c1.c
i2c2.s
WHAT ARE THESE FILES:
These files contain MPC8240 (Kahlua) I2C
driver routines. The driver routines are not
written for any specific operating system.
They serves the purpose of code sample, and
jump-start for using the MPC8240 I2C unit.
For the reason of correctness of C language
syntax, these files are compiled by Metaware
C compiler and assembler.
ENDIAN NOTATION:
The algorithm is designed for big-endian mode,
software is responsible for byte swapping.
USAGE:
1. The host system that is running on MPC8240
shall link the files listed here. The memory
location of driver routines shall take into
account of that driver routines need to run
in supervisor mode and they process I2C
interrupt.
2. The host system is responsible for configuring
the MPC8240 including Embedded Utilities Memory
Block. All I2C driver functions require the
content of Embedded Utilities Memory Block
Base Address Register, EUMBBAR, as the first
parameter.
3. Before I2C unit of MPC8240 can be used,
initialize I2C unit by calling I2C_Init
with the corresponding parameters.
Note that the I2CFDR register shall be written
once during the initialization. If it is written
in the midst of transers, or after I2C STOPs or
REPEAT STATRs, depending on the data written,
a long reset time may be encountered.
4. After I2C unit has been successfully initialized,
use the Application level API to send data or
receive data upon the desired mode, Master or
Slave.
5. If the host system is also using the EPIC unit
on MPC8240, the system can register the
I2C_ISR with the EPIC including other
desired resources.
If the host system does not using the EPIC unit
on MPC8240, I2C_Timer_Event function can
be called for each desired time interval.
In both cases, the host system is free to provide
its own timer event handler and interrupt service
routine.
6. The I2C driver routines contains a set
of utilities, Set and Get, for host system
to query and modify the desired I2C registers.
7. It is the host system's responsibility of
queueing the I2C I/O request. The host
system shall check the I2C_ISR return code
for I2C I/O status. If I2C_ISR returns
I2CBUFFEMPTY or I2CBUFFFULL, it means
I2C unit has completed a I/O request
stated by the Application API.
8. If the host system has more than one master
mode I2C unit I/O requests but doesn't want
to be intervented by being addressed as slave,
the host system can use the master mode
Application API with stop_flag set to 0 in
conjunction with is_cnt flag set to 1.
The first API call sets both stop_flag and
is_cnt to 0, indicating a START condition
shall be generated but when the end of
transaction is reached, do not generate a
STOP condition. Once the host system is
informed that the transaction has been
completed, the next Application API call
shall set is_cnt flag to 1, indicating a
repeated START condition shall be generated.
The last Application API call shall set
stop_flag
to 1.
9. The I2C_Timer_Event function containes
a user defined function pointer. It
serves the purpose of providing the
host system a way to use its own event
handler instead of the I2C_ISR provided
here.
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