Rainbow Electronics W90N740 User Manual
Page 168
W90N740
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TERI [2]: Tailing Edge of RI#
This bit is set whenever RI# input has changed from high to low, and it will be reset if the CPU reads the
MSR.
DDSR [1]: DSR# State Change
This bit is set whenever DSR# input has changed state, and it will be reset if the CPU reads the MSR.
DCTS [0]: CTS# State Change
This bit is set whenever CTS# input has changed state, and it will be reset if the CPU reads the MSR.
Whenever any of MSR [3:0] is set to logic 1, a Modem Status Interrupt is generated if IER[3]=1. Writing
MSR is a null operation (not suggested).
Time Out Register (TOR)
Register Address R/W
Description
Reset
Value
TOR
0xFFF8.001C R/W Time Out Register
0x0000.0000
7
6
5
4
3
2
1
0
TOIE TOIC
TOIE [7]: Time Out Interrupt Enable
The feature of receiver time out interrupt is enabled only when TOR [7] = IER[0] = 1.
TOIC [6:0]: Time Out Interrupt Comparator
The time out counter resets and starts counting (the counting clock = baud rate) whenever the RX FIFO
receives a new data word. Once the content of time out counter (TOUT_CNT) is equal to that of time out
interrupt comparator (TOIC), a receiver time out interrupt (Irpt_TOUT) is generated if TOR [7] = IER [0] =
1. A new incoming data word or RX FIFO empty clears Irpt_TOUT.