W90221X Winbond Electronics Corp America, W90221X Datasheet - Page 148

• Manufacturer Part Number: W90221X
• Description: Pa-risc Embedded Controller
• Manufacturer: Winbond Electronics Corp America

FIFO Status Register (FSR)
Port address: 0xf000037b
Bits 0-4
Bit 5
Bit 6
Bit 3
W90221X version 0.6
0
0
1
0
1
0
1
1
FIFO valid bytes
Valid bytes in device data FIFO (DFIFO)
During forward transferring, these bits indicate how many bytes in 16-
byte register DFIFO are still not transferred yet. While during reverse
transferring, these bits indicate the number of data bytes that are
received from the parallel port interface and not read by CPU core.
DFIFO data available
DFIFO contains data bytes less than one “ Pword”
DFIFO contains at least one valid “ Pword”
DFIFO space available
DFIFO contains empty locations less than one “ Pword”
DFIFO contains at least one empty “ Pword” location
DFIFO over/under run
DFIFO is not yet over/under run
DFIFO is already over/under run (Once this bit is set, it will remain set
until DFIFO or the PPI is reset)
2
Access type: read
3
4
DA
5
SA
6
Default: 0x---
OV
7
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