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