Data Sheet

SC16IS741
Single UART with I2C-bus/SPI interface, 64 bytes of transmit
and receive FIFOs, IrDA SIR built-in support
Rev. 01 — 29 April 2010
Product data sheet
1. General description
The SC16IS741 is a slave I2C-bus/SPI interface to a single-channel high performance
UART. It offers data rates up to 5 Mbit/s and guarantees low operating and sleeping
current. The device comes in the TSSOP16 package, which makes it ideally suitable for
handheld, battery operated applications. This device enables seamless protocol
conversion from I2C-bus or SPI to and RS-232/RS-485 and are fully bidirectional.
The SC16IS741’s internal register set is backward-compatible with the widely used and
widely popular 16C450. This allows the software to be easily written or ported from
another platform.
The SC16IS741 also provides additional advanced features such as auto hardware and
software flow control, automatic RS-485 support, and software reset. This allows the
software to reset the UART at any moment, independent of the hardware reset signal.
2. Features
2.1 General features
„
„
„
„
„
„
„
„
„
„
„
„
„
„
„
„
„
„
Single full-duplex UART
Selectable I2C-bus or SPI interface
3.3 V or 2.5 V operation
Industrial temperature range: −40 °C to +95 °C
64 bytes FIFO (transmitter and receiver)
Fully compatible with industrial standard 16C450 and equivalent
Baud rates up to 5 Mbit/s in 16× clock mode
Auto hardware flow control using RTS/CTS
Auto software flow control with programmable Xon/Xoff characters
Single or double Xon/Xoff characters
Automatic RS-485 support (automatic slave address detection)
RS-485 driver direction control via RTS signal
RS-485 driver direction control inversion
Built-in IrDA encoder and decoder interface
Software reset
Transmitter and receiver can be enabled/disabled independent of each other
Receive and Transmit FIFO levels
Programmable special character detection
SC16IS741
NXP Semiconductors
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
„ Fully programmable character formatting
‹ 5-bit, 6-bit, 7-bit or 8-bit character
‹ Even, odd, or no parity
‹ 1, 11⁄2, or 2 stop bits
„ Line break generation and detection
„ Internal Loopback mode
„ Sleep current less than 30 μA at 3.3 V
„ Industrial and commercial temperature ranges
„ Available in the TSSOP16 package
2.2 I2C-bus features
„
„
„
„
Noise filter on SCL/SDA inputs
400 kbit/s maximum speed
Compliant with I2C-bus fast speed
Slave mode only
2.3 SPI features
„ Slave mode only
„ SPI Mode 0
3. Applications
„ Factory automation and process control
„ Portable and battery operated devices
„ Cellular data devices
4. Ordering information
Table 1.
Ordering information
Type number
SC16IS741IPW
Package
Name
Description
Version
TSSOP16
plastic thin shrink small outline package; 16 leads; body width 4.4 mm
SOT403-1
SC16IS741_1
Product data sheet
© NXP B.V. 2010. All rights reserved.
Rev. 01 — 29 April 2010
2 of 52
SC16IS741
NXP Semiconductors
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
5. Block diagram
VDD
SC16IS741
RESET
SCL
16C450
COMPATIBLE
REGISTER
SETS
SDA
A0
I2C-BUS
A1
TX
RX
RTS
CTS
IRQ
1 kΩ (3.3 V)
1.5 kΩ (2.5 V)
VDD
VDD
I2C/SPI
XTAL1
Fig 1.
XTAL2
VSS
002aaf155
Block diagram of SC16IS741 I2C-bus interface
VDD
SC16IS741
RESET
SCLK
16C450
COMPATIBLE
REGISTER
SETS
CS
SO
SPI
SI
TX
RX
RTS
CTS
IRQ
1 kΩ (3.3 V)
1.5 kΩ (2.5 V)
VDD
I2C/SPI
XTAL1
Fig 2.
XTAL2
002aaf157
Block diagram of SC16IS741 SPI interface
SC16IS741_1
Product data sheet
VSS
© NXP B.V. 2010. All rights reserved.
Rev. 01 — 29 April 2010
3 of 52
SC16IS741
NXP Semiconductors
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
6. Pinning information
6.1 Pinning
VDD
1
16 XTAL2
VDD
1
16 XTAL2
A0
2
15 XTAL1
CS
2
15 XTAL1
A1
3
14 RESET
SI
3
14 RESET
n.c.
4
13 RX
SO
4
SCL
5
12 TX
SCLK
5
SDA
6
11 CTS
VSS
6
11 CTS
IRQ
7
10 RTS
IRQ
7
10 RTS
I2C
8
SPI
8
SC16IS741IPW
9
VSS
SC16IS741IPW
002aaf158
a. I2C-bus interface
Fig 3.
13 RX
12 TX
9
VSS
002aaf159
b. SPI interface
Pin configuration for TSSOP16
6.2 Pin description
Table 2.
Symbol
Pin description
Pin
Type Description
VDD
1
-
power supply
CS/A0
2
I
SPI chip select or I2C-bus device address select A0. If SPI
configuration is selected by I2C/SPI pin, this pin is the SPI chip select
pin (Schmitt-trigger, active LOW). If I2C-bus configuration is selected
by I2C/SPI pin, this pin along with A1 pin allows user to change the
device’s base address.
SI/A1
3
I
SPI data input pin or I2C-bus device address select A1. If SPI
configuration is selected by I2C/SPI pin, this is the SPI data input pin.
If I2C-bus configuration is selected by I2C/SPI pin, this pin along with
A0 pin allows user to change the device’s base address. To select the
device address, please refer to Table 28.
SO
4
O
SPI data output pin. If SPI configuration is selected by I2C/SPI pin,
this is a 3-stateable output pin. If I2C-bus configuration is selected by
I2C/SPI pin, this pin function is undefined and must be left as n.c. (not
connected).
SCL/SCLK
5
I
I2C-bus or SPI input clock.
SDA
6
I/O
I2C-bus data input/output, open-drain if I2C-bus configuration is
selected by I2C/SPI pin. If SPI configuration is selected then this pin
is an undefined pin and must be connected to VSS.
IRQ
7
O
Interrupt (open-drain, active LOW). Interrupt is enabled when
interrupt sources are enabled in the Interrupt Enable Register (IER).
Interrupt conditions include: change of state of the input pins, receiver
errors, available receiver buffer data, available transmit buffer space,
or when a modem status flag is detected. An external resistor (1 kΩ
for 3.3 V, 1.5 kΩ for 2.5 V) must be connected between this pin and
VDD.
I2C/SPI
8
I
I2C-bus or SPI interface select. I2C-bus interface is selected if this pin
is at logic HIGH. SPI interface is selected if this pin is at logic LOW.
SC16IS741_1
Product data sheet
© NXP B.V. 2010. All rights reserved.
Rev. 01 — 29 April 2010
4 of 52
SC16IS741
NXP Semiconductors
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
Table 2.
Pin description …continued
Symbol
Pin
Type Description
VSS
9
-
ground
RTS
10
O
UART request to send (active LOW). 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 is 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.
CTS
11
I
UART clear to send (active LOW). A logic 0 (LOW) on the CTS pin
indicates the modem or data set is ready to accept transmit data from
the SC16IS741. Status can be tested by reading MSR[4]. This pin
only affects the transmit and receive operations when auto CTS
function is enabled via the Enhanced Feature Register EFR[7] for
hardware flow control operation.
TX
12
O
UART transmitter output. During the local Loopback mode, the TX
output pin is disabled and TX data is internally connected to the
UART RX input.
RX
13
I
UART receiver input. During the local Loopback mode, the RX input
pin is disabled and TX data is connected to the UART RX input
internally.
RESET
14
I
device hardware reset (active LOW)[1]
XTAL1
15
I
Crystal input or external clock input. Functions as a crystal input or as
an external clock input. A crystal can be connected between XTAL1
and XTAL2 to form an internal oscillator circuit (see Figure 11).
Alternatively, an external clock can be connected to this pin.
XTAL2
16
O
Crystal output or clock output. (See also XTAL1.) XTAL2 is used as a
crystal oscillator output.
[1]
See Section 7.4 “Hardware reset, Power-On Reset (POR) and software reset”
7. Functional description
The UART will perform serial-to-I2C conversion on data characters received from
peripheral devices or modems, and I2C-to-serial conversion on data characters
transmitted by the host. The complete status the SC16IS741 UART can be read at any
time during functional operation by the host.
The SC16IS741 can be placed in an alternate mode (FIFO mode) relieving the host of
excessive software overhead by buffering received/transmitted characters. Both the
receiver and transmitter FIFOs can store up to 64 characters (including three additional
bits of error status per character for the receiver FIFO) and have selectable or
programmable trigger levels.
The SC16IS741 has selectable hardware flow control and software flow control. Hardware
flow control significantly reduces software overhead and increases system efficiency by
automatically controlling serial data flow using the RTS output and CTS input signals.
Software flow control automatically controls data flow by using programmable Xon/Xoff
characters.
The UART includes a programmable baud rate generator that can divide the timing
reference clock input by a divisor between 1 and (216 – 1).
SC16IS741_1
Product data sheet
© NXP B.V. 2010. All rights reserved.
Rev. 01 — 29 April 2010
5 of 52
SC16IS741
NXP Semiconductors
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
7.1 Trigger levels
The SC16IS741 provides independently selectable and programmable trigger levels for
both receiver and transmitter interrupt generation. After reset, both transmitter and
receiver FIFOs are disabled and so, in effect, the trigger level is the default value of one
character. The selectable trigger levels are available via the FCR. The programmable
trigger levels are available via the TLR. If TLR bits are cleared then selectable trigger level
in FCR is used. If TLR bits are not cleared then programmable trigger level in TLR is used.
7.2 Hardware flow control
Hardware flow control is comprised of auto CTS and auto RTS (see Figure 4). Auto CTS
and auto RTS can be enabled/disabled independently by programming EFR[7:6].
With auto CTS, CTS must be active before the UART can transmit data.
Auto RTS only activates the RTS output when there is enough room in the FIFO to receive
data and de-activates the RTS output when the RX FIFO is sufficiently full. The halt and
resume trigger levels in the TCR determine the levels at which RTS is
activated/deactivated. If TCR bits are cleared then selectable trigger levels in FCR are
used in place of TCR.
If both auto CTS and auto RTS are enabled, when RTS is connected to CTS, data
transmission does not occur unless the receiver FIFO has empty space. Thus, overrun
errors are eliminated during hardware flow control. If not enabled, overrun errors occur if
the transmit data rate exceeds the receive FIFO servicing latency.
UART 1
SERIAL TO
PARALLEL
UART 2
RX
TX
PARALLEL
TO SERIAL
RX
FIFO
TX
FIFO
FLOW
CONTROL
RTS
PARALLEL
TO SERIAL
TX
CTS
RX
FLOW
CONTROL
SERIAL TO
PARALLEL
TX
FIFO
RX
FIFO
FLOW
CONTROL
CTS
RTS
FLOW
CONTROL
002aab656
Fig 4.
Autoflow control (auto RTS and auto CTS) example
SC16IS741_1
Product data sheet
© NXP B.V. 2010. All rights reserved.
Rev. 01 — 29 April 2010
6 of 52
SC16IS741
NXP Semiconductors
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
7.2.1 Auto RTS
Figure 5 shows RTS functional timing. The receiver FIFO trigger levels used in auto RTS
are stored in the TCR or FCR. RTS is active if the RX FIFO level is below the halt trigger
level in TCR[3:0]. When the receiver FIFO halt trigger level is reached, RTS is deasserted.
The sending device (for example, another UART) may send an additional character after
the trigger level is reached (assuming the sending UART has another character to send)
because it may not recognize the deassertion of RTS until it has begun sending the
additional character. RTS is automatically reasserted once the receiver FIFO reaches the
resume trigger level programmed via TCR[7:4]. This re-assertion allows the sending
device to resume transmission.
RX
start
character
N
stop
start
character
N+1
stop
start
RTS
receive
FIFO
read
1
2
N
N+1
002aab040
(1) N = receiver FIFO trigger level.
(2) The two blocks in dashed lines cover the case where an additional character is sent, as described in Section 7.2.1
Fig 5.
RTS functional timing
7.2.2 Auto CTS
Figure 6 shows CTS functional timing. The transmitter circuitry checks CTS before
sending the next data byte. When CTS is active, the transmitter sends the next byte. To
stop the transmitter from sending the following byte, CTS must be deasserted before the
middle of the last stop bit that is currently being sent. The auto CTS function reduces
interrupts to the host system. When flow control is enabled, CTS level changes do not
trigger host interrupts because the device automatically controls its own transmitter.
Without auto CTS, the transmitter sends any data present in the transmit FIFO and a
receiver overrun error may result.
TX
start
bit 0 to bit 7
stop
start
bit 0 to bit 7
stop
CTS
002aab041
(1) When CTS is LOW, the transmitter keeps sending serial data out.
(2) When CTS goes HIGH before the middle of the last stop bit of the current character, the transmitter finishes sending the current
character, but it does not send the next character.
(3) When CTS goes from HIGH to LOW, the transmitter begins sending data again.
Fig 6.
CTS functional timing
SC16IS741_1
Product data sheet
© NXP B.V. 2010. All rights reserved.
Rev. 01 — 29 April 2010
7 of 52
SC16IS741
NXP Semiconductors
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
7.3 Software flow control
Software flow control is enabled through the enhanced feature register and the Modem
Control Register. Different combinations of software flow control can be enabled by setting
different combinations of EFR[3:0]. Table 3 shows software flow control options.
Table 3.
Software flow control options (EFR[3:0])
EFR[3]
EFR[2]
EFR[1]
EFR[0]
TX, RX software flow control
0
0
X
X
no transmit flow control
1
0
X
X
transmit Xon1, Xoff1
0
1
X
X
transmit Xon2, Xoff2
1
1
X
X
transmit Xon1 and Xon2, Xoff1 and Xoff2
X
X
0
0
no receive flow control
X
X
1
0
receiver compares Xon1, Xoff1
X
X
0
1
receiver compares Xon2, Xoff2
1
0
1
1
transmit Xon1, Xoff1
receiver compares Xon1 or Xon2, Xoff1 or Xoff2
0
1
1
1
transmit Xon2, Xoff2
receiver compares Xon1 or Xon2, Xoff1 or Xoff2
1
1
1
1
transmit Xon1 and Xon2, Xoff1 and Xoff2
receiver compares Xon1 and Xon2, Xoff1 and Xoff2
0
0
1
1
no transmit flow control
receiver compares Xon1 and Xon2, Xoff1 and Xoff2
There are two other enhanced features relating to software flow control:
• Xon Any function (MCR[5]): Receiving any character will resume operation after
recognizing the Xoff character. It is possible that an Xon1 character is recognized as
an Xon Any character, which could cause an Xon2 character to be written to the RX
FIFO.
• Special character (EFR[5]): Incoming data is compared to Xoff2. Detection of the
special character sets the Xoff interrupt (IIR[4]) but does not halt transmission. The
Xoff interrupt is cleared by a read of the IIR. The special character is transferred to the
RX FIFO.
7.3.1 RX
When software flow control operation is enabled, the SC16IS741 will compare incoming
data with Xoff1/Xoff2 programmed characters (in certain cases, Xoff1 and Xoff2 must be
received sequentially). When the correct Xoff characters are received, transmission is
halted after completing transmission of the current character. Xoff detection also sets
IIR[4] (if enabled via IER[5]) and causes IRQ to go LOW.
To resume transmission, an Xon1/Xon2 character must be received (in certain cases
Xon1 and Xon2 must be received sequentially). When the correct Xon characters are
received, IIR[4] is cleared, and the Xoff interrupt disappears.
SC16IS741_1
Product data sheet
© NXP B.V. 2010. All rights reserved.
Rev. 01 — 29 April 2010
8 of 52
SC16IS741
NXP Semiconductors
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
7.3.2 TX
Xoff1/Xoff2 character is transmitted when the RX FIFO has passed the HALT trigger level
programmed in TCR[3:0] or the selectable trigger level in FCR[7:6]
Xon1/Xoff2 character is transmitted when the RX FIFO reaches the RESUME trigger level
programmed in TCR[7:4] or RX FIFO falls below the lower selectable trigger level in
FCR[7:6].
The transmission of Xoff/Xon(s) follows the exact same protocol as transmission of an
ordinary character from the FIFO. This means that even if the word length is set to be 5, 6,
or 7 bits, then the 5, 6, or 7 least significant bits of XOFF1/XOFF2 or XON1/XON2 will be
transmitted. (Note that the transmission of 5, 6, or 7 bits of a character is seldom done, but
this functionality is included to maintain compatibility with earlier designs.)
It is assumed that software flow control and hardware flow control will never be enabled
simultaneously. Figure 7 shows an example of software flow control.
UART1
UART2
TRANSMIT FIFO
RECEIVE FIFO
data
PARALLEL-TO-SERIAL
SERIAL-TO-PARALLEL
Xoff–Xon–Xoff
SERIAL-TO-PARALLEL
PARALLEL-TO-SERIAL
Xon1 WORD
Xon1 WORD
Xon2 WORD
Xon2 WORD
Xoff1 WORD
Xoff1 WORD
Xoff2 WORD
Fig 7.
compare
programmed
Xon-Xoff
characters
002aaa229
Example of software flow control
SC16IS741_1
Product data sheet
Xoff2 WORD
© NXP B.V. 2010. All rights reserved.
Rev. 01 — 29 April 2010
9 of 52
SC16IS741
NXP Semiconductors
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
7.4 Hardware reset, Power-On Reset (POR) and software reset
These three reset methods are identical and will reset the internal registers as indicated in
Table 4.
Table 4 summarizes the state of register.
Table 4.
Register reset[1]
Register
Reset state
Interrupt Enable Register
all bits cleared
Interrupt Identification Register
bit 0 is set; all other bits cleared
FIFO Control Register
all bits cleared
Line Control Register
reset to 0001 1101 (0x1D)
Modem Control Register
all bits cleared
Line Status Register
bit 5 and bit 6 set; all other bits cleared
Modem Status Register
bits 0:3 cleared; bits 4:7 input signals
Enhanced Feature Register
all bits cleared
Receiver Holding Register
pointer logic cleared
Transmitter Holding Register
pointer logic cleared
Transmission Control Register
all bits cleared.
Trigger Level Register
all bits cleared.
Transmit FIFO level
reset to 0100 0000 (0x40)
Receive FIFO level
all bits cleared
Extra Feature Register
all bits cleared
[1]
Registers DLL, DLH, SPR, XON1, XON2, XOFF1, XOFF2 are not reset by the top-level reset signal
RESET, POR or Software Reset, that is, they hold their initialization values during reset.
Table 5 summarizes the state of registers after reset.
Table 5.
Output signals after reset
Signal
Reset state
TX
HIGH
RTS
HIGH
IRQ
HIGH by external pull-up
SC16IS741_1
Product data sheet
© NXP B.V. 2010. All rights reserved.
Rev. 01 — 29 April 2010
10 of 52
SC16IS741
NXP Semiconductors
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
7.5 Interrupts
The SC16IS741 has interrupt generation and prioritization capability. The Interrupt Enable
Register (IER) enables each of the interrupts and the IRQ signal in response to an
interrupt generation. When an interrupt is generated, the IIR indicates that an interrupt is
pending and provides the type of interrupt through IIR[5:0]. Table 6 summarizes the
interrupt control functions.
Table 6.
Summary of interrupt control functions
IIR[5:0]
Priority
level
Interrupt type
Interrupt source
00 0001
none
none
none
00 0110
1
receiver line status
OE, FE, PE, or BI errors occur in characters in the
RX FIFO
00 1100
2
RX time-out
Stale data in RX FIFO
00 0100
2
RHR interrupt
Receive data ready (FIFO disable) or
RX FIFO above trigger level (FIFO enable)
00 0010
3
THR interrupt
Transmit FIFO empty (FIFO disable) or
TX FIFO passes above trigger level (FIFO enable)
00 0000
4
Modem status
Change of state of modem input pins
01 0000
6
Xoff interrupt
Receive Xoff character(s)/ special character
10 0000
7
CTS, RTS
RTS pin or CTS pin change state from active (LOW)
to inactive (HIGH)
It is important to note that for the framing error, parity error, and break conditions, LSR[7]
generates the interrupt. LSR[7] is set when there is an error anywhere in the RX FIFO,
and is cleared only when there are no more errors remaining in the FIFO. LSR[4:2] always
represent the error status for the received character at the top of the RX FIFO. Reading
the RX FIFO updates LSR[4:2] to the appropriate status for the new character at the top of
the FIFO. If the RX FIFO is empty, then LSR[4:2] are all zeros.
For the Xoff interrupt, if an Xoff flow character detection caused the interrupt, the interrupt
is cleared by an Xon flow character detection. If a special character detection caused the
interrupt, the interrupt is cleared by a read of the IIR.
SC16IS741_1
Product data sheet
© NXP B.V. 2010. All rights reserved.
Rev. 01 — 29 April 2010
11 of 52
SC16IS741
NXP Semiconductors
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
7.5.1 Interrupt mode operation
In Interrupt mode (if any bit of IER[3:0] is 1) the host is informed of the status of the
receiver and transmitter by an interrupt signal, IRQ. Therefore, it is not necessary to
continuously poll the Line Status Register (LSR) to see if any interrupt needs to be
serviced. Figure 8 shows Interrupt mode operation.
IIR
read IIR
IRQ
HOST
IER
1
1
THR
1
1
RHR
002aab042
Fig 8.
Interrupt mode operation
7.5.2 Polled mode operation
In Polled mode (IER[3:0] = 0000) the status of the receiver and transmitter can be
checked by polling the Line Status Register (LSR). This mode is an alternative to the FIFO
Interrupt mode of operation where the status of the receiver and transmitter is
automatically known by means of interrupts sent to the CPU. Figure 9 shows FIFO Polled
mode operation.
LSR
read LSR
HOST
IER
0
THR
0
0
0
RHR
002aab043
Fig 9.
FIFO Polled mode operation
SC16IS741_1
Product data sheet
© NXP B.V. 2010. All rights reserved.
Rev. 01 — 29 April 2010
12 of 52
SC16IS741
NXP Semiconductors
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
7.6 Sleep mode
Sleep mode is an enhanced feature of the SC16IS741 UART. It is enabled when EFR[4],
the enhanced functions bit, is set and when IER[4] is set. Sleep mode is entered when:
• The serial data input line, RX, is idle (see Section 7.7 “Break and time-out
conditions”).
• The TX FIFO and TX shift register are empty.
• There are no interrupts pending except THR.
Remark: Sleep mode will not be entered if there is data in the RX FIFO.
In Sleep mode, the clock to the UART is stopped. Since most registers are clocked using
these clocks, the power consumption is greatly reduced. The UART will wake up when
any change is detected on the RX line, when there is any change in the state of the
modem input pins, or if data is written to the TX FIFO.
Remark: Writing to the divisor latches, DLL and DLH, to set the baud clock, must not be
done during Sleep mode. Therefore, it is advisable to disable Sleep mode using IER[4]
before writing to DLL or DLH.
7.7 Break and time-out conditions
When the UART receives a number of characters and these data are not enough to set off
the receive interrupt (because they do not reach the receive trigger level), the UART will
generate a time-out interrupt instead, 4 character times after the last character is
received. The time-out counter will be reset at the center of each stop bit received or each
time the receive FIFO is read.
A break condition is detected when the RX pin is pulled LOW for a duration longer than
the time it takes to send a complete character plus Start, Stop and Parity bits. A break
condition can be sent by setting LCR[6]. When this happens the TX pin will be pulled LOW
until LSR[6] is cleared by the software.
7.8 Programmable baud rate generator
The SC16IS741 UART contains a programmable baud rate generator that takes any clock
input and divides it by a divisor in the range between 1 and (216 – 1). An additional
divide-by-4 prescaler is also available and can be selected by MCR[7], as shown in
Figure 10. The output frequency of the baud rate generator is 16 times the baud rate. The
formula for the divisor is given in Equation 1:
crystal input frequency
⎛ XTAL1
-----------------------------------------------------------------------------------⎞
⎝
⎠
prescaler
divisor = ----------------------------------------------------------------------------------------desired baud rate × 16
(1)
where:
prescaler = 1, when MCR[7] is set to ‘0’ after reset (divide-by-1 clock selected)
prescaler = 4, when MCR[7] is set to ‘1’ after reset (divide-by-4 clock selected).
Remark: The default value of prescaler after reset is divide-by-1.
Figure 10 shows the internal prescaler and baud rate generator circuitry.
SC16IS741_1
Product data sheet
© NXP B.V. 2010. All rights reserved.
Rev. 01 — 29 April 2010
13 of 52
SC16IS741
NXP Semiconductors
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
PRESCALER
LOGIC
(DIVIDE-BY-1)
XTAL1
XTAL2
INTERNAL
OSCILLATOR
LOGIC
MCR[7] = 0
input clock
PRESCALER
LOGIC
(DIVIDE-BY-4)
reference
clock
BAUD RATE
GENERATOR
LOGIC
internal
baud rate
clock for
transmitter
and receiver
MCR[7] = 1
002aaa233
Fig 10. Prescaler and baud rate generator block diagram
DLL and DLH must be written to in order to program the baud rate. DLL and DLH are the
least significant and most significant byte of the baud rate divisor. If DLL and DLH are both
zero, the UART is effectively disabled, as no baud clock will be generated.
Remark: The programmable baud rate generator is provided to select both the transmit
and receive clock rates.
Table 7 and Table 8 show the baud rate and divisor correlation for crystal with frequency
1.8432 MHz and 3.072 MHz, respectively.
Figure 11 shows the crystal clock circuit reference.
Table 7.
Baud rates using a 1.8432 MHz crystal
Desired baud rate
Divisor used to generate
16× clock
Percent error difference
between desired and actual
50
2304
0
75
1536
0
110
1047
0.026
134.5
857
0.058
150
768
0
300
384
0
600
192
0
1200
96
0
1800
64
0
2000
58
0.69
2400
48
0
3600
32
0
4800
24
0
7200
16
0
9600
12
0
19200
6
0
38400
3
0
56000
2
2.86
SC16IS741_1
Product data sheet
© NXP B.V. 2010. All rights reserved.
Rev. 01 — 29 April 2010
14 of 52
SC16IS741
NXP Semiconductors
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
Table 8.
Baud rates using a 3.072 MHz crystal
Desired baud rate
Divisor used to generate
16× clock
Percent error difference
between desired and actual
50
2304
0
75
2560
0
110
1745
0.026
134.5
1428
0.034
150
1280
0
300
640
0
600
320
0
1200
160
0
1800
107
0.312
2000
96
0
2400
80
0
3600
53
0.628
4800
40
0
7200
27
1.23
9600
20
0
19200
10
0
38400
5
0
XTAL1
XTAL2
1.8432 MHz
C1
22 pF
C2
33 pF
002aab402
Fig 11. Crystal oscillator circuit reference
SC16IS741_1
Product data sheet
© NXP B.V. 2010. All rights reserved.
Rev. 01 — 29 April 2010
15 of 52
SC16IS741
NXP Semiconductors
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
8. Register descriptions
The programming combinations for register selection are shown in Table 9.
Table 9.
Register map - read/write properties
Register name Read mode
Write mode
RHR/THR
Receive Holding Register (RHR)
Transmit Holding Register (THR)
IER
Interrupt Enable Register (IER)
Interrupt Enable Register
IIR/FCR
Interrupt Identification Register (IIR)
FIFO Control Register (FCR)
LCR
Line Control Register (LCR)
Line Control Register
MCR
Modem Control Register
(MCR)[1]
LSR
Line Status Register (LSR)
n/a
MSR
Modem Status Register (MSR)
n/a
SPR
Scratchpad Register (SPR)
Scratchpad Register
(TCR)[2]
Transmission Control Register[2]
TCR
Transmission Control Register
TLR
Trigger Level Register (TLR)[2]
Trigger Level Register[2]
TXLVL
Transmit FIFO Level Register
n/a
RXLVL
Receive FIFO Level Register
n/a
EFCR
Extra Features Register
Extra Features Register
(DLL)[3]
divisor latch LSB[3]
DLL
divisor latch LSB
DLH
divisor latch MSB (DLH)[3]
divisor latch MSB[3]
EFR
Enhanced Feature Register (EFR)[4]
Enhanced Feature Register[4]
XON1
Xon1
word[4]
Xon1 word[4]
XON2
Xon2 word[4]
Xon2 word[4]
XOFF1
Xoff1 word[4]
Xoff1 word[4]
XOFF2
Xoff2 word[4]
Xoff2 word[4]
[1]
MCR[7] can only be modified when EFR[4] is set.
[2]
Accessible only when ERF[4] = 1 and MCR[2] = 1, that is, EFR[4] and MCR[2] are read/write enables.
[3]
Accessible only when LCR[7] is logic 1.
[4]
Accessible only when LCR is set to 1011 1111b (0xBF).
SC16IS741_1
Product data sheet
Modem Control Register[1]
© NXP B.V. 2010. All rights reserved.
Rev. 01 — 29 April 2010
16 of 52
xxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxx x x x xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxx xx xx xxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxx xxxxxx xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxx x x
xxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxx xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxxx xxx
SC16IS741 internal registers
Register
address
Register
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
R/W
bit 3
bit 2
bit 1
bit 0
R
bit 3
bit 2
bit 1
bit 0
W
modem status receive line
THR empty
interrupt
status interrupt interrupt
RX data
available
interrupt
R/W
W
NXP Semiconductors
SC16IS741_1
Product data sheet
Table 10.
General register set[1]
0x00
RHR
bit 7
bit 6
bit 5
bit 4
0x00
THR
bit 7
bit 6
bit 5
bit 4
CTS
interrupt
enable[2]
RTS interrupt
enable[2]
0x02
FCR
RX trigger
level (MSB)
RX trigger
level (LSB)
TX trigger
TX trigger
level (MSB)[2] level (LSB)[2]
reserved[3]
TX FIFO
reset[4]
RX FIFO
reset[4]
FIFO enable
0x02
IIR[5]
FIFO enable FIFO enable
interrupt
interrupt
priority bit 4[2] priority bit 3[2]
interrupt
priority bit 2
interrupt
priority bit 1
interrupt
priority bit 0
interrupt status R
0x03
LCR
Divisor Latch set break
Enable
set parity
even parity
parity enable
stop bit
word length
bit 1
word length
bit 0
R/W
0x04
MCR
clock
divisor[2]
IrDA mode
enable[2]
Xon Any[2]
loopback
enable
reserved[3]
TCR and TLR
enable[2]
RTS
reserved[3]
R/W
0x05
LSR
FIFO data
error
THR and
TSR empty
THR empty
break interrupt framing error
parity error
overrun error
data in receiver R
0x06
MSR
0
0
0
CTS
0
0
0
ΔCTS
R
0x07
SPR
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
R/W
0x06
TCR[6]
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
R/W
0x07
TLR[6]
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
R/W
0x08
TXLVL
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
R
0x09
RXLVL
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
R
0x0D
reserved[3]
reserved[3]
reserved[3]
reserved[3]
reserved[3]
reserved[3]
reserved[3]
reserved[3]
reserved[3]
0x0E
UART reset reserved[3]
reserved[3]
reserved[3]
reserved[3]
UART
reserved[3]
software reset
reserved[3]
reserved[3]
R/W
0x0F
EFCR
IrDA mode
reserved[3]
auto RS-485
RTS output
inversion
auto RS-485
RTS direction
control
reserved[3]
transmitter
disable
receiver
disable
9-bit mode
enable
R/W
Special register set[7]
0x00
DLL
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
R/W
0x01
DLH
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
R/W
SC16IS741
17 of 52
© NXP B.V. 2010. All rights reserved.
IER
Sleep
mode[2]
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
Rev. 01 — 29 April 2010
0x01
Xoff[2]
xxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxx x x x xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxx xx xx xxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxx xxxxxx xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxx x x
xxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxx xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxxx xxx
SC16IS741 internal registers …continued
Register
address
Register
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
R/W
NXP Semiconductors
SC16IS741_1
Product data sheet
Table 10.
Enhanced register set[8]
0x02
EFR
Auto CTS
Auto RTS
special
character
detect
enable
enhanced
functions
software flow
control bit 3
software flow
control bit 2
software flow
control bit 1
software flow
control bit 0
R/W
0x04
XON1
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
R/W
0x05
XON2
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
R/W
0x06
XOFF1
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
R/W
0x07
XOFF2
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
R/W
These registers are accessible only when LCR[7] = 0.
[2]
These bits in can only be modified if register bit EFR[4] is enabled.
[3]
These bits are reserved and should be set to 0.
[4]
After Receive FIFO or Transmit FIFO reset (through FCR[1:0]), the user must wait at least 2 × Tclk of XTAL1 before reading or writing data to RHR and THR, respectively.
[5]
Burst reads on the serial interface (that is, reading multiple elements on the I2C-bus without a STOP or repeated START condition, or reading multiple elements on the SPI bus
without de-asserting the CS pin), should not be performed on the IIR register.
[6]
These registers are accessible only when MCR[2] = 1 and EFR[4] = 1.
[7]
The special register set is accessible only when LCR[7] = 1 and not 0xBF.
[8]
Enhanced Feature Registers are only accessible when LCR = 0xBF.
SC16IS741
18 of 52
© NXP B.V. 2010. All rights reserved.
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
Rev. 01 — 29 April 2010
[1]
SC16IS741
NXP Semiconductors
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
8.1 Receive Holding Register (RHR)
The receiver section consists of the Receiver Holding Register (RHR) and the Receiver
Shift Register (RSR). The RHR is actually a 64-byte FIFO. The RSR receives serial data
from the RX pin. The data is converted to parallel data and moved to the RHR. The
receiver section is controlled by the Line Control Register. If the FIFO is disabled, location
zero of the FIFO is used to store the characters.
8.2 Transmit Holding Register (THR)
The transmitter section consists of the Transmit Holding Register (THR) and the Transmit
Shift Register (TSR). The THR is actually a 64-byte FIFO. The THR receives data and
shifts it into the TSR, where it is converted to serial data and moved out on the TX pin. If
the FIFO is disabled, the FIFO is still used to store the byte. Characters are lost if overflow
occurs.
8.3 FIFO Control Register (FCR)
This is a write-only register that is used for enabling the FIFOs, clearing the FIFOs, setting
transmitter and receiver trigger levels. Table 11 shows FIFO Control Register bit settings.
Table 11.
FIFO Control Register bits description
Bit
Symbol
Description
7:6
FCR[7] (MSB), RX trigger. Sets the trigger level for the RX FIFO.
FCR[6] (LSB)
00 = 8 characters
01 = 16 characters
10 = 56 characters
11 = 60 characters
5:4
FCR[5] (MSB), TX trigger. Sets the trigger level for the TX FIFO.
FCR[4] (LSB)
00 = 8 spaces
01 = 16 spaces
10 = 32 spaces
11 = 56 spaces
FCR[5:4] can only be modified and enabled when EFR[4] is set. This is
because the transmit trigger level is regarded as an enhanced function.
3
FCR[3]
reserved
2
FCR[2][1]
reset TX FIFO
logic 0 = no FIFO transmit reset (normal default condition)
logic 1 = clears the contents of the transmit FIFO and resets the FIFO
level logic (the Transmit Shift Register is not cleared or altered). This bit
will return to a logic 0 after clearing the FIFO.
1
FCR[1][1]
reset RX FIFO
logic 0 = no FIFO receive reset (normal default condition)
logic 1 = clears the contents of the receive FIFO and resets the FIFO
level logic (the Receive Shift Register is not cleared or altered). This bit
will return to a logic 0 after clearing the FIFO.
0
FCR[0]
FIFO enable
logic 0 = disable the transmit and receive FIFO (normal default condition)
logic 1 = enable the transmit and receive FIFO
SC16IS741_1
Product data sheet
© NXP B.V. 2010. All rights reserved.
Rev. 01 — 29 April 2010
19 of 52
SC16IS741
NXP Semiconductors
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
[1]
FIFO reset requires at least two XTAL1 clocks, therefore, they cannot be reset without the presence of the
XTAL1 clock.
8.4 Line Control Register (LCR)
This register controls the data communication format. The word length, number of stop
bits, and parity type are selected by writing the appropriate bits to the LCR. Table 12
shows the Line Control Register bit settings.
Table 12.
Line Control Register bits description
Bit
Symbol
Description
7
LCR[7]
divisor latch enable
logic 0 = divisor latch disabled (normal default condition)
logic 1 = divisor latch enabled
6
LCR[6]
Break control bit. When enabled, the break control bit causes a break
condition to be transmitted (the TX output is forced to a logic 0 state).
This condition exists until disabled by setting LCR[6] to a logic 0.
logic 0 = no TX break condition (normal default condition).
logic 1 = forces the transmitter output (TX) to a logic 0 to alert the
communication terminal to a line break condition
5
LCR[5]
Set parity. LCR[5] selects the forced parity format (if LCR[3] = 1).
logic 0 = parity is not forced (normal default condition).
LCR[5] = logic 1 and LCR[4] = logic 0: parity bit is forced to a logical 1
for the transmit and receive data.
LCR[5] = logic 1 and LCR[4] = logic 1: parity bit is forced to a logical 0
for the transmit and receive data.
4
LCR[4]
parity type select
logic 0 = odd parity is generated (if LCR[3] = 1)
logic 1 = even parity is generated (if LCR[3] = 1)
3
LCR[3]
parity enable
logic 0 = no parity (normal default condition).
logic 1 = a parity bit is generated during transmission and the receiver
checks for received parity
2
LCR[2]
Number of stop bits. Specifies the number of stop bits.
0 to 1 stop bit (word length = 5, 6, 7, 8)
1 to 1.5 stop bits (word length = 5)
1 = 2 stop bits (word length = 6, 7, 8)
1:0
LCR[1:0]
Word length bits 1, 0. These two bits specify the word length to be
transmitted or received; see Table 15.
SC16IS741_1
Product data sheet
© NXP B.V. 2010. All rights reserved.
Rev. 01 — 29 April 2010
20 of 52
SC16IS741
NXP Semiconductors
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
Table 13.
LCR[5] parity selection
LCR[5]
LCR[4]
LCR[3]
Parity selection
X
X
0
no parity
0
0
1
odd parity
0
1
1
even parity
1
0
1
forced parity ‘1’
1
1
1
forced parity ‘0’
Table 14.
LCR[2] stop bit length
LCR[2]
Word length (bits)
Stop bit length (bit times)
0
5, 6, 7, 8
1
1
5
11⁄2
1
6, 7, 8
2
Table 15.
LCR[1:0] word length
LCR[1]
LCR[0]
Word length (bits)
0
0
5
0
1
6
1
0
7
1
1
8
SC16IS741_1
Product data sheet
© NXP B.V. 2010. All rights reserved.
Rev. 01 — 29 April 2010
21 of 52
SC16IS741
NXP Semiconductors
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
8.5 Line Status Register (LSR)
Table 16 shows the Line Status Register bit settings.
Table 16.
Line Status Register bits description
Bit
Symbol
Description
7
LSR[7]
FIFO data error.
logic 0 = no error (normal default condition)
logic 1 = at least one parity error, framing error, or break indication is in the
receiver FIFO. This bit is cleared when no more errors are present in the
FIFO.
6
LSR[6]
THR and TSR empty. This bit is the Transmit Empty indicator.
logic 0 = transmitter hold and shift registers are not empty
logic 1 = transmitter hold and shift registers are empty
5
LSR[5]
THR empty. This bit is the Transmit Holding Register Empty indicator.
logic 0 = transmit hold register is not empty
logic 1 = transmit hold register is empty. The host can now load up to
64 characters of data into the THR if the TX FIFO is enabled.
4
LSR[4]
break interrupt
logic 0 = no break condition (normal default condition)
logic 1 = a break condition occurred and associated character is 0x00, that
is, RX was LOW for one character time frame
3
LSR[3]
framing error
logic 0 = no framing error in data being read from RX FIFO (normal default
condition).
logic 1 = framing error occurred in data being read from RX FIFO, that is,
received data did not have a valid stop bit
2
LSR[2]
parity error.
logic 0 = no parity error (normal default condition)
logic 1 = parity error in data being read from RX FIFO
1
LSR[1]
overrun error
logic 0 = no overrun error (normal default condition)
logic 1 = overrun error has occurred
0
LSR[0]
data in receiver
logic 0 = no data in receive FIFO (normal default condition)
logic 1 = at least one character in the RX FIFO
When the LSR is read, LSR[4:2] reflect the error bits (BI, FE, PE) of the character at the
top of the RX FIFO (next character to be read). Therefore, errors in a character are
identified by reading the LSR and then reading the RHR.
LSR[7] is set when there is an error anywhere in the RX FIFO, and is cleared only when
there are no more errors remaining in the FIFO.
SC16IS741_1
Product data sheet
© NXP B.V. 2010. All rights reserved.
Rev. 01 — 29 April 2010
22 of 52
SC16IS741
NXP Semiconductors
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
8.6 Modem Control Register (MCR)
The MCR controls the interface with the mode, data set, or peripheral device that is
emulating the modem. Table 17 shows the Modem Control Register bit settings.
Table 17.
Modem Control Register bits description
Bit
Symbol
Description
7
MCR[7][1]
clock divisor
logic 0 = divide-by-1 clock input
logic 1 = divide-by-4 clock input
6
MCR[6][1]
IrDA mode enable
logic 0 = normal UART mode
logic 1 = IrDA mode
5
MCR[5][1]
Xon Any
logic 0 = disable Xon Any function
logic 1 = enable Xon Any function
4
MCR[4]
enable loopback
logic 0 = normal operating mode
logic 1 = enable local Loopback mode (internal). In this mode the MCR[1:0]
signals are looped back into MSR[4:5] and the TX output is looped back to
the RX input internally.
3
MCR[3]
reserved
2
MCR[2]
TCR and TLR enable
logic 0 = disable the TCR and TLR register.
logic 1 = enable the TCR and TLR register.
1
MCR[1]
RTS
logic 0 = force RTS output to inactive (HIGH)
logic 1 = force RTS output to active (LOW). In Loopback mode, controls
MSR[4]. If Auto RTS is enabled, the RTS output is controlled by hardware
flow control.
0
[1]
MCR[0]
reserved
MCR[7:5] and MCR[2] can only be modified when EFR[4] is set, that is, EFR[4] is a write enable.
SC16IS741_1
Product data sheet
© NXP B.V. 2010. All rights reserved.
Rev. 01 — 29 April 2010
23 of 52
SC16IS741
NXP Semiconductors
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
8.7 Modem Status Register (MSR)
This 8-bit register provides information about the current state of the control lines from the
modem, data set, or peripheral device to the host. It also indicates when a control input
from the modem changes state. Table 18 shows Modem Status Register bit settings.
Table 18.
Modem Status Register bits description
Bit
Symbol
Description
7
MSR[7]
reserved
6
MSR[6]
reserved
5
MSR[5]
reserved
4
MSR[4]
CTS (active HIGH, logical 1). This bit is the complement of the CTS input.
3
MSR[3]
reserved
2
MSR[2]
reserved
1
MSR[1]
reserved
0
MSR[0]
ΔCTS. Indicates that CTS input has changed state. Cleared on a read.
SC16IS741_1
Product data sheet
© NXP B.V. 2010. All rights reserved.
Rev. 01 — 29 April 2010
24 of 52
SC16IS741
NXP Semiconductors
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
8.8 Interrupt Enable Register (IER)
The Interrupt Enable Register (IER) enables each of the six types of interrupt, receiver
error, RHR interrupt, THR interrupt, modem status, Xoff received, or CTS/RTS change of
state from LOW to HIGH. The IRQ output signal is activated in response to interrupt
generation. Table 19 shows the Interrupt Enable Register bit settings.
Table 19.
Interrupt Enable Register bits description
Bit
Symbol
Description
7
IER[7][1]
CTS interrupt enable
logic 0 = disable the CTS interrupt (normal default condition)
logic 1 = enable the CTS interrupt
6
IER[6][1]
RTS interrupt enable
logic 0 = disable the RTS interrupt (normal default condition)
logic 1 = enable the RTS interrupt
5
IER[5][1]
Xoff interrupt
logic 0 = disable the Xoff interrupt (normal default condition)
logic 1 = enable the Xoff interrupt
4
IER[4][1]
Sleep mode
logic 0 = disable Sleep mode (normal default condition)
logic 1 = enable Sleep mode. See Section 7.6 “Sleep mode” for details.
3
IER[3]
reserved
2
IER[2]
Receive Line Status interrupt
logic 0 = disable the receiver line status interrupt (normal default condition)
logic 1 = enable the receiver line status interrupt
1
IER[1]
Transmit Holding Register interrupt.
logic 0 = disable the THR interrupt (normal default condition)
logic 1 = enable the THR interrupt
0
IER[0]
Receive Holding Register interrupt.
logic 0 = disable the RHR interrupt (normal default condition)
logic 1 = enable the RHR interrupt
[1]
IER[7:4] can only be modified if EFR[4] is set, that is, EFR[4] is a write enable. Re-enabling IER[1] will not
cause a new interrupt if the THR is below the threshold.
SC16IS741_1
Product data sheet
© NXP B.V. 2010. All rights reserved.
Rev. 01 — 29 April 2010
25 of 52
SC16IS741
NXP Semiconductors
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
8.9 Interrupt Identification Register (IIR)
The IIR is a read-only 8-bit register which provides the source of the interrupt in a
prioritized manner. Table 20 shows Interrupt Identification Register bit settings.
Table 20.
Interrupt Identification Register bits description
Bit
Symbol
Description
7:6
IIR[7:6]
mirror the contents of FCR[0]
5:1
IIR[5:1]
5-bit encoded interrupt. See Table 21.
0
IIR[0]
interrupt status
logic 0 = an interrupt is pending
logic 1 = no interrupt is pending
Table 21.
Interrupt source
Priority
level
IIR[5]
IIR[4]
IIR[3]
IIR[2]
IIR[1]
IIR[0]
Source of the interrupt
1
0
0
0
1
1
0
Receiver Line Status error
2
0
0
1
1
0
0
Receiver time-out interrupt
2
0
0
0
1
0
0
RHR interrupt
3
0
0
0
0
1
0
THR interrupt
4
0
0
0
0
0
0
modem interrupt
6
0
1
0
0
0
0
received Xoff signal/
special character
7
1
0
0
0
0
0
CTS, RTS change of state from
active (LOW) to inactive
(HIGH)
SC16IS741_1
Product data sheet
© NXP B.V. 2010. All rights reserved.
Rev. 01 — 29 April 2010
26 of 52
SC16IS741
NXP Semiconductors
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
8.10 Enhanced Features Register (EFR)
This 8-bit register enables or disables the enhanced features of the UART. Table 22
shows the enhanced feature register bit settings.
Table 22.
Enhanced Features Register bits description
Bit
Symbol
Description
7
EFR[7]
CTS flow control enable
logic 0 = CTS flow control is disabled (normal default condition)
logic 1 = CTS flow control is enabled. Transmission will stop when a HIGH
signal is detected on the CTS pin.
6
EFR[6]
RTS flow control enable.
logic 0 = RTS flow control is disabled (normal default condition)
logic 1 = RTS flow control is enabled. The RTS pin goes HIGH when the
receiver FIFO halt trigger level TCR[3:0] is reached, and goes LOW when the
receiver FIFO resume transmission trigger level TCR[7:4] is reached.
5
EFR[5]
Special character detect
logic 0 = Special character detect disabled (normal default condition)
logic 1 = Special character detect enabled. Received data is compared with
Xoff2 data. If a match occurs, the received data is transferred to FIFO and
IIR[4] is set to a logical 1 to indicate a special character has been detected.
4
EFR[4]
Enhanced functions enable bit
logic 0 = disables enhanced functions and writing to IER[7:4], FCR[5:4],
MCR[7:5].
logic 1 = enables the enhanced function IER[7:4], FCR[5:4], and MCR[7:5] so
that they can be modified.
3:0
EFR[3:0]
Combinations of software flow control can be selected by programming these
bits. See Table 3 “Software flow control options (EFR[3:0])”.
8.11 Division registers (DLL, DLH)
These are two 8-bit registers which store the 16-bit divisor for generation of the baud clock
in the baud rate generator. DLH stores the most significant part of the divisor. DLL stores
the least significant part of the divisor.
Remark: DLL and DLH can only be written to before Sleep mode is enabled, that is,
before IER[4] is set.
SC16IS741_1
Product data sheet
© NXP B.V. 2010. All rights reserved.
Rev. 01 — 29 April 2010
27 of 52
SC16IS741
NXP Semiconductors
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
8.12 Transmission Control Register (TCR)
This 8-bit register is used to store the RX FIFO threshold levels to stop/start transmission
during hardware/software flow control. Table 23 shows Transmission Control Register bit
settings.
Table 23.
Transmission Control Register bits description
Bit
Symbol
Description
7:4
TCR[7:4]
RX FIFO trigger level to resume
3:0
TCR[3:0]
RX FIFO trigger level to halt transmission
TCR trigger levels are available from 0 to 60 characters with a granularity of four.
Remark: TCR can only be written to when EFR[4] = 1 and MCR[2] = 1. The programmer
must program the TCR such that TCR[3:0] > TCR[7:4]. There is no built-in hardware
check to make sure this condition is met. Also, the TCR must be programmed with this
condition before auto RTS or software flow control is enabled to avoid spurious operation
of the device.
8.13 Trigger Level Register (TLR)
This 8-bit register is used to store the transmit and received FIFO trigger levels used for
interrupt generation. Trigger levels from 4 to 60 can be programmed with a granularity
of 4. Table 24 shows trigger level register bit settings.
Table 24.
Trigger Level Register bits description
Bit
Symbol
Description
7:4
TLR[7:4]
RX FIFO trigger levels (4 to 60), number of characters available.
3:0
TLR[3:0]
TX FIFO trigger levels (4 to 60), number of spaces available.
Remark: TLR can only be written to when EFR[4] = 1 and MCR[2] = 1. If TLR[3:0] or
TLR[7:4] are logical 0, the selectable trigger levels via the FIFO Control Register (FCR)
are used for the transmit and receive FIFO trigger levels. Trigger levels from 4 characters
to 60 characters are available with a granularity of four. The TLR should be programmed
for N⁄4, where N is the desired trigger level.
When the trigger level setting in TLR is zero, the SC16IS741 uses the trigger level setting
defined in FCR. If TLR has non-zero trigger level value, the trigger level defined in FCR is
discarded. This applies to both transmit FIFO and receive FIFO trigger level setting.
When TLR is used for RX trigger level control, FCR[7:6] should be left at the default state,
that is, ‘00’.
8.14 Transmitter FIFO Level register (TXLVL)
This register is a read-only register, it reports the number of spaces available in the
transmit FIFO.
Table 25.
Transmitter FIFO Level register bits description
Bit
Symbol
Description
7
-
not used; set to zeros
6:0
TXLVL[6:0]
number of spaces available in TX FIFO, from 0 (0x00) to 64 (0x40)
SC16IS741_1
Product data sheet
© NXP B.V. 2010. All rights reserved.
Rev. 01 — 29 April 2010
28 of 52
SC16IS741
NXP Semiconductors
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
8.15 Receiver FIFO Level register (RXLVL)
This register is a read-only register, it reports the fill level of the receive FIFO. That is, the
number of characters in the RX FIFO.
Table 26.
Receiver FIFO Level register bits description
Bit
Symbol
Description
7
-
not used; set to zeros
6:0
RXLVL[6:0]
number of characters stored in RX FIFO, from 0 (0x00) to 64 (0x40)
8.16 Extra Features Control Register (EFCR)
Table 27.
Extra Features Control Register bits description
Bit
Symbol
Description
7
IRDA MODE
IrDA mode
0 = IrDA SIR, 3⁄16 pulse ratio, data rate up to 115.2 kbit/s
6
-
reserved
5
RTSINVER
invert RTS signal in RS-485 mode
0: RTS = 0 during transmission and RTS = 1 during reception
1: RTS = 1 during transmission and RTS = 0 during reception
4
RTSCON
enable the transmitter to control the RTS pin
0 = transmitter does not control RTS pin
1 = transmitter controls RTS pin
3
-
reserved
2
TXDISABLE
Disable transmitter. UART does not send serial data out on the
transmit pin, but the transmit FIFO will continue to receive data from
host until full. Any data in the TSR will be sent out before the
transmitter goes into disable state.
0: transmitter is enabled
1: transmitter is disabled
1
RXDISABLE
Disable receiver. UART will stop receiving data immediately once this
bit set to a 1, and any data in the TSR will be sent to the receive FIFO.
User is advised not to set this bit during receiving.
0: receiver is enabled
1: receiver is disabled
0
9-BIT MODE
Enable 9-bit or Multidrop mode (RS-485).
0: normal RS-232 mode
1: enables RS-485 mode
SC16IS741_1
Product data sheet
© NXP B.V. 2010. All rights reserved.
Rev. 01 — 29 April 2010
29 of 52
SC16IS741
NXP Semiconductors
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
9. RS-485 features
9.1 Auto RS-485 RTS control
Normally the RTS pin is controlled by MCR bit 1, or if hardware flow control is enabled, the
logic state of the RTS pin is controlled by the hardware flow control circuitry. EFCR
register bit 4 will take the precedence over the other two modes; once this bit is set, the
transmitter will control the state of the RTS pin. The transmitter automatically asserts the
RTS pin (logic 0) once the host writes data to the transmit FIFO, and deasserts RTS pin
(logic 1) once the last bit of the data has been transmitted.
To use the auto RS-485 RTS mode the software would have to disable the hardware flow
control function.
9.2 RS-485 RTS output inversion
EFCR bit 5 reverses the polarity of the RTS pin if the UART is in auto RS-485 RTS mode.
When the transmitter has data to be sent it will deasserts the RTS pin (logic 1), and when
the last bit of the data has been sent out the transmitter asserts the RTS pin (logic 0).
9.3 Auto RS-485
EFCR bit 0 is used to enable the RS-485 mode (multidrop or 9-bit mode). In this mode of
operation, a ‘master’ station transmits an address character followed by data characters
for the addressed ‘slave’ stations. The slave stations examine the received data and
interrupt the controller if the received character is an address character (parity bit = 1).
To use the auto RS-485 mode the software would have to disable the hardware and
software flow control functions.
9.3.1 Normal multidrop mode
The 9-bit Mode in EFCR (bit 0) is enabled, but not Special Character Detect (EFR bit 5).
The receiver is set to Force Parity 0 (LCR[5:3] = 111) in order to detect address bytes.
With the receiver initially disabled, it ignores all the data bytes (parity bit = 0) until an
address byte is received (parity bit = 1). This address byte will cause the UART to set the
parity error. The UART will generate a line status interrupt (IER bit 2 must be set to ‘1’ at
this time), and at the same time puts this address byte in the RX FIFO. After the controller
examines the byte it must make a decision whether or not to enable the receiver; it should
enable the receiver if the address byte addresses its ID address, and must not enable the
receiver if the address byte does not address its ID address.
If the controller enables the receiver, the receiver will receive the subsequent data until
being disabled by the controller after the controller has received a complete message
from the ‘master’ station. If the controller does not disable the receiver after receiving a
message from the ‘master’ station, the receiver will generate a parity error upon receiving
another address byte. The controller then determines if the address byte addresses its ID
address, if it is not, the controller then can disable the receiver. If the address byte
addresses the ‘slave’ ID address, the controller take no further action, the receiver will
receive the subsequent data.
SC16IS741_1
Product data sheet
© NXP B.V. 2010. All rights reserved.
Rev. 01 — 29 April 2010
30 of 52
SC16IS741
NXP Semiconductors
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
9.3.2 Auto address detection
If Special Character Detect is enabled (EFR[5] is set and the XOFF2 register contains the
address byte) the receiver will try to detect an address byte that matches the programmed
character in the XOFF2 register. If the received byte is a data byte or an address byte that
does not match the programmed character in the XOFF2 register, the receiver will discard
these data. Upon receiving an address byte that matches the Xoff2 character, the receiver
will be automatically enabled if not already enabled, and the address character is pushed
into the RX FIFO along with the parity bit (in place of the parity error bit). The receiver also
generates a line status interrupt (IER[2] must be set to ‘1’ at this time). The receiver will
then receive the subsequent data from the ‘master’ station until being disabled by the
controller after having received a message from the ‘master’ station.
If another address byte is received and this address byte does not match Xoff2 character,
the receiver will be automatically disabled and the address byte is ignored. If the address
byte matches Xoff2 character, the receiver will put this byte in the RX FIFO along with the
parity bit in the parity error bit (LSR bit 2).
10. I2C-bus operation
The two lines of the I2C-bus are a serial data line (SDA) and a serial clock line (SCL). Both
lines are connected to a positive supply via a pull-up resistor, and remain HIGH when the
bus is not busy. Each device is recognized by a unique address whether it is a
microcomputer, LCD driver, memory or keyboard interface and can operate as either a
transmitter or receiver, depending on the function of the device. A device generating a
message or data is a transmitter, and a device receiving the message or data is a
receiver. Obviously, a passive function like an LCD driver could only be a receiver, while a
microcontroller or a memory can both transmit and receive data.
10.1 Data transfers
One data bit is transferred during each clock pulse (see Figure 12). The data on the SDA
line must remain stable during the HIGH period of the clock pulse in order to be valid.
Changes in the data line at this time will be interpreted as control signals. A HIGH-to-LOW
transition of the data line (SDA) while the clock signal (SCL) is HIGH indicates a START
condition, and a LOW-to-HIGH transition of the SDA while SCL is HIGH defines a STOP
condition (see Figure 13). The bus is considered to be busy after the START condition
and free again at a certain time interval after the STOP condition. The START and STOP
conditions are always generated by the master.
SDA
SCL
data line
stable;
data valid
change
of data
allowed
mba607
Fig 12. Bit transfer on the I2C-bus
SC16IS741_1
Product data sheet
© NXP B.V. 2010. All rights reserved.
Rev. 01 — 29 April 2010
31 of 52
SC16IS741
NXP Semiconductors
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
SDA
SCL
S
P
START condition
STOP condition
mba608
Fig 13. START and STOP conditions
The number of data bytes transferred between the START and STOP condition from
transmitter to receiver is not limited. Each byte, which must be eight bits long, is
transferred serially with the most significant bit first, and is followed by an acknowledge bit
(see Figure 14). The clock pulse related to the acknowledge bit is generated by the
master. The device that acknowledges has to pull down the SDA line during the
acknowledge clock pulse, while the transmitting device releases this pulse (see
Figure 15).
acknowledgement signal
from receiver
SDA
MSB
SCL
0
S
1
6
7
8
0
1
2 to 7
ACK
START
condition
8
P
ACK
byte complete,
interrupt within receiver
STOP
condition
clock line held LOW
while interrupt is serviced
002aab012
Fig 14. Data transfer on the I2C-bus
data output
by transmitter
transmitter stays off of the bus
during the acknowledge clock
data output
by receiver
SCL from master
acknowledgement signal
from receiver
S
0
1
6
7
8
002aab013
START
condition
Fig 15. Acknowledge on the I2C-bus
A slave receiver must generate an acknowledge after the reception of each byte, and a
master must generate one after the reception of each byte clocked out of the slave
transmitter.
SC16IS741_1
Product data sheet
© NXP B.V. 2010. All rights reserved.
Rev. 01 — 29 April 2010
32 of 52
SC16IS741
NXP Semiconductors
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
There are two exceptions to the ‘acknowledge after every byte’ rule. The first occurs when
a master is a receiver: it must signal an end of data to the transmitter by not signalling an
acknowledge on the last byte that has been clocked out of the slave. The acknowledge
related clock, generated by the master should still take place, but the SDA line will not be
pulled down. In order to indicate that this is an active and intentional lack of
acknowledgement, we shall term this special condition as a ‘negative acknowledge’.
The second exception is that a slave will send a negative acknowledge when it can no
longer accept additional data bytes. This occurs after an attempted transfer that cannot be
accepted.
10.2 Addressing and transfer formats
Each device on the bus has its own unique address. Before any data is transmitted on the
bus, the master transmits on the bus the address of the slave to be accessed for this
transaction. A well-behaved slave with a matching address, if it exists on the network,
should of course acknowledge the master's addressing. The addressing is done by the
first byte transmitted by the master after the START condition.
An address on the network is seven bits long, appearing as the most significant bits of the
address byte. The last bit is a direction (R/W) bit. A ‘0’ indicates that the master is
transmitting (write) and a ‘1’ indicates that the master requests data (read). A complete
data transfer, comprised of an address byte indicating a ‘write’ and two data bytes is
shown in Figure 16.
SDA
SCL
S
START
condition
0 to 6
address
7
8
0 to 6
R/W
ACK
data
7
8
0 to 6
ACK
data
7
8
P
ACK
STOP
condition
002aab046
Fig 16. A complete data transfer
When an address is sent, each device in the system compares the first seven bits after
the START with its own address. If there is a match, the device will consider itself
addressed by the master, and will send an acknowledge. The device could also determine
if in this transaction it is assigned the role of a slave receiver or slave transmitter,
depending on the R/W bit.
Each node of the I2C-bus network has a unique seven-bit address. The address of a
microcontroller is of course fully programmable, while peripheral devices usually have
fixed and programmable address portions.
When the master is communicating with one device only, data transfers follow the format
of Figure 16, where the R/W bit could indicate either direction. After completing the
transfer and issuing a STOP condition, if a master would like to address some other
device on the network, it could start another transaction by issuing a new START.
SC16IS741_1
Product data sheet
© NXP B.V. 2010. All rights reserved.
Rev. 01 — 29 April 2010
33 of 52
SC16IS741
NXP Semiconductors
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
Another way for a master to communicate with several different devices would be by using
a ‘repeated START’. After the last byte of the transaction was transferred, including its
acknowledge (or negative acknowledge), the master issues another START, followed by
address byte and data—without effecting a STOP. The master may communicate with a
number of different devices, combining ‘reads’ and ‘writes’. After the last transfer takes
place, the master issues a STOP and releases the bus. Possible data formats are
demonstrated in Figure 17. Note that the repeated START allows for both change of a
slave and a change of direction, without releasing the bus. We shall see later on that the
change of direction feature can come in handy even when dealing with a single device.
In a single master system, the repeated START mechanism may be more efficient than
terminating each transfer with a STOP and starting again. In a multimaster environment,
the determination of which format is more efficient could be more complicated, as when a
master is using repeated STARTs it occupies the bus for a long time and thus preventing
other devices from initiating transfers.
data transferred
(n bytes + acknowledge)
master write:
S
SLAVE ADDRESS
START condition
W
write
A
DATA
acknowledge
A
DATA
acknowledge
A
P
acknowledge
STOP condition
data transferred
(n bytes + acknowledge)
master read:
S
SLAVE ADDRESS
START condition
R
read
A
DATA
acknowledge
A
DATA
acknowledge
NA
P
not
acknowledge
STOP condition
data transferred
(n bytes + acknowledge)
combined
formats:
S
SLAVE ADDRESS R/W
START condition
read or
write
A
DATA
acknowledge
A
acknowledge
data transferred
(n bytes + acknowledge)
Sr
SLAVE ADDRESS R/W
repeated
START condition
read or
write
A
DATA
acknowledge
direction of transfer
may change at this point
A
P
acknowledge
STOP condition
002aab458
Fig 17. I2C-bus data formats
SC16IS741_1
Product data sheet
© NXP B.V. 2010. All rights reserved.
Rev. 01 — 29 April 2010
34 of 52
SC16IS741
NXP Semiconductors
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
10.3 Addressing
Before any data is transmitted or received, the master must send the address of the
receiver via the SDA line. The first byte after the START condition carries the address of
the slave device and the read/write bit. Table 28 shows how the SC16IS741’s address can
be selected by using A1 and A0 pins. For example, if these 2 pins are connected to VDD,
then the SC16IS741’s address is set to 0x90, and the master communicates with it
through this address.
Table 28.
SC16IS741 address map
A1
A0
SC16IS741 I2C addresses (hex)[1][2]
VDD
VDD
0x90 (1001 000X)
VDD
VSS
0x92 (1001 001X)
VDD
SCL
0x94 (1001 010X)
VDD
SDA
0x96 (1001 011X)
VSS
VDD
0x98 (1001 100X)
VSS
VSS
0x9A (1001 101X)
VSS
SCL
0x9C (1001 110X)
VSS
SDA
0x9E (1001 111X)
SCL
VDD
0xA0 (1010 000X)
SCL
VSS
0xA2 (1010 001X)
SCL
SCL
0xA4 (1010 010X)
SCL
SDA
0xA6 (1010 011X)
SDA
VDD
0xA8 (1010 100X)
SDA
VSS
0xAA (1010 101X)
SDA
SCL
0xAC (1010 110X)
SDA
SDA
0xAE (1010 111X)
[1]
X = logic 0 for write cycle; X = logic 1 for read cycle.
[2]
Consult Figure 23 and Figure 24 if A1 or A0 is connected to SCL or SDA.
10.4 Use of subaddresses
When a master communicates with the SC16IS741 it must send a subaddress in the byte
following the slave address byte. This subaddress is the internal address of the word the
master wants to access for a single byte transfer, or the beginning of a sequence of
locations for a multi-byte transfer. A subaddress is an 8-bit byte. Unlike the device
address, it does not contain a direction (R/W) bit, and like any byte transferred on the bus
it must be followed by an acknowledge.
Table 29 shows the breakdown of the subaddress (register address) byte. Bit 0 is not
used, bits [2:1] are both set to zeroes, bits [6:3] are used to select one of the device’s
internal registers, and bit 7 is not used.
A register write cycle is shown in Figure 18. The START is followed by a slave address
byte with the direction bit set to ‘write’, a subaddress byte, a number of data bytes, and a
STOP signal. The subaddress indicates which register the master wants to access, and
the data bytes which follow will be written one after the other to the subaddress location.
SC16IS741_1
Product data sheet
© NXP B.V. 2010. All rights reserved.
Rev. 01 — 29 April 2010
35 of 52
SC16IS741
NXP Semiconductors
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
Table 29 and Table 30 show the bits’ presentation at the subaddress byte for I2C-bus and
SPI interfaces. Bit 0 is not used, bits 2:1 select the channel, bits 6:3 select one of the
UART internal registers. Bit 7 is not used with the I2C-bus interface, but it is used by the
SPI interface to indicate a read or a write operation.
S
SLAVE ADDRESS
W
A
REGISTER ADDRESS(1)
A
nDATA
A
P
002aab047
White block: host to SC16IS741
Grey block: SC16IS741 to host
(1) See Table 29 for additional information.
Fig 18. Master writes to slave
The register read cycle (see Figure 19) commences in a similar manner, with the master
sending a slave address with the direction bit set to ‘write’ with a following subaddress.
Then, in order to reverse the direction of the transfer, the master issues a repeated
START followed again by the device address, but this time with the direction bit set to
‘read’. The data bytes starting at the internal subaddress will be clocked out of the device,
each followed by a master-generated acknowledge. The last byte of the read cycle will be
followed by a negative acknowledge, signalling the end of transfer. The cycle is
terminated by a STOP signal.
S
SLAVE ADDRESS
W
A
REGISTER ADDRESS(1)
A
S
nDATA
SLAVE ADDRESS
A
LAST DATA
R
A
NA
P
002aab048
White block: host to SC16IS741
Grey block: SC16IS741 to host
(1) See Table 29 for additional information.
Fig 19. Master read from slave
Table 29.
Register address byte (I2C)
Bit
Name
Function
7
-
not used
6:3
A[3:0]
UART’s internal register select
2:1
CH1, CH0
channel select: CH1 = 0, CH0 = 0
Other values are reserved and should not be used.
0
-
not used
SC16IS741_1
Product data sheet
© NXP B.V. 2010. All rights reserved.
Rev. 01 — 29 April 2010
36 of 52
xxxx xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx x xxxxxxxxxxxxxx xxxxxxxxxx xxx xxxxxx xxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxxxxx
xxxxx xxxxxx xx xxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxx xxxxxxx xxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxx xxxxxxxxxxxxxx xxxxxx xx xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxxxxxxx xxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxx xxxxx x x
R/W
A3
A2
A1
A0
CH1 CH0
X
D7
D6
D5
D4
D3
D2
D1
D0
D6
D5
D4
D3
D2
D1
D0
D6
D5
D4
D3
D2
D1
D0
002aab433
R/W = 0; A[3:0] = register address; CH1 = 0, CH0 = 0
a. Register write
SCLK
SI
R/W
A3
A2
A1
A0
CH1 CH0
NXP Semiconductors
SI
11. SPI operation
SC16IS741_1
Product data sheet
SCLK
X
D7
SO
002aab434
R/W = 1; A[3:0] = register address; CH1 = 0, CH0 = 0
SCLK
SI
R/W
A3
A2
A1
A0
CH1 CH0
X
D7
D7
D6
D5
D4
D3
D2
D1
D0
002aab435
last bit(2)
002aab436
R/W = 0; A[3:0] = 0000; CH1 = 0, CH0 = 0
c. FIFO write cycle
SCLK
SI
R/W
A3
A2
A1
A0
CH1 CH0
X
D7
SO
D6
D5
37 of 52
© NXP B.V. 2010. All rights reserved.
R/W = 1; A[3:0] = 0000; CH1 = 0, CH0 = 0
d. FIFO read cycle
(1) Last bit (D0) of the last byte to be written to the transmit FIFO.
(2) Last bit (D0) of the last byte to be read from the receive FIFO.
Fig 20. SPI operation
D4
D3
D2
D1
D0
D7
D6
D5
D4
D3
D2
D1
D0
SC16IS741
last bit(1)
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
Rev. 01 — 29 April 2010
b. Register read
SC16IS741
NXP Semiconductors
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
Table 30.
Register address byte (SPI)
Bit
Name
Function
7
R/W
1: read from UART
0: write to UART
6:3
A[3:0]
UART’s internal register select
2:1
CH1, CH0
channel select: CH1 = 0, CH0 = 0
Other values are reserved and should not be used.
0
-
not used
12. Limiting values
Table 31. Limiting values
In accordance with the Absolute Maximum Rating System (IEC 60134).
Symbol
Parameter
VDD
supply voltage
Conditions
Min
Max
Unit
−0.3
+4.6
V
VI
input voltage
any input
−0.3
+5.5[1]
V
II
input current
any input
−10
+10
mA
IO
output current
any output
−10
+10
mA
Ptot
total power dissipation
-
300
mW
P/out
power dissipation per
output
-
50
mW
Tamb
ambient temperature
VDD = 2.5 V ± 0.2 V
−40
+85
°C
VDD = 3.3 V ± 0.3 V
−40
+95
°C
operating
Tj
junction temperature
-
+125
°C
Tstg
storage temperature
−65
+150
°C
[1]
5.5 V steady state voltage tolerance on inputs and outputs is valid only when the supply voltage is present.
4.6 V steady state voltage tolerance on inputs and outputs when no supply voltage is present.
13. Static characteristics
Table 32. Static characteristics
VDD = 2.5 V ± 0.2 V, Tamb = −40 °C to +85 °C; or VDD = 3.3 V ± 0.3 V, Tamb = −40 °C to +95 °C; unless otherwise specified.
Symbol
Parameter
Conditions
VDD = 2.5 V
Min
VDD = 3.3 V
Unit
Max
Min
Max
2.3
2.7
3.0
3.6
V
-
6.0
-
6.0
mA
1.6
5.5[1]
2.0
5.5[1]
V
Supplies
VDD
supply voltage
IDD
supply current
operating; no load
Inputs I2C/SPI, RX, CTS
VIH
HIGH-level input voltage
VIL
LOW-level input voltage
IL
leakage current
Ci
input capacitance
input; VI = 0 V or 5.5 V[1]
SC16IS741_1
Product data sheet
-
0.6
-
0.8
V
-
1
-
1
μA
-
3
-
3
pF
© NXP B.V. 2010. All rights reserved.
Rev. 01 — 29 April 2010
38 of 52
SC16IS741
NXP Semiconductors
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
Table 32. Static characteristics …continued
VDD = 2.5 V ± 0.2 V, Tamb = −40 °C to +85 °C; or VDD = 3.3 V ± 0.3 V, Tamb = −40 °C to +95 °C; unless otherwise specified.
Symbol
Parameter
Conditions
VDD = 2.5 V
Min
Max
VDD = 3.3 V
Min
Max
Unit
Outputs TX, RTS, SO
VOH
HIGH-level output voltage
LOW-level output voltage
VOL
IOH = −400 μA
1.85
-
-
-
V
IOH = −4 mA
-
-
2.4
-
V
IOL = 1.6 mA
-
0.4
-
-
V
IOL = 4 mA
-
-
-
0.4
V
-
4
-
4
pF
IOL = 1.6 mA
-
0.4
-
-
V
IOL = 4 mA
-
-
-
0.4
V
-
4
-
4
pF
output capacitance
Co
Output IRQ
VOL
LOW-level output voltage
output capacitance
Co
I2C-bus input/output SDA
VIH
HIGH-level input voltage
1.6
5.5[1]
2.0
5.5[1]
V
VIL
LOW-level input voltage
-
0.6
-
0.8
V
VOL
LOW-level output voltage
IL
leakage current
Co
output capacitance
I2C-bus
IOL = 1.6 mA
-
0.4
-
-
V
IOL = 4 mA
-
-
-
0.4
V
input; VI = 0 V or 5.5 V[1]
-
10
-
10
μA
-
7
-
7
pF
1.6
5.5[1]
2.0
5.5[1]
V
-
0.6
-
0.8
V
-
10
-
10
μA
-
7
-
7
pF
1.8
5.5[1]
2.4
5.5[1]
V
-
0.45
-
0.6
V
−30
+30
−30
+30
μA
-
3
-
3
pF
-
30
-
30
μA
inputs SCL, CS/A0, SI/A1
VIH
HIGH-level input voltage
VIL
LOW-level input voltage
IL
leakage current
Ci
input capacitance
input; VI = 0 V or 5.5
V[1]
Clock input XTAL1[2]
VIH
HIGH-level input voltage
VIL
LOW-level input voltage
IL
leakage current
Ci
input capacitance
input; VI = 0 V or 5.5
V[1]
Sleep current
IDD(sleep)
sleep mode supply current
inputs are at VDD or ground
[1]
5.5 V steady state voltage tolerance on inputs and outputs is valid only when the supply voltage is present. 3.8 V steady state voltage
tolerance on inputs and outputs when no supply voltage is present.
[2]
XTAL2 should be left open when XTAL1 is driven by an external clock.
SC16IS741_1
Product data sheet
© NXP B.V. 2010. All rights reserved.
Rev. 01 — 29 April 2010
39 of 52
SC16IS741
NXP Semiconductors
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
14. Dynamic characteristics
Table 33. I2C-bus timing specifications[1]
All the timing limits are valid within the operating supply voltage, ambient temperature range and output load;
VDD = 2.5 V ± 0.2 V, Tamb = −40 °C to +85 °C; or VDD = 3.3 V ± 0.3 V, Tamb = −40 °C to +95 °C; and refer to VIL and VIH with
an input voltage of VSS to VDD. All output load = 25 pF, except SDA output load = 400 pF.
Symbol
Parameter
Conditions
Standard mode
I2C-bus
[2]
Fast mode
I2C-bus
Min
Max
Min
Max
0
100
0
400
Unit
fSCL
SCL clock frequency
tBUF
bus free time between a STOP and START
condition
4.7
-
1.3
-
μs
tHD;STA
hold time (repeated) START condition
4.0
-
0.6
-
μs
tSU;STA
set-up time for a repeated START condition
4.7
-
0.6
-
μs
tSU;STO
set-up time for STOP condition
4.7
-
0.6
-
μs
tHD;DAT
data hold time
0
-
0
-
ns
tVD;ACK
data valid acknowledge time
-
0.6
-
0.6
μs
tVD;DAT
data valid time
-
0.6
-
0.6
ns
tSU;DAT
data set-up time
250
-
150
-
ns
tLOW
LOW period of the SCL clock
4.7
-
1.3
-
μs
tHIGH
HIGH period of the SCL clock
4.0
-
0.6
-
μs
SCL LOW to
data out valid
kHz
tf
fall time of both SDA and SCL signals
-
300
-
300
ns
tr
rise time of both SDA and SCL signals
-
1000
-
300
ns
tSP
pulse width of spikes that must be
suppressed by the input filter
-
50
-
50
ns
td(int_v)modem
modem interrupt valid delay time
0.2
-
0.2
-
μs
td(int_clr)modem modem interrupt clear delay time
0.2
-
0.2
-
μs
td(int_v)rx
receive interrupt valid delay time
0.2
-
0.2
-
μs
td(int_clr)rx
receive interrupt clear delay time
0.2
-
0.2
-
μs
td(int_clr)tx
transmit interrupt clear delay time
1.0
-
0.5
-
μs
td(rst-SCL)
SCL delay time after reset
3
-
3
-
μs
td(SCL-A)
delay time from SCL to address
-
30
-
30
ns
td(SDA-A)
delay time from SDA to address
-
30
-
30
ns
td(A-SCL)
delay time from address to SCL
-
30
-
30
ns
td(A-SDA)
delay time from address to SDA
-
30
-
30
ns
tw(rst)
reset pulse width
3
-
3
-
μs
[3][4]
[1]
A detailed description of the I2C-bus specification, with applications, is given in user manual UM10204: “I2C-bus specification and user
manual”. This may be found at www.nxp.com/acrobat_download/usermanuals/UM10204.pdf.
[2]
Minimum SCL clock frequency is limited by the bus time-out feature, which resets the serial bus interface if SDA is held LOW for a
minimum of 25 ms.
[3]
2 XTAL1 clocks or 3 μs, whichever is less.
[4]
The device will not acknowledge if an I2C-bus transaction occurs during the ‘SCL delay time after reset’.
SC16IS741_1
Product data sheet
© NXP B.V. 2010. All rights reserved.
Rev. 01 — 29 April 2010
40 of 52
SC16IS741
NXP Semiconductors
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
RESET
tw(rst)
td(rst-SCL)
SCL
002aaf472
Fig 21. SCL delay after reset
protocol
START
condition
(S)
bit 7
MSB
(A7)
tSU;STA
tLOW
bit 0
LSB
(R/W)
bit 6
(A6)
tHIGH
acknowledge
(A)
STOP
condition
(P)
1/f
SCL
SCL
tBUF
tf
tr
tSP
SDA
tSU;DAT
tHD;STA
tHD;DAT
tVD;DAT
tVD;ACK
tSU;STO
002aab489
Rise and fall times refer to VIL and VIH.
Fig 22. I2C-bus timing diagram
SCL, SDA
td(SCL-A)
td(SDA-A)
A1, A0
002aaf164
Fig 23. I2C-bus address selection A1/A0 delay
SCL, SDA
td(A-SCL)
td(A-SDA)
A1, A0
002aaf165
Fig 24. I2C-bus address selection SCL/SDA delay
SC16IS741_1
Product data sheet
© NXP B.V. 2010. All rights reserved.
Rev. 01 — 29 April 2010
41 of 52
SC16IS741
NXP Semiconductors
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
ACK to master
SLAVE ADDRESS
SDA
W
A
AMSR REGISTER
A
S
SLAVE ADDRESS
R
A
A
DATA
IRQ
td(int_v)modem
td(int_clr)modem
MODEM pin
002aaf468
Fig 25. Modem input pin interrupt
start
bit
RX
next
start
bit
stop
bit
D0
D1
D2
D3
D4
D5
D6
D7
td(int_v)rx
IRQ
002aaf470
Fig 26. Receive interrupt
SDA
SLAVE ADDRESS
W
A
A
A
RHR
S
R
SLAVE ADDRESS
A
A
DATA
P
IRQ
td(int_clr)rx
002aaf469
Fig 27. Receive interrupt clear
SDA
SLAVE ADDRESS
W
A
ATHR REGISTER
A
DATA
A
IRQ
td(int_clr)tx
002aaf471
Fig 28. Transmit interrupt clear
SC16IS741_1
Product data sheet
© NXP B.V. 2010. All rights reserved.
Rev. 01 — 29 April 2010
42 of 52
SC16IS741
NXP Semiconductors
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
Table 34. fXTAL dynamic characteristics
VDD = 2.5 V ± 0.2 V, Tamb = −40 °C to +85 °C; or VDD = 3.3 V ± 0.3 V, Tamb = −40 °C to +95 °C
Symbol
Parameter
tWH
pulse width HIGH
tWL
pulse width LOW
[2]
VDD = 2.5 V
[1][2]
frequency on pin XTAL
fXTAL
[1]
Conditions
VDD = 3.3 V
Unit
Min
Max
Min
Max
10
-
6
-
ns
10
-
6
-
ns
-
48
-
80
MHz
Applies to external clock, crystal oscillator max. 24 MHz.
1
f XTAL = --------------t w ( clk )
tWL
tWH
external clock
tw(clk)
002aac357
Fig 29. External clock timing
SC16IS741_1
Product data sheet
© NXP B.V. 2010. All rights reserved.
Rev. 01 — 29 April 2010
43 of 52
SC16IS741
NXP Semiconductors
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
Table 35. SPI-bus timing specifications
All the timing limits are valid within the operating supply voltage, ambient temperature range and output load;
VDD = 2.5 V ± 0.2 V, Tamb = −40 °C to +85 °C; or VDD = 3.3 V ± 0.3 V, Tamb = −40 °C to +95 °C; and refer to VIL and VIH with
an input voltage of VSS to VDD. All output load = 25 pF, unless otherwise specified.
Symbol
Parameter
Conditions
Min
Typ
Max
Unit
tTR
CS HIGH to SO 3-state delay time
CL = 100 pF
-
-
100
ns
tCSS
CS to SCLK setup time
100
-
-
ns
tCSH
CS to SCLK hold time
tDO
SCLK fall to SO valid delay time
tDS
20
-
-
ns
-
-
100
ns
SI to SCLK setup time
100
-
-
ns
tDH
SI to SCLK hold time
20
-
-
ns
tCP
SCLK period
250
-
-
ns
tCH
SCLK HIGH time
100
-
-
ns
tCL
SCLK LOW time
100
-
-
ns
tCSW
CS HIGH pulse width
200
-
-
ns
CL = 100 pF
tCL + tCH
td(int_clr)tx
transmit interrupt clear delay time
200
-
-
ns
td(int_clr)rx
receive interrupt clear delay time
200
-
-
ns
tw(rst)
reset pulse width
3
-
-
μs
CS
tCSH
tCL
tCSS
tCH
tCSH
tCSW
SCLK
tDH
tDS
SI
tDO
tTR
SO
002aab066
Fig 30. Detailed SPI-bus timing
SC16IS741_1
Product data sheet
© NXP B.V. 2010. All rights reserved.
Rev. 01 — 29 April 2010
44 of 52
SC16IS741
NXP Semiconductors
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
CS
SCLK
SI
R/W
A3
A2
A1
A0
CH1 CH0
X
D7
D6
D5
D4
D3
D2
D1
D0
SO
td(int_clr)tx
IRQ
002aaf473
R/W = 0; A[3:0] = THR (0x00); CH1 = 0; CH0 = 0
Fig 31. SPI write THR to clear TX INT
CS
SCLK
SI
R/W
A3
A2
A1
A0
CH1 CH0
X
D7
SO
D6
D5
D4
D3
D2
D1
D0
td(int_clr)rx
IRQ
002aaf474
R/W = 1; A[3:0] = RHR (0x00); CH1 = 0; CH0 = 0
Fig 32. Read RHR to clear RX INT
SC16IS741_1
Product data sheet
© NXP B.V. 2010. All rights reserved.
Rev. 01 — 29 April 2010
45 of 52
SC16IS741
NXP Semiconductors
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
15. Package outline
TSSOP16: plastic thin shrink small outline package; 16 leads; body width 4.4 mm
SOT403-1
E
D
A
X
c
y
HE
v M A
Z
9
16
Q
(A 3)
A2
A
A1
pin 1 index
θ
Lp
L
1
8
e
detail X
w M
bp
0
2.5
5 mm
scale
DIMENSIONS (mm are the original dimensions)
UNIT
A
max.
A1
A2
A3
bp
c
D (1)
E (2)
e
HE
L
Lp
Q
v
w
y
Z (1)
θ
mm
1.1
0.15
0.05
0.95
0.80
0.25
0.30
0.19
0.2
0.1
5.1
4.9
4.5
4.3
0.65
6.6
6.2
1
0.75
0.50
0.4
0.3
0.2
0.13
0.1
0.40
0.06
8
o
0
o
Notes
1. Plastic or metal protrusions of 0.15 mm maximum per side are not included.
2. Plastic interlead protrusions of 0.25 mm maximum per side are not included.
OUTLINE
VERSION
SOT403-1
REFERENCES
IEC
JEDEC
JEITA
EUROPEAN
PROJECTION
ISSUE DATE
99-12-27
03-02-18
MO-153
Fig 33. Package outline SOT403-1 (TSSOP16)
SC16IS741_1
Product data sheet
© NXP B.V. 2010. All rights reserved.
Rev. 01 — 29 April 2010
46 of 52
SC16IS741
NXP Semiconductors
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
16. Handling information
All input and output pins are protected against ElectroStatic Discharge (ESD) under
normal handling. When handling ensure that the appropriate precautions are taken as
described in JESD625-A or equivalent standards.
17. Soldering of SMD packages
This text provides a very brief insight into a complex technology. A more in-depth account
of soldering ICs can be found in Application Note AN10365 “Surface mount reflow
soldering description”.
17.1 Introduction to soldering
Soldering is one of the most common methods through which packages are attached to
Printed Circuit Boards (PCBs), to form electrical circuits. The soldered joint provides both
the mechanical and the electrical connection. There is no single soldering method that is
ideal for all IC packages. Wave soldering is often preferred when through-hole and
Surface Mount Devices (SMDs) are mixed on one printed wiring board; however, it is not
suitable for fine pitch SMDs. Reflow soldering is ideal for the small pitches and high
densities that come with increased miniaturization.
17.2 Wave and reflow soldering
Wave soldering is a joining technology in which the joints are made by solder coming from
a standing wave of liquid solder. The wave soldering process is suitable for the following:
• Through-hole components
• Leaded or leadless SMDs, which are glued to the surface of the printed circuit board
Not all SMDs can be wave soldered. Packages with solder balls, and some leadless
packages which have solder lands underneath the body, cannot be wave soldered. Also,
leaded SMDs with leads having a pitch smaller than ~0.6 mm cannot be wave soldered,
due to an increased probability of bridging.
The reflow soldering process involves applying solder paste to a board, followed by
component placement and exposure to a temperature profile. Leaded packages,
packages with solder balls, and leadless packages are all reflow solderable.
Key characteristics in both wave and reflow soldering are:
•
•
•
•
•
•
Board specifications, including the board finish, solder masks and vias
Package footprints, including solder thieves and orientation
The moisture sensitivity level of the packages
Package placement
Inspection and repair
Lead-free soldering versus SnPb soldering
17.3 Wave soldering
Key characteristics in wave soldering are:
SC16IS741_1
Product data sheet
© NXP B.V. 2010. All rights reserved.
Rev. 01 — 29 April 2010
47 of 52
SC16IS741
NXP Semiconductors
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
• Process issues, such as application of adhesive and flux, clinching of leads, board
transport, the solder wave parameters, and the time during which components are
exposed to the wave
• Solder bath specifications, including temperature and impurities
17.4 Reflow soldering
Key characteristics in reflow soldering are:
• Lead-free versus SnPb soldering; note that a lead-free reflow process usually leads to
higher minimum peak temperatures (see Figure 34) than a SnPb process, thus
reducing the process window
• Solder paste printing issues including smearing, release, and adjusting the process
window for a mix of large and small components on one board
• Reflow temperature profile; this profile includes preheat, reflow (in which the board is
heated to the peak temperature) and cooling down. It is imperative that the peak
temperature is high enough for the solder to make reliable solder joints (a solder paste
characteristic). In addition, the peak temperature must be low enough that the
packages and/or boards are not damaged. The peak temperature of the package
depends on package thickness and volume and is classified in accordance with
Table 36 and 37
Table 36.
SnPb eutectic process (from J-STD-020C)
Package thickness (mm)
Package reflow temperature (°C)
Volume (mm3)
< 350
≥ 350
< 2.5
235
220
≥ 2.5
220
220
Table 37.
Lead-free process (from J-STD-020C)
Package thickness (mm)
Package reflow temperature (°C)
Volume (mm3)
< 350
350 to 2000
> 2000
< 1.6
260
260
260
1.6 to 2.5
260
250
245
> 2.5
250
245
245
Moisture sensitivity precautions, as indicated on the packing, must be respected at all
times.
Studies have shown that small packages reach higher temperatures during reflow
soldering, see Figure 34.
SC16IS741_1
Product data sheet
© NXP B.V. 2010. All rights reserved.
Rev. 01 — 29 April 2010
48 of 52
SC16IS741
NXP Semiconductors
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
maximum peak temperature
= MSL limit, damage level
temperature
minimum peak temperature
= minimum soldering temperature
peak
temperature
time
001aac844
MSL: Moisture Sensitivity Level
Fig 34. Temperature profiles for large and small components
For further information on temperature profiles, refer to Application Note AN10365
“Surface mount reflow soldering description”.
18. Abbreviations
Table 38.
Abbreviations
Acronym
Description
CPU
Central Processing Unit
FIFO
First In, First Out
I2C-bus
Inter IC bus
IrDA
Infrared Data Association
LCD
Liquid Crystal Display
MIR
Medium InfraRed
POR
Power-On Reset
SIR
Serial InfraRed
SPI
Serial Peripheral Interface
UART
Universal Asynchronous Receiver/Transmitter
19. Revision history
Table 39.
Revision history
Document ID
Release date
Data sheet status
Change notice
Supersedes
SC16IS741_1
20100429
Product data sheet
-
-
SC16IS741_1
Product data sheet
© NXP B.V. 2010. All rights reserved.
Rev. 01 — 29 April 2010
49 of 52
SC16IS741
NXP Semiconductors
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
20. Legal information
20.1 Data sheet status
Document status[1][2]
Product status[3]
Definition
Objective [short] data sheet
Development
This document contains data from the objective specification for product development.
Preliminary [short] data sheet
Qualification
This document contains data from the preliminary specification.
Product [short] data sheet
Production
This document contains the product specification.
[1]
Please consult the most recently issued document before initiating or completing a design.
[2]
The term ‘short data sheet’ is explained in section “Definitions”.
[3]
The product status of device(s) described in this document may have changed since this document was published and may differ in case of multiple devices. The latest product status
information is available on the Internet at URL http://www.nxp.com.
20.2 Definitions
Draft — The document is a draft version only. The content is still under
internal review and subject to formal approval, which may result in
modifications or additions. NXP Semiconductors does not give any
representations or warranties as to the accuracy or completeness of
information included herein and shall have no liability for the consequences of
use of such information.
Short data sheet — A short data sheet is an extract from a full data sheet
with the same product type number(s) and title. A short data sheet is intended
for quick reference only and should not be relied upon to contain detailed and
full information. For detailed and full information see the relevant full data
sheet, which is available on request via the local NXP Semiconductors sales
office. In case of any inconsistency or conflict with the short data sheet, the
full data sheet shall prevail.
Product specification — The information and data provided in a Product
data sheet shall define the specification of the product as agreed between
NXP Semiconductors and its customer, unless NXP Semiconductors and
customer have explicitly agreed otherwise in writing. In no event however,
shall an agreement be valid in which the NXP Semiconductors product is
deemed to offer functions and qualities beyond those described in the
Product data sheet.
20.3 Disclaimers
Limited warranty and liability — Information in this document is believed to
be accurate and reliable. However, NXP Semiconductors does not give any
representations or warranties, expressed or implied, as to the accuracy or
completeness of such information and shall have no liability for the
consequences of use of such information.
In no event shall NXP Semiconductors be liable for any indirect, incidental,
punitive, special or consequential damages (including - without limitation - lost
profits, lost savings, business interruption, costs related to the removal or
replacement of any products or rework charges) whether or not such
damages are based on tort (including negligence), warranty, breach of
contract or any other legal theory.
Notwithstanding any damages that customer might incur for any reason
whatsoever, NXP Semiconductors’ aggregate and cumulative liability towards
customer for the products described herein shall be limited in accordance
with the Terms and conditions of commercial sale of NXP Semiconductors.
malfunction of an NXP Semiconductors product can reasonably be expected
to result in personal injury, death or severe property or environmental
damage. NXP Semiconductors accepts no liability for inclusion and/or use of
NXP Semiconductors products in such equipment or applications and
therefore such inclusion and/or use is at the customer’s own risk.
Applications — Applications that are described herein for any of these
products are for illustrative purposes only. NXP Semiconductors makes no
representation or warranty that such applications will be suitable for the
specified use without further testing or modification.
NXP Semiconductors does not accept any liability related to any default,
damage, costs or problem which is based on a weakness or default in the
customer application/use or the application/use of customer’s third party
customer(s) (hereinafter both referred to as “Application”). It is customer’s
sole responsibility to check whether the NXP Semiconductors product is
suitable and fit for the Application planned. Customer has to do all necessary
testing for the Application in order to avoid a default of the Application and the
product. NXP Semiconductors does not accept any liability in this respect.
Limiting values — Stress above one or more limiting values (as defined in
the Absolute Maximum Ratings System of IEC 60134) will cause permanent
damage to the device. Limiting values are stress ratings only and (proper)
operation of the device at these or any other conditions above those given in
the Recommended operating conditions section (if present) or the
Characteristics sections of this document is not warranted. Constant or
repeated exposure to limiting values will permanently and irreversibly affect
the quality and reliability of the device.
Terms and conditions of commercial sale — NXP Semiconductors
products are sold subject to the general terms and conditions of commercial
sale, as published at http://www.nxp.com/profile/terms, unless otherwise
agreed in a valid written individual agreement. In case an individual
agreement is concluded only the terms and conditions of the respective
agreement shall apply. NXP Semiconductors hereby expressly objects to
applying the customer’s general terms and conditions with regard to the
purchase of NXP Semiconductors products by customer.
No offer to sell or license — Nothing in this document may be interpreted or
construed as an offer to sell products that is open for acceptance or the grant,
conveyance or implication of any license under any copyrights, patents or
other industrial or intellectual property rights.
Export control — This document as well as the item(s) described herein
may be subject to export control regulations. Export might require a prior
authorization from national authorities.
Right to make changes — NXP Semiconductors reserves the right to make
changes to information published in this document, including without
limitation specifications and product descriptions, at any time and without
notice. This document supersedes and replaces all information supplied prior
to the publication hereof.
Non-automotive qualified products — Unless this data sheet expressly
states that this specific NXP Semiconductors product is automotive qualified,
the product is not suitable for automotive use. It is neither qualified nor tested
in accordance with automotive testing or application requirements. NXP
Semiconductors accepts no liability for inclusion and/or use of
non-automotive qualified products in automotive equipment or applications.
Suitability for use — NXP Semiconductors products are not designed,
authorized or warranted to be suitable for use in medical, military, aircraft,
space or life support equipment, nor in applications where failure or
In the event that customer uses the product for design-in and use in
automotive applications to automotive specifications and standards, customer
(a) shall use the product without NXP Semiconductors’ warranty of the
SC16IS741_1
Product data sheet
© NXP B.V. 2010. All rights reserved.
Rev. 01 — 29 April 2010
50 of 52
SC16IS741
NXP Semiconductors
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
product for such automotive applications, use and specifications, and (b)
whenever customer uses the product for automotive applications beyond
NXP Semiconductors’ specifications such use shall be solely at customer’s
own risk, and (c) customer fully indemnifies NXP Semiconductors for any
liability, damages or failed product claims resulting from customer design and
use of the product for automotive applications beyond NXP Semiconductors’
standard warranty and NXP Semiconductors’ product specifications.
20.4 Trademarks
Notice: All referenced brands, product names, service names and trademarks
are the property of their respective owners.
I2C-bus — logo is a trademark of NXP B.V.
21. Contact information
For more information, please visit: http://www.nxp.com
For sales office addresses, please send an email to: [email protected]
SC16IS741_1
Product data sheet
© NXP B.V. 2010. All rights reserved.
Rev. 01 — 29 April 2010
51 of 52
SC16IS741
NXP Semiconductors
Single UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR
22. Contents
1
2
2.1
2.2
2.3
3
4
5
6
6.1
6.2
7
7.1
7.2
7.2.1
7.2.2
7.3
7.3.1
7.3.2
7.4
7.5
7.5.1
7.5.2
7.6
7.7
7.8
8
8.1
8.2
8.3
8.4
8.5
8.6
8.7
8.8
8.9
8.10
8.11
8.12
8.13
8.14
8.15
8.16
9
9.1
General description . . . . . . . . . . . . . . . . . . . . . . 1
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
General features . . . . . . . . . . . . . . . . . . . . . . . . 1
I2C-bus features . . . . . . . . . . . . . . . . . . . . . . . . 2
SPI features . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Ordering information . . . . . . . . . . . . . . . . . . . . . 2
Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Pinning information . . . . . . . . . . . . . . . . . . . . . . 4
Pinning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Pin description . . . . . . . . . . . . . . . . . . . . . . . . . 4
Functional description . . . . . . . . . . . . . . . . . . . 5
Trigger levels . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Hardware flow control . . . . . . . . . . . . . . . . . . . . 6
Auto RTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Auto CTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Software flow control . . . . . . . . . . . . . . . . . . . . 8
RX. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
TX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Hardware reset, Power-On Reset (POR)
and software reset . . . . . . . . . . . . . . . . . . . . . 10
Interrupts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Interrupt mode operation . . . . . . . . . . . . . . . . 12
Polled mode operation . . . . . . . . . . . . . . . . . . 12
Sleep mode . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Break and time-out conditions . . . . . . . . . . . . 13
Programmable baud rate generator . . . . . . . . 13
Register descriptions . . . . . . . . . . . . . . . . . . . 16
Receive Holding Register (RHR) . . . . . . . . . . 19
Transmit Holding Register (THR) . . . . . . . . . . 19
FIFO Control Register (FCR) . . . . . . . . . . . . . 19
Line Control Register (LCR) . . . . . . . . . . . . . . 20
Line Status Register (LSR) . . . . . . . . . . . . . . . 22
Modem Control Register (MCR) . . . . . . . . . . . 23
Modem Status Register (MSR) . . . . . . . . . . . . 24
Interrupt Enable Register (IER) . . . . . . . . . . . 25
Interrupt Identification Register (IIR). . . . . . . . 26
Enhanced Features Register (EFR) . . . . . . . . 27
Division registers (DLL, DLH) . . . . . . . . . . . . . 27
Transmission Control Register (TCR). . . . . . . 28
Trigger Level Register (TLR) . . . . . . . . . . . . . 28
Transmitter FIFO Level register (TXLVL) . . . . 28
Receiver FIFO Level register (RXLVL) . . . . . . 29
Extra Features Control Register (EFCR) . . . . 29
RS-485 features . . . . . . . . . . . . . . . . . . . . . . . . 30
Auto RS-485 RTS control . . . . . . . . . . . . . . . . 30
9.2
9.3
9.3.1
9.3.2
10
10.1
10.2
10.3
10.4
11
12
13
14
15
16
17
17.1
17.2
17.3
17.4
18
19
20
20.1
20.2
20.3
20.4
21
22
RS-485 RTS output inversion . . . . . . . . . . . .
Auto RS-485 . . . . . . . . . . . . . . . . . . . . . . . . .
Normal multidrop mode . . . . . . . . . . . . . . . . .
Auto address detection . . . . . . . . . . . . . . . . .
I2C-bus operation . . . . . . . . . . . . . . . . . . . . . .
Data transfers . . . . . . . . . . . . . . . . . . . . . . . .
Addressing and transfer formats . . . . . . . . . .
Addressing . . . . . . . . . . . . . . . . . . . . . . . . . . .
Use of subaddresses . . . . . . . . . . . . . . . . . . .
SPI operation . . . . . . . . . . . . . . . . . . . . . . . . . .
Limiting values . . . . . . . . . . . . . . . . . . . . . . . .
Static characteristics . . . . . . . . . . . . . . . . . . .
Dynamic characteristics. . . . . . . . . . . . . . . . .
Package outline. . . . . . . . . . . . . . . . . . . . . . . .
Handling information . . . . . . . . . . . . . . . . . . .
Soldering of SMD packages . . . . . . . . . . . . . .
Introduction to soldering. . . . . . . . . . . . . . . . .
Wave and reflow soldering. . . . . . . . . . . . . . .
Wave soldering . . . . . . . . . . . . . . . . . . . . . . .
Reflow soldering . . . . . . . . . . . . . . . . . . . . . .
Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . .
Revision history . . . . . . . . . . . . . . . . . . . . . . .
Legal information . . . . . . . . . . . . . . . . . . . . . .
Data sheet status . . . . . . . . . . . . . . . . . . . . . .
Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . .
Disclaimers . . . . . . . . . . . . . . . . . . . . . . . . . .
Trademarks . . . . . . . . . . . . . . . . . . . . . . . . . .
Contact information . . . . . . . . . . . . . . . . . . . .
Contents. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
30
30
30
31
31
31
33
35
35
37
38
38
40
46
47
47
47
47
47
48
49
49
50
50
50
50
51
51
52
Please be aware that important notices concerning this document and the product(s)
described herein, have been included in section ‘Legal information’.
© NXP B.V. 2010.
All rights reserved.
For more information, please visit: http://www.nxp.com
For sales office addresses, please send an email to: [email protected]
Date of release: 29 April 2010
Document identifier: SC16IS741_1
Similar pages