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★ PROGRAMMER'S GUIDE ★ DMA library
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DMA library/2.Reference

2.4 Function specifications

[High level SCU]

 one
 View
 table
 Title
 function specification
 Function
 SCU DMA initialization
 Function name
 DMA_ScuInit
 No
 1
Format
void DMA_ScuMemCopy(void *dst, void *src, Uint32 cnt)
input
none
output
none
function value
none
function
Initialize SCU DMA.
Be sure to do this before executing DMA_ScuCopyMem() and DMA_ScuResult().

 Note
 SCU DMA uses DMA mode 0 transfer end interrupt handling. Therefore, do not change the interrupt mask register for the transfer end interrupt in DMA mode 0. 
 one
 View
 table
 Title
 function specification
 Function
 DMA data transfer
 Function name
 DMA_ScuMemCopy
 No
 2
Format
void DMA_ScuMemCopy(void *dst, void *src, Uint32 cnt)
input
 *dst
 :Destination address
 *src
 : source address
 cnt
 : Number of bytes transferred
output
none
function value
none
function
Performs DMA transfer using SCU's DMA mode 0 direct mode. Please refer to the SCU User's Manual for details. The operation differs depending on whether the destination address is work RAM or other than work RAM. The operation of each is shown below.
The transfer unit is basically a longword, but the source and destination addresses can be specified in bytes. However, if your device requires word boundaries, etc., follow them. Please see the SCU User's Manual for details.
 one
 View
 table
 Title
 function specification
 Function
 Data transfer completion check
 Function name
 DMA_ScuResult
 No
 3
Format
Uint32 DMA_ScuResult(void)
input
none
output
none
function value
Result of DMA_ScuMemCopy()
function
Checks the completion of DMA_ScuMemCopy(). The following values are returned.
Execution result constant name
 constant name
 explanation
 DMA_SCU_END
 normal termination
 DMA_SCU_FAIL
 abnormal termination
 DMA_SCU_BUSY
 Running

remarks
If CPU_Bus is specified as the source or destination in DMA_ScuMemCopy(), the CPU cannot operate while DMA is running. Therefore, the execution result at this time will not be running (DMA_SCU_BUSY).

[High level CPU]

 one
 View
 table
 Title
 function specification
 Function
 Data transfer (in bytes)
 Function name
 DMA_CpuMemCopy1
 No
 4
Format
void DMA_CpuMemCopy1(void *dst, void *src, Uint32 cnt)
input
 *dst
 ;destination address
 *src
 ;source address
 cnt
 ;Transfer count (0-16777215)
 0x00000001 1 time
 0x00ffffff 16777215 times
 0x00000000 16777216 times
output
none
function value
none
function
Transfers byte data from the src address to the dst address cnt times. Transfer amount is cnt bytes. Channel 0, cycle steal mode, transferring without end interrupt. When the destination address is work RAM, the destination area is purged after the transfer to eliminate inconsistencies with the cache. There are no restrictions on addresses.
 one
 View
 table
 Title
 function specification
 Function
 Data transfer (word unit)
 Function name
 DMA_CpuMemCopy2
 No
 5
Format
void DMA_CpuMemCopy2(void *dst, void *src, Uint32 cnt)
input
 *dst
 ;destination address
 *src
 ;source address
 cnt
 ;Transfer count (0-16777215)
 0x00000001 1 time
 0x00ffffff 16777215 times
 0x00000000 16777216 times
output
none
function value
none
function
Transfer word data from src address to dst address cnt times. Transfer amount is cnt*2 bytes. Channel 0, cycle steal mode, transferring without end interrupt. When the destination address is work RAM, the destination area is purged after the transfer to eliminate inconsistencies with the cache. Addresses must be word boundaries.
 one
 View
 table
 Title
 function specification
 Function
 Data transfer (longword unit)
 Function name
 DMA_CpuMemCopy4
 No
 6
Format
void DMA_CpuMemCopy4(void *dst, void *src, Uint32 cnt)
input
 *dst
 ;destination address
 *src
 ;source address
 cnt
 ;Transfer count (0-16777215)
 0x00000001 1 time
 0x00ffffff 16777215 times
 0x00000000 16777216 times
output
none
function value
none
function
Transfers longword data from the src address to the dst address cnt times. Transfer amount is cnt*4 bytes. Channel 0, cycle steal mode, transferring without end interrupt. When the destination address is work RAM, the destination area is purged after the transfer to eliminate inconsistencies with the cache. Addresses must be longword boundaries.
 one
 View
 table
 Title
 function specification
 Function
 Data transfer (16 byte units)
 Function name
 DMA_CpuMemCopy16
 No
 7
Format
void DMA_CpuMemCopy16(void *dst, void *src, Uint32 cnt)
input
 *dst
 ; destination address
 *src
 ; source address
 cnt
 ; Transfer count (0-16777215) (longword unit)
 0x00000001 1 time
 0x00ffffff 16777215 times
 0x00000000 16777216 times
output
none
function value
none
function
Transfers longword data from the src address to the dst address cnt times. Transfer amount is cnt x 4 bytes. Channel 0, cycle steal mode, transferring without end interrupt. When the destination address is work RAM, the destination area is purged after the transfer to eliminate inconsistencies with the cache. Addresses must be longword boundaries.
 one
 View
 table
 Title
 function specification
 Function
 Data transfer completion check
 Function name
 DMA_CpuResult
 No
 8
Format
Uint32 DMA_CpuResult(void)
input
none
output
none
function value
Result of DMA_CpuMemCopy1,2,4,16()
function
Check the completion of DMA_CpuMemCopy1,2,4,16(). The following values are returned.
Execution result constant name
 constant name
 explanation
 DMA_CPU_END
 normal termination
 DMA_CPU_BUSY
 Running

[Low level SCU]

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 View
 table
 Title
 function specification
 Function
 DMA transfer parameter settings
 Function name
 DMA_ScuSetPrm
 No
 9
Format
void DMA_ScuSetPrm(DmaScuPrm *prm, Uint32 ch)
input
 prm
 :Transfer parameters
 ch
 :DMA channel
output
none
function value
none
function
Sets the transfer parameter values for the specified DMA channel.
 one
 View
 table
 Title
 function specification
 Function
 DMA transfer start
 Function name
 DMA_ScuStart
 No
 10
Format
void DMA_ScuStart(Uint32 ch)
input
ch: DMA channel
output
none
function value
none
function
Starts a DMA transfer on the specified DMA channel.
 one
 View
 table
 Title
 function specification
 Function
 Get DMA status
 Function name
 DMA_ScuGetStatus
 No
 11
Format
void DMA_ScuGetStatus(DmaScuStatus *status,Uint32 ch)
input
ch: input channel
output
status: status pointer
function value
none
function
Gets the status of the specified DMA channel.
!!Note!!
The members of the DmaScuStatus structure, dxbk (DMA suspended flag) and dxwt (DMA waiting flag), have been deleted.

[Low level CPU]

 one
 View
 table
 Title
 function specification
 Function
 DMA common transfer parameter settings
 Function name
 DMA_CpuSetComPrm
 No
 12
Format
void DMA_CpuSetComPrm(DmaCpuComPrm *com_prm)
input
com_prm: Common transfer parameters
output
none
function value
none
function
Sets the specified common transfer parameters. However, parameters masked by DmaCpuComPrm.msk are not set.
remarks
If DMA_CPU_M_AE was not masked in DmaCpuComPrm.msk, clear the address error flag. If you did not mask DMA_CPU_M_NMIF, clear the NMI flag.
 one
 View
 table
 Title
 function specification
 Function
 DMA transfer parameter settings
 Function name
 DMA_CpuSetPrm
 No
 13
Format
void DMA_CpuSetPrm(DmaCpuPrm *prm Uint32 ch)
input
 prm
 :Transfer parameters
 ch
 :DMA channel
output
none
function value
none
function
Sets transfer parameters to the specified DMA channel. However, parameters masked by DmaCpuPrm.msk are not set.
remarks
If you did not mask DMA_CPU_TE in DmaCpuPrm.msk, clear the transfer end flag bit.
 one
 View
 table
 Title
 function specification
 Function
 DMA transfer start
 Function name
 DMA_CpuStart
 No
 14
Format
Uint32 DMA_CpuStart(Uint32 ch)
input
ch: DMA channel
output
none
function value
none
function
Starts a DMA transfer on the specified DMA channel.
 one
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 table
 Title
 function specification
 Function
 DMA transfer aborted
 Function name
 DMA_CpuStop
 No
 15
Format
void DMA_CpuStop(Uint32 ch)
input
ch: DMA channel
output
none
function value
none
function
Terminates DMA transfer for the specified DMA channel.
 one
 View
 table
 Title
 function specification
 Function
 DMA all channel transfer cancellation
 Function name
 DMA_CpuAllStop
 No
 16
Format
void DMA_CpuAllStop(void)
input
none
output
none
function value
none
function
Aborts DMA transfers for all DMA channels.
 one
 View
 table
 Title
 function specification
 Function
 DMA common status acquisition
 Function name
 DMA_CpuGetComStatus
 No
 17
Format
void DMA_CpuGetComStatus(DmaCpuComStatus *status)
input
none
output
status: status pointer
function value
none
function
Gets the specified common status.
 one
 View
 table
 Title
 function specification
 Function
 Get DMA status
 Function name
 DMA_CpuGetStatus
 No
 18
Format
void DMA_CpuGetStatus(DmaCpuStatus *status, Uint32 ch)
input
ch: DMA channel
output
status: status pointer
function value
none
function
Gets the status of the specified DMA channel.
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★ PROGRAMMER'S GUIDE ★ DMA library
Copyright SEGA ENTERPRISES, LTD., 1997