SC16C852LIBS-G NXP Semiconductors, SC16C852LIBS-G Datasheet - Page 30

• Manufacturer Part Number: SC16C852LIBS-G
• Manufacturer: NXP Semiconductors

Specifications of SC16C852LIBS-G

• Number Of Channels: 2
• Transmitter And Receiver Fifo Counter: Yes
• Data Rate: 5Mbps
• Mounting: Surface Mount
• Pin Count: 32
• Operating Temperature (min): -40C
• Operating Temperature (max): 85C
• Operating Temperature Classification: Industrial
• Lead Free Status / Rohs Status: Compliant

NXP Semiconductors
SC16C852L
Product data sheet
7.4 Interrupt Status Register (ISR)
The SC16C852L provides six levels of prioritized interrupts to minimize external software
interaction. The Interrupt Status Register (ISR) provides the user with six interrupt status
bits. Performing a read cycle on the ISR will provide the user with the highest pending
interrupt level to be serviced. No other interrupts are acknowledged until the pending
interrupt is serviced. A lower level interrupt may be seen after servicing the higher level
interrupt and re-reading the interrupt status bits.
data values (bits 5:0) for the six prioritized interrupt levels and the interrupt sources
associated with each of these interrupt levels.
Table 15.
Table 16.
Priority
level
1
2
2
3
4
5
6
Bit
7:6
5:4
3:1
0
Symbol
ISR[7:6]
ISR[5:4]
ISR[3:1]
ISR[0]
ISR[5]
0
0
0
0
0
0
1
Interrupt source
Interrupt Status Register bits description
All information provided in this document is subject to legal disclaimers.
ISR[4]
0
0
0
0
0
1
0
FIFOs enabled. These bits are set to a logic 0 when the FIFOs are not being
INT priority bits 4:3. These bits are enabled when EFR[4] is set to a logic 1.
INT priority bits 2:0. These bits indicate the source for a pending interrupt at
INT status.
Description
used in the non-FIFO mode. They are set to a logic 1 when the FIFOs are
enabled in the SC16C852L mode.
ISR[4] indicates that matching Xoff character(s) have been detected. ISR[5]
indicates that CTS, RTS have been generated. Note that once set to a
logic 1, the ISR[4] bit will stay a logic 1 until Xon character(s) are received.
interrupt priority levels 1, 2, and 3 (see
1.8 V dual UART with 128-byte FIFOs and IrDA encoder/decoder
Rev. 4 — 1 February 2011
logic 0 or cleared = default condition
logic 0 or cleared = default condition
logic 0 or cleared = default condition
logic 0 = an interrupt is pending and the ISR contents may be used as a
pointer to the appropriate interrupt service routine
logic 1 = no interrupt pending (normal default condition)
ISR[3]
0
0
1
0
0
0
0
ISR[2]
1
1
1
0
0
0
0
ISR[1]
1
0
0
1
0
0
0
Table 15 “Interrupt source”
ISR[0]
0
0
0
0
0
0
0
Table
Source of the interrupt
LSR (Receiver Line Status
Register)
RXRDY (Received Data Ready)
RXRDY (Receive Data time-out)
TXRDY (Transmitter Holding
Register Empty)
MSR (Modem Status Register)
RXRDY (Received Xoff signal)/
Special character
CTS, RTS change of state
15).
SC16C852L
© NXP B.V. 2011. All rights reserved.
shows the
30 of 64