Samsung S3C6400X User Manual page 794

S3C6400X RISC MICROPROCESSOR
Status Register (STAT)
BSEL [3:0] = 0000, MP_A[1:0] = 10, R, Reset value = 0x90A2
Field
WRITABLE_CNT
WFIFO_PEMPTY
Reserved
WFIFO
RFIFO
Bit
[15:8] Writable word counts in wfifo: Read only
This field shows how many words can be written into WFIFO
without checking of the WFIFO fullness. For example, if this field
is 0x08, there are currently 16 (8 x 2) entries of wfifo so that the
CPU can write 16 words immediately.
Note that the reset value is 0x90 so that 288 words can be
written without overflow. Practically, since the packet head and
address must be written into WFIFO, the recommend maximum
data payload size is 256-word.
[7] WFIFO partial empty flag (from CPUIF_CLIENT itself)
This flag becomes 1 when the number of empty elements in
WFIFO is larger than or equal to a threshold (ie, 2 x INTE
[15:8] ).
[6:2] -
[1] WFIFO empty flag. (from CPUIF_CLIENT itself)
This flag becomes 1 when Write Buffer is empty so that the
maximum capacity of Write Buffer is available right now. At least
a single write into wfifo resets this flag.
[0] RFIFO ready flag (from CPUIF_CLIENT itself)
This flag becomes 1 when Read Buffer is ready to read. The
CPU read of DATAH resets this flag.
Preliminary product information describe products that are in development,
for which full characterization data and associated errata are not yet available.
Specifications and information herein are subject to change without notice.
Description
HOST INTERFACE
Initial State
0x90
1
0
1
0
24-17