F81866A Datasheet, PDF (109/210 Pages) Feature Integration Technology Inc. – 6 UARTs Super IO With 128 Bytes FIFO and Power

6.8.5PWOK Signals
VDD3VOK
ATXPWGD
DELAY
F81866A
PWOK
Fig 6-24
PWOK is delayed 400ms (default) as VCC arrives 2.8V, and the delay timing can be programmed via
register (100ms ~ 400ms).
6.9 UART
The F81866A provides up to 6 UART ports and supports IRQ sharing for system application. They are
compatible with 16C550/16C650/16C750 and 16C850 .The UARTs are used to convert data between parallel
format and serial format. They convert parallel data into serial format on transmission and serial format into
parallel data on receiver side. The serial format is formed by one start bit, followed by five to eight data bits, a
parity bit if programmed and one ( 1.5 or 2 ) stop bits. The UARTs include complete modem control capability
and an interrupt system that may be software trailed to the computing time required to handle the communication
link. They have FIFO mode to reduce the number of interrupts presented to the host. Both receiver and
transmitter have a 128-byte FIFO.
The UART control register control & define the asynchronous protocol data communications including data
length, stop bit, parity & baud rate selection.
The below content is about the UARTs device register descriptions. All the registers are for software porting
reference.
6.9.1UART Device Register
Receiver Buffer Register ⎯ Base + 0
Bit
Name
R/W Reset Default
Description
7-0
RBR
The data received.
R LRESET# 00h _{Read only when LCR [7] is 0}
Transmitter Holding Register ⎯ Base + 0
Bit
Name
R/W Reset Default
Description
7-0
THR
Data to be transmitted.
W LRESET# 00h _{Write only when LCR [7] is 0}
109
Jan, 2012
V0. 12P