
Hardware Description
MFC 2000 Multifunctional Peripheral Controller 2000
100723A
Conexant
17-13
Output data FIFO Control Register for the data to the external memory (the forward direction)
(for DMA channel 11):
Address:
Bit 15
Bit 14
Bit 13
Bit 12
Bit 11
Bit 10
Bit 9
Bit 8
Default:
Parallel Port Output
Data FIFO Control
Register
(PIOOutFIFOCtrl)
$01FF822B
Address:
FIFO
Enabled
(R)
Data
Request
(R)
FIFO
Ready
(R)
FIFO DMA Threshold
FIFO Output Pointer
Rst Value
00h
Read Value
00h
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Default:
Parallel Port Output
Data FIFO Control
Register
(PIOOutFIFOCtrl)
$01FF822A
(Not Used)
Holding
Register Full
Byte Present FIFO Data Quantity
FIFO Input Pointer
Rst Value
x0000000b
Read Value
00h
Bit 15:
This bit indicates that the FIFO is active and capable of generating
DMA requests. This bit generally follows the setting of the LCL_ENB
input signal except the FIFO Enabled register bit will remain asserted
if the LCL_ENB input signal is set to false while the FIFO is executing
a DMA transfer. In this case, the register bit will remain set for the
duration of the DMA transfer and then become cleared.
This bit is similar to the DMA_REQ signal except that it is not blocked
when DMA_TC0 is set. It indicates that the programmed threshold has
been met or exceeded and that the FIFO requires data transfers either
by enabling hardware DMA through DMA_TC0 or by executing
software DMA cycles.
This bit indicates that the FIFO can accept data transfers to/from the
local logic. This bit is low when the data direction is into the local logic
and the FIFO is empty or when the data direction is out of the local
logic and the FIFO is full.
This bit field indicates at which point the FIFO should issue a DMA
request. It is compared with the FIFO Data Quantity bit field to
determine when this should occur. Legal values are from 1 to 4. A
value of zero causes no data transfers to occur. Values greater than 4
are treated as 4.
This bit field indicates which byte of the FIFO quad halfword structure
is the next to be used as output data.
Not used
This bit indicates that there is a full word in the holding register.
This bit indicates that there is a single byte in the holding register.
This bit field indicates the number of quad halfwords that contain data.
Valid values are from 0 to 4.
This bit field indicates which byte of the FIFO quad halfword structure
is the next to receive input data.
Bit 14:
Bit 13:
Bit 12-10:
Bit 9-8:
Bit 7:
Bit 6:
Bit 5:
Bit 4-2:
Bit 1-0:
Note:
It is strongly recommended that the FIFO be disabled before firmware writes to the FIFO
Control register. The FIFO Control register contains data that is essential to the FIFO’s
operation. If this data is changed while the FIFO is operating, unpredictable operation will result.