SC26C92A1A NXP Semiconductors, SC26C92A1A Datasheet - Page 19

• Manufacturer Part Number: SC26C92A1A
• Description: IC, UART, DUAL, SMD, 26C92, PLCC44
• Manufacturer: NXP Semiconductors

Specifications of SC26C92A1A

• No. Of Channels: 2
• Supply Voltage Range: 4.5V To 5.5V
• Operating Temperature Range: -40°C To +85°C
• Digital Ic Case Style: PLCC
• No. Of Pins: 44
• Svhc: No SVHC (18-Jun-2010)
• Operating Temperature: RoHS Compliant
• Data Rate: 230.4Kilobaud
• Uart Features: Parity, Framing, & Overrun Error Detection, Start-End Break Interrupt/Status
• Rohs Compliant: Yes

Philips Semiconductors
CRA – Channel A Command Register
CRA is a register used to supply commands to Channel A. Multiple
commands can be specified in a single write to CRA as long as the
commands are non-conflicting, e.g., the ‘enable transmitter’ and
‘reset transmitter’ commands cannot be specified in a single
command word.
CRA[7:4] – Miscellaneous Commands
Execution of the commands in the upper four bits of this register
must be separated by 3 X1 clock edges. Other reads or writes
(including writes tot he lower four bits) may be inserted to achieve
this separation.
CRA[7:4] – Command
0000 No command.
0001 Reset MR pointer. Causes the Channel A MR pointer to point
0010 Reset receiver. Resets the Channel A receiver as if a
0011 Reset transmitter. Resets the Channel A transmitter as if a
0100 Reset error status. Clears the Channel A Received Break, Parity
0101 Reset Channel A break change interrupt. Causes the
0110 Start break. Forces the TxDA output Low (spacing). If the
0111 Stop break. The TxDA line will go High (marking) within two
1000 Assert RTSN. Causes the RTSN output to be asserted
1001 Negate RTSN. Causes the RTSN output to be negated
1010 Set Timeout Mode On. The receiver in this channel will
1011 Set MR pointer to ‘0’
1100 Disable Timeout Mode. This command returns control of the
1101 Not used.
1110 Power Down Mode On. In this mode, the DUART oscillator is
2000 Jan 31
Dual universal asynchronous receiver/transmitter (DUART)
to MR1.
hardware reset had been applied. The receiver is disabled
and the FIFO is flushed.
hardware reset had been applied.
Error, and Overrun Error bits in the status register (SRA[7:4]).
Used in character mode to clear OE status (although RB, PE
and FE bits will also be cleared) and in block mode to clear all
error status after a block of data has been received.
Channel A break detect change bit in the interrupt status
register (ISR[2]) to be cleared to zero.
transmitter is empty the start of the break condition will be
delayed up to two bit times. If the transmitter is active the
break begins when transmission of the character is
completed. If a character is in the TxFIFO, the start of the
break will be delayed until that character, or any other loaded
subsequently are transmitted. The transmitter must be
enabled for this command to be accepted.
bit times. TxDA will remain High for one bit time before the
next character, if any, is transmitted.
(Low).
(High).
restart the C/T as each receive character is transferred from
the shift register to the RxFIFO. The C/T is placed in the
counter mode, the START/STOP counter commands are
disabled, the counter is stopped, and the Counter Ready Bit,
ISR[3], is reset. (See also Watchdog timer description in the
receiver section.)
C/T to the regular START/STOP counter commands. It does
not stop the counter, or clear any pending interrupts. After
disabling the timeout mode, a ‘Stop Counter’ command
should be issued to force a reset of the ISR(3) bit.
stopped and all functions requiring this clock are suspended.
The execution of commands other than disable power down
mode (1111) requires a X1/CLK. While in the power down
mode, do not issue any commands to the CR except the
disable power down mode command. The contents of all
registers will be saved while in this mode. . It is
recommended that the transmitter and receiver be disabled
19
1111 Disable Power Down Mode. This command restarts the
CRA[3] – Disable Channel A Transmitter
This command terminates transmitter operation and reset the
TxDRY and TxEMT status bits. However, if a character is being
transmitted or if a character is in the TxFIFO when the transmitter is
disabled, the transmission of the character(s) is completed before
assuming the inactive state.
CRA[2] – Enable Channel A Transmitter
Enables operation of the Channel A transmitter. The TxRDY and
TxEMT status bits will be asserted if the transmitter is idle.
CRA[1] – Disable Channel A Receiver
This command terminates operation of the receiver immediately – a
character being received will be lost. The command has no effect
on the receiver status bits or any other control registers. If the
special multidrop mode is programmed, the receiver operates even
if it is disabled. See Operation section.
CRA[0] – Enable Channel A Receiver
Enables operation of the Channel A receiver. If not in the special
wakeup mode, this also forces the receiver into the search for
start-bit state.
CRB – Channel B Command Register
CRB is a register used to supply commands to Channel B. Multiple
commands can be specified in a single write to CRB as long as the
commands are non-conflicting, e.g., the ‘enable transmitter’ and
‘reset transmitter’ commands cannot be specified in a single
command word.
The bit definitions for this register are identical to the bit definitions
for CRA, with the exception of commands “Ex” and “Fx” which are
used for power downmode. These two commands are not used in
CRB. All other control actions that apply to CRA also apply to CRB.
SRA – Channel A Status Register
SRA[7] – Channel A Received Break
This bit indicates that an all zero character of the programmed
length has been received without a stop bit. Only a single FIFO
position is occupied when a break is received: further entries to the
FIFO are inhibited until the RxDA line returns to the marking state
for at least one-half a bit time two successive edges of the internal
or external 1X clock. This will usually require a high time of one
X1 clock period or 3 X1 edges since the clock of the controller
is not synchronous to the X1 clock.
When this bit is set, the Channel A ‘change in break’ bit in the ISR
(ISR[2]) is set. ISR[2] is also set when the end of the break
condition, as defined above, is detected.
The break detect circuitry can detect breaks that originate in the
middle of a received character. However, if a break begins in the
middle of a character, it must persist until at least the end of the next
character time in order for it to be detected.
This bit is reset by command 4 (0100) written to the command
register or by receiver reset.
prior to placing the DUART into power down mode. This
command is in CRA only.
oscillator. After invoking this command, wait for the oscillator
to start up before writing further commands to the CR. This
command is in CRA only. For maximum power reduction
input pins should be at V
SS
or V
DD
.
Product specification
SC26C92