áç
ST16C650A
2.90V TO 5.5V UART WITH 32-BYTE FIFO
REV. 5.0.0
LCR[7]: Baud Rate Divisors Enable
Baud rate generator divisor (DLL/DLM) enable.
• Logic 0 = Data registers are selected (default).
• Logic 1 = Divisor latch registers are selected if
≠
.
LCR 0xBF
4.7
Modem Control Register (MCR) or General Purpose Outputs Control - Read/Write
The MCR register is used for controlling the serial/modem interface signals or general purpose inputs/outputs.
MCR[0]: DTR# Pins
The DTR# pin is a modem control output. If the modem interface is not used, this output may be used for
general purpose.
• Logic 0 = Force DTR# output to a logic 1 (default).
• Logic 1 = Force DTR# output to a logic 0.
MCR[1]: RTS# Pins
The RTS# pin is a modem control output and may be used for automatic hardware flow control enabled by
EFR bit-6. If the modem interface is not used, this output may be used for general purpose.
• Logic 0 = Force RTS# output to a logic 1 (default).
• Logic 1 = Force RTS# output to a logic 0.
MCR[2]: OP1# Output
OP1# is a general purpose output.
• Logic 0 = OP1# output is at logic 1 (default).
• Logic 1 = OP1# output is at logic 0
MCR[3]: OP2# or IRQn Enable during PC Mode
OP2# is a general purpose output available during the Intel or Motorola bus interface mode of operation. In the
PC bus mode, it enables the IRQn operation. See PC Mode section.
During Intel or Motorola Bus Mode Operation:
• Logic 0 = OP2# output is at logic 1 (default).
• Logic 1 = OP2# output is at logic 0.
During PC Mode Operation:
• Logic 0 = Disable IRQn operation (default).
• Logic 1 = Enable IRQn operation.
MCR[4]: Internal Loopback Enable
• Logic 0 = Disable loopback mode (default).
• Logic 1 = Enable local loopback mode, see loopback section and Figure 15.
MCR[5]: Active/Three-state Interrupt Output Enable
• Logic 0 = Enable active or three-state interrupt output (default).
• Logic 1 = Enable open source interrupt output mode. See Table 3 for detailed information.
31
EXAR [ EXAR CORPORATION ]
