Task Overview - Task Direct Memory Access (DMA) low level driver Task Overview - Library The DMA task and associated library calls, handles read/write of higher speed devices. Task Attributes Task priority : 128 (normal priority) Task depends on : Tasks/OS/Library/OS.a Task Description This task controls the DMA hardware, allowing controlling tasks to instruct DMA operations. Library Description To be written. Task History        05 February 2009 GJP Created  06 May 2009 GJP DMA for channel 2 (Floppy) works  10 July 2009 GJP Support all ISA DMA channels       Task Function Calls Here follows a list of functions supplied by this library with a brief description of each. By clicking on a function name, further information will be shown. Function Brief Lib_DMASetup Initialise a DMA channel prior to data transfer Lib_DMAStart Commence a DMA read or write transfer Lib_DMAStop Stops an existing or recently completed DMA transfer Lib_DMASetup Initialise a DMA channel prior to data transfer Function prototype  BOOL Lib_DMASetup(                     BYTE channel,                     BYTE *buffer,                     DWORD size  ); Input parameter(s)      BYTE channel - DMA channel to stop  void *buffer - address of DMA buffer in memory  DWORD size - size of transfer in bytes     Return value      BOOL - completion status     Purpose Each DMA channel needs to be initialised prior to data transfer, with the source/destination address and data size in bytes. Both 8 and 16 bit transfers are permitted but note that a transfer size must be a multiple of the transfer size (eg. 16 bit transfers must be a multiple of 2 bytes). History        26 June 2009 GJP Created       Click here to report an error Back to top Lib_DMAStart Commence a DMA read or write transfer Function prototype  BOOL Lib_DMAStart(                     BYTE channel,                     DWORD mode,                     BOOL rnw  ); Input parameter(s)      BYTE channel - DMA channel to stop  DWORD mode - DMA transfer type  BOOL - read or not-write     Return value      BOOL - completion status     Purpose Starts a DMA transfer, for read or write operations. Control is returned immediately to caller and the DMA transfer will continue in the background. The transfer type (read/write) and method (single, demand etc) is specified in this call. History        05 February 2009 GJP Created       Click here to report an error Back to top Lib_DMAStop Stops an existing or recently completed DMA transfer Function prototype  BOOL Lib_DMAStop(                    BYTE channel  ); Input parameter(s)      BYTE channel - DMA channel to stop     Return value      BOOL - completion status     Purpose This is to be called when the DMA transfer is complete or when a transfer has failed (such as hardware error). History        05 May 2009 GJP Created       Click here to report an error Back to top

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