CALIBRE
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| This is a period of time (in micro seconds) to wait for the required bus status. | |||
| If this | |||
| int sclk |
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| This is the clock rate (bit rate for the I2C serial bus) when operating as a | |||
| master. |
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| Value of sclk | Approximate | ||
| 0 | 90 |
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| 1 | 45 |
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| 2 | 11 |
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| 3 | 1.5 |
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Parameters returned | None. |
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Prerequisites | None. |
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Functional description | This function | characterises the PC and initialise adapter ready for I2C | ||
| transfers. |
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4.4.5.sendaddress
Function specification | Int sendaddress(int slaveaddress, int setnack) | |
Parameters are: | int slaveaddress | |
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| This is the address to be accessed via the I2C, e.g. A0H. |
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| int setnack |
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| This controls whether the Parallel I2C Communications Adapter transmits an |
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| Acknowledge down the I2C Bus on reception of a byte. The last byte received |
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| during a transfer must not be acknowledged, in all other cases acknowledge |
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| must be enabled. If setnack = 0 then acknowledge is enabled, if setnack = 1 |
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| then acknowledge is disabled. Therefore, if a read (odd numbered) address is |
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| being sent AND only 1 Byte is to be read, setnack should be set to = 1; in all |
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| other cases it must be clear = 0. |
Parameters returned | int ErrCode. | |
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| If the transfer time out occurs error code 8001H is returned otherwise the |
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| status is returned. |
Prerequisites | The adapter must be configured for PC and application by running setup. | |
Functional description | The function waits for the bus to be free. Then sends the slave address with | |
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| the appropriate acknowledge. |
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| The acknowledge is set ready for the data transfer after the address and |
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| hence in read mode (odd address being sent) if only one byte is to be read |
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| the setnack parameter must equal 1. If more than one byte is to be read or if |
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| in write mode (even address being sent) then setnack must equal 0. |
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| The function waits for the address to be sent. Should a |
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| the sending of an address then an error code 8001H is returned, otherwise |
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| the status is returned. |
4.4.6. | writebyte |
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Function specification | Int writebyte(int wrData) | |
Parameters are: | int wrData | |
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| This is the byte of data to be written. |
Issue 1.3 |
| Page 21 |
22/07/99
