Designing Hardware for QuickUSB
Slave245 I/O Model
The Slave245 I/O Model allows QuickUSB to duplicate the functionality of the
FTDI245BM I/O waveforms with a speed increase of up to 10X. This I/O model
is implemented in the QuickUSB firmware file ‘quickusb-245 vX.XX.qusb’ where
X.XX is the firmware version number. The following QuickUSB I/O connections
are used for 245BM targets:
QuickUSB Signal
245BM Signal
RDY0 (nSLRD) & PA2 (SLOE)
RD#
RDY1 (nSLWR) & PA5 (FIFOADR1)
WR
CTL2 (FLAGC)
RXF#
CTL1 (FLAGB )
TXE#
PB0 D0
PB1 D1
PB2 D2
PB3 D3
PB4 D4
PB5 D5
PB6 D6
PB7 D7
Figure 3 - QuickUSB to 245BM Connection Table
X
t
RDpwl
Read Cycle
Data0
t
XFDRD
t
RDpwh
Data1
Data2
t
XFLG
RD/SLOE
RDY0/PA2
WR/FIFOADR[1] RDY1/PA5
TXE
CTL2
RXF
CTL1
FD[7:0]
PB[7:0]
Name
PIN
X
X
Signifies QuickUSB Write to the Data Bus
t
XFDRD
X
X
t
ADRFLG
X
t
WRpwl
RD/SLOE
RDY0/PA2
WR/FIFOADR[1] RDY1/PA5
TXE
CTL2
RXF
CTL1
FD[7:0]
PB[7:0]
Name
PIN
Z
Write Cycle
Data0
t
SFD
t
WRpwh
t
FDH
Z
Data1
Z
Data2
t
XFLG
Z
Signifies QuickUSB Read from the Data Bus
X
Figure 4 - Slave245 I/O Model Timing Diagrams
Parameter
Description
Min
Max
Unit
tRDpwl
SLRD Pulse Width Low
50
ns
tRDpwh
SLRD Pulse Width High
50
ns
tWRpwl
SLWR Pulse Width Low
50
ns
tWRpwh
SLWR Pulse Width High
70
ns
tSFD
SLWR to FIFO DATA Set-up Time
10
ns
tFDH
FIFO DATA to SLWR Hold Time
10
ns
tXFLG
SLRD/SLWR to Flags Output Propagation Delay
70 ns
tADRFLG
SLWR/FIFOADR[1] to Flags Output Propagation
Delay
10.7
ns
tXFDRD
SLRD to FIFO Data Output Propagation Delay
15 ns
Figure 5 - Slave245 I/O Model Timing Parameters
20
High Speed Parallel Port
