XR88C681_06 Datasheet, PDF (9/101 Pages) Exar Corporation – CMOS Dual Channel UART (DUART)

AC ELECTRICAL CHARACTERISTICS ^{1, 2, 3}
Test Conditions: T_A = 0 - 70°C, V_CC = 5V ¦ 5% unless otherwise specified.
XR88C681
Symbol
Parameter
Min.
Reset Timing (See Figure 51)
t_RES
RESET Pulse Width
1.0
XR88C681 Read and Write Cycle Timing (Figure 52)⁴
t_AS
A0-A3 Setup Time to RD, WR
10
Low
t_AH
A0-A3 Hold Time from RD, WR
0
Low
t_CS
CS Setup Time to RD, WR Low
0
t_CH
CS Hold Time from -RD, -WR
0
High
t_RW
t_DD
t_DF
t_DS
t_DH
t_RWD
-RD, -WR Pulse Width
225
Data Valid from -RD Low
Data Bus Floating from -RD High 10
Data Setup Time to -WR High
100
Data Hold Time from -WR High
5
High Time Between Reads
and/or Writes^{5, 6}
Z-Mode Interrupt Cycle Timing (Figure 53)
t_DIO
IEO Delay Time from IEI
t_IAS
-IACK Setup Time to -RD Low⁷
t_IAH
-IACK Hold Time from -RD High
t_EIS
IEI Setup Time to RD Low
t_EOD
IEO Delay Time from -INTR Low
Port Timing (Figure 54)⁴
t_PS
Port Input Setup Time to
0
-RD/-CS Low
t_PH
Port Input Hold Time from
0
-RD/-CS High
t_PD
Port Output Valid from -WR/-CS
High
Interrupt Output Timing (Figure 55)
t_IR
-INTR or OP3 - OP7 when used
as Interrupts High from: Clear of
Interrupts Status Bits in ISR or
IPCR Clear of Interrupt Mask in
IMR
Clock Timing (Figure 56)
Typ.
60
100
0
50
Max.
175
100
100
100
400
300
300
Unit Conditions
A
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
Rev. 2.11
9