TL16C554 Datasheet, PDF (5/33 Pages) Texas Instruments – ASYNCHRONOUS COMMUNICATIONS ELEMENT

TL16C554, TL16C554I
ASYNCHRONOUS COMMUNICATIONS ELEMENT
SLLS165D – JANUARY 1994 – REVISED JULY 1998
Terminal Functions (Continued)
TERMINAL
NAME
FN
NO.
PN ^I/O
NO.
DESCRIPTION
INTA, INTB,
INTC, INTD
15, 21, 27, 34, O External interrupt output. The INTx outputs go high (when enabled by the interrupt register) and
49, 55 67, 74
inform the CPU that the ACE has an interrupt to be serviced. Four conditions that cause an interrupt
to be issued are: a receiver error, receiver data available or timeout (FIFO mode only), transmitter
holding register empty, and an enabled modem status interrupt. The interrupt is disabled when it is
serviced or as the result of a master reset.
IOR
52
70
I Read strobe. A low level on IOR transfers the contents of the TL16C554 data bus to the external CPU
bus.
IOW
18
31
I Write strobe. IOW allows the CPU to write into the selected address by the address register.
RESET
37
53
I Master reset. When active, RESET clears most ACE registers and sets the state of various signals.
The transmitter output and the receiver input is disabled during reset time.
RIA, RIB,
RIC, RID
8, 28, 18, 43, I Ring detect indicator. A low on RIx indicates the modem has received a ring signal from the telephone
42, 62 58, 3
line. The condition of this signal can be checked by reading bit 6 of the modem status register.
RTSA, RTSB,
RTSC, RTSD
14, 22, 26, 35, O Request to send. When active, RTSx informs the modem or data set that the ACE is ready to receive
48, 56 66, 75
data. Writing a 1 in the modem control register sets this bit to a low state. After reset, this terminal
is set high. These terminals have no affect on the transmit or receive operation.
RXA, RXB
RXC, RXD
7, 29, 17, 44, I Serial input. RXx is a serial data input from a connected communications device. During loopback
41, 63 57, 4
mode, the RXx input is disabled from external connection and connected to the TXx output internally.
RXRDY
38
54 O Receive ready. RXRDY goes low when the receive FIFO is full. It can be used as a single transfer
or multitransfer.
TXA, TXB
TXC, TXD
17, 19, 29, 32, O Transmit outputs. TXx is a composite serial data output that is connected to a communications
51, 53 69, 72
device. TXA, TXB, TXC, and TXD are set to the marking (high) state as a result of reset.
TXRDY
39
55 O Transmit ready. TXRDY goes low when the transmit FIFO is full. It can be used as a single transfer
or multitransfer function.
VCC
13, 30, 5, 25,
47, 64 45, 65
Power supply
XTAL1
35
50
I Crystal input 1 or external clock input. A crystal can be connected to XTAL1 and XTAL2 to utilize the
internal oscillator circuit. An external clock can be connected to drive the internal clock circuits.
XTAL2
36
51 O Crystal output 2 or buffered clock output (see XTAL1).
absolute maximum ratings over free-air temperature range (unless otherwise noted)^†
Supply voltage range, V_CC (see Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 0.5 V to 7 V
Input voltage range at any input, V_I . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 0.5 V to 7 V
Output voltage range, V_O . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 0.5 V to V_CC + 3 V
Continuous total power dissipation at (or below) 70°C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 500 mW
Operating free-air temperature range, T_A: TL16C554 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 0°C to 70°C
TL16C554I . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –40°C to 85°C
Storage temperature range, T_stg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 65°C to 150°C
† _{Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, and}
functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not
implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
NOTE 1: All voltage levels are with respect to GND.
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