The Cascade Driver API functions can be grouped according to their purpose, as follows:
| DR_ApInitIPC |
| DR_ApConnectIPC |
| DR_ApCloseIPC |
| DR_ApCommand |
| DR_ApReadPoint |
| DR_ApWritePoint |
| DR_ApListPoints |
| DR_ApDescribePnt |
| DR_ApPointBufAddress |
| DR_ApReadBlock |
| DR_ApWriteBlock |
| DR_ApListBuffers |
| DR_ApDescribeBuffer |
| DR_ApUpdateBuffers |
| DR_ApReadStatus |
| DR_ApReadControl |
| DR_ApWriteControl |
All these functions are described in detail in the Reference. They are intended to be quite generic, to provide a consistent interface for different types of cards. However there are some exceptions for specific drivers, which are discussed in this chapter.
The CIF card defines specific buffers and block lengths for block functions where valid data is available, as follows:
The DR_ApReadBlock and DR_ApWriteBlock functions access the process I/O data area of the card. The offset and size parameters specify what portion of the buffer area to transfer, and is dependent on the field configuration. Typically, field data is always mapped to the beginning of the block (offset of 0) and is continguous up to the number of bytes defined by the field device (slave) configuration. The output process data buffer is mapped as buffer 0, while 1 will access the input process data buffer.
The DR_ApReadControl and DR_ApWriteControl functions access the control parameter blocks of the card. Only buffer 2 is valid for CIF cards, which provides access to the protocol parameters. See the Hilscher Fieldbus Card Control API section for details.
The DR_ApReadStatus function accesses the status blocks of the card. Only buffer 2 is valid for CIF cards, which provides master status as well as field device (slave) status and diagnostic information. See the Hilscher Fieldbus Card Status API section for details.