
Philips Semiconductors
SC16C554/554D
Quad UART with 16-byte FIFO and infrared (IrDA) encoder/decoder
Product data
Rev. 05 — 10 May 2004
11 of 55
9397 750 13132
Koninklijke Philips Electronics N.V. 2004. All rights reserved.
IOW
18
9
31
I
Input/Output Write strobe (Active-LOW).
This function is
associated with the 16 mode only. A logic 0 transition on this pin will
transfer the contents of the data bus (D0-D7) from the external CPU
to an internal register that is defined by address bits A0-A2. When
the 68 mode is selected, this pin functions as R/W (see definition
under R/W).
Interrupt Request or Interrupt ‘A’.
This function is associated with
the 68 mode only. In the 68 mode, interrupts from UART channels
A-D are wire-ORed internally to function as a single IRQ interrupt.
This pin transitions to a logic 0 (if enabled by the interrupt enable
register) whenever a UART channel(s) requires service. Individual
channel interrupt status can be determined by addressing each
channel through its associated internal register, using CS and A3-A4.
In the 68 mode, and external pull-up resistor must be connected
between this pin and V
CC
. The function of this pin changes to INTA
when operating in the 16 mode (see definition under INTA).
Not connected.
IRQ
15
-
-
O
n.c.
21, 49,
52, 54,
55, 65
-
1, 10,
20, 21,
30, 40,
41, 49,
52, 60,
61, 71,
80
53
-
RESET
(RESET)
37
27
I
Reset.
In the 16 mode, a logic 1 on this pin will reset the internal
registers and all the outputs. The UART transmitter output and the
receiver input will be disabled during reset time. (See
Section 7.11
“SC16C554/554D external reset conditions”
for initialization details.)
When 16/68 is a logic 0 (68 mode), this pin functions similarly, but as
an inverted reset interface signal, RESET.
Ring Indicator (Active-LOW).
These inputs are associated with
individual UART channels, A through D. A logic 0 on this pin indicates
the modem has received a ringing signal from the telephone line. A
logic 1 transition on this input pin will generate an interrupt.
Request to Send (Active-LOW).
These outputs are associated with
individual UART channels, A through D. A logic 0 on the RTS pin
indicates the transmitter has data ready and waiting to send. Writing
a logic 1 in the modem control register MCR[1] will set this pin to a
logic 0, indicating data is available. After a reset this pin will be set to
a logic 1. This pin only affects the transmit and receive operations
when Auto RTS function is enabled via the Enhanced Feature
Register (EFR[6]) for hardware flow control operation.
Read/Write strobe.
This function is associated with the 68 mode
only. This pin provides the combined functions for Read or Write
strobes.
Logic 1 = Read from UART register selected by CS and A0-A4.
Logic 0 = Write to UART register selected by CS and A0-A4.
RIA, RIB,
RIC, RID
8, 28,
42, 62
63, 19,
30, 50
18, 43,
58, 3
I
RTSA,RTSB,
RTSC, RTSD
14, 22,
48, 56
5, 13,
36, 44
26, 35,
66, 75
O
R/W
18
-
-
I
Table 2:
Pin description
…continued
Pin
PLCC68 LQFP64 LQFP80
Symbol
Type
Description