
Hardware Description
MFC 2000 Multifunctional Peripheral Controller 2000
100723A
Conexant
4-87
Address:ch4csbs
DMAUSB Transfer
Block Size Reg.
(DMAUSBBlockSize
)
Address:ch4csbs
DMAUSBTransfer
Block Size Reg.
(DMAUSBBlockSize
)
Bit 15
USB Channel
Enable = 1
Bit 14
Stop At
Block
Bit 13
Upper six bits of the Block Size Counter
Bit 12
Bit 11
Bit 10
Bit 9
Bit 8
Default:
Rst.
Value
00h
Read
Value 00h
Default:
Rst. Value
00h
Read
Value 00h
Bit 7
Low Byte Value for USB Memory Block Size Counter
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Block Size data written to this register will be placed into the inactive Block Size register. This register will become
active once the prior block has completed (USB IRQ).
Reading this register will return the Block Size value when
the last USBACK occurred. Writing to this will initialize the logical channel. Therefore, when setting up a logical
channel, this register should be written to last.
Note
: This register is double buffered. Writing to this location twice will load the active register
as well as the buffer register. Upon a block limit interrupt, the buffer value will be activated
therefor a new buffered value should be written to this register.
DMA USB Channel Block Size Limit Counter
DMAUSB0 BlkSiz
01FF81CC-CD
DMAUSB1 BlkSiz
01FF81D2-D3
DMAUSB2 BlkSiz
01FF81D8-D9
DMAUSB3 BlkSiz
01FF81DE-DF
Bits [13:0] DMAUSB Memory Block Size
The block size of DMA channel can range from 1 – 16383 DMA
transfers.
The Block Size counter will decrement regardless of the DMA Address
counter’s activity. The block size register content is 0000h when the
block size limit is reached.
When the block size reaches its limit, an IRQ will be generated upon
the next Channel ACK.
Writing To this register will clear the IRQ.
Bit 14 Note
:
is entered.
When this bit is set, the DMA channel will disable it’s self until a new block size
If this bit is 0, when a block limit is reached the next block size will be downloaded into the
counter along with the next DMA address and transfers will continue within the new block. Upon
the next channel ACK, an IRQ will be generated.
Bit 15:
This bit must be set at all times to enable the channel and is not part
of the double buffering process.