TransDimension Inc.
Interfacing OTG243 to Motorola MCF5272 ColdFire Processor
This pin should be left floating if external 1.5KΩ pull-up resistor is not used.
OverCurrent: /OC
It is recommended to add an external pull-up for OverCurrent signal.
Power On: /PO
This ganged power-on signal is an output, so it is OK to leave it floating if not used.
However, do not use pull-up resistor if this signal is used in a low power application. If OTG243
is put into power-save mode with /PO signal asserted, there will be unnecessary current leakage
through this pull-up resistor.
2.4 Software Configuration
Bus Cycle Timing
Bus cycle timing parameters for the OTG243 read/write operation are listed below. The OTG243
register read and register write cycles are illustrated in Figures 5 and 6, respectively.
Symbol
tRPW
tWPW
tACR
tASL
tAHH
tDSW
tDVR
tDHR
tDHW
tCRWL
tRWCH
Parameter
/RD pulse width
/WR pulse width
Access cycle recovery time
Address setup time before /RD or /WR goes low
Address hold time after /RD or /WR high
Data setup time before /WR high
Data valid time after /RD low
Data hold time after /RD high
Data hold time after /WR high
/CS low to /RD or /WR low
/RD or /WR high to /CS high
Min
Max Unit
55
ns
55
ns
25
ns
0
ns
0
ns
45
ns
55
ns
3
ns
0
ns
0
ns
0
ns
Figure 4: OTG243 bus cycle timing parameters
6