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Philips Semiconductors
3.3 V or 5.0 V Universal Asynchronous
Receiver/Transmitter (UART)
AC CHARACTERISTICS (3.3 VOLT)
V
= 3.3 V
10 %, T
= –40 C to +85 C, unless otherwise specified.
CC
amb
Symbol
Parameter
Reset Timing (See Figure 4)
t
Reset pulse width
RES
5
Bus Timing
(See Figure 5)
t
A0–A3 setup time to RDN, WRN Low
*AS
t
A0–A3 hold time from RDN, WRN low
*AH
t
CEN setup time to RDN, WRN low
*CS
t
CEN Hold time from RDN. WRN low
*CH
t
WRN, RDN pulse width (Low time)
*RW
t
Data valid after RDN low (125pF load. See Figure 3 for smaller loads.)
*DD
t
RDN low to data bus active
*DA
t
Data bus floating after RDN or CEN high
*DF
t
RDN or CEN high to data bus invalid
*DI
t
Data bus setup time before WRN or CEN high (write cycle)
*DS
t
Data hold time after WRN high
*DH
t
High time between read and/or write cycles
*RWD
5
Port Timing
(See Figure 9)
t
Port in setup time before RDN low (Read IP ports cycle)
*PS
t
Port in hold time after RDN high
*PH
t
OP port valid after WRN or CEN high (OPR write cycle)
*PD
Interrupt Timing (See Figure 10)
t
INTRN (or OP3–OP7 when used as interrupts) negated from:
*IR
Read RxFIFO (RxRDY/FFULL interrupt)
Write TxFIFO (TxRDY interrupt)
Reset Command (delta break change interrupt)
Stop C/T command (Counter/timer interrupt)
Read IPCR (delta input port change interrupt)
Write IMR (Clear of change interrupt mask bit(s))
Clock Timing (See Figure 11)
t
X1/CLK high or low time
*CLK
f
X1/CLK frequency
*CLK
f
C/T Clk (IP2) high or low time (C/T external clock input)
*CTC
f
C/T Clk (IP2) frequency
*CTC
t
RxC high or low time (16X)
*RX
RxC Frequency (16X) (for higher speeds contact factory)
f
*RX
RxC Frequency (1x)
t
TxC High or low time (16X)
*TX
f
TxC frequency (16X) (for higher speeds contact factory)
*TX
TxC frequency (1X)
Transmitter Timing, external clock (See Figure 12)
t
TxD output delay from TxC low (TxC input pin)
*TXD
t
Output delay from TxC output pin low to TxD data output
*TCS
2004 Oct 21
1, 2, 3, 4
6
7
5, 7
8
(for higher speeds contact factory)
8
(for higher speeds contact factory)
8, 9
8, 9
14
Product data sheet
SC28L91
Min
Typ
Max
Unit
100
20
ns
10
6
ns
33
ns
0
ns
0
ns
20
10
ns
46
75
ns
0
ns
15
20
ns
0
ns
43
ns
0
–15
ns
27
ns
0
–20
ns
0
–20
ns
50
75
ns
40
79
ns
40
79
ns
40
79
ns
40
79
ns
40
79
ns
40
79
ns
35
25
ns
0.1
3.686
8
MHz
30
15
ns
0
8
MHz
30
10
ns
0
16
MHz
0
1
MHz
30
15
ns
16
MHz
0
1
MHz
40
78
ns
8
30
ns
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