mcs7717 MosChip, mcs7717 Datasheet - Page 20

• Manufacturer Part Number: mcs7717
• Description: Three Port Usb Hub With 1 Serial, 1 Printer
• Manufacturer: MosChip

Page 20
MCS7717
Three Port USB Hub with 1 Serial, 1 Printer
FIFO Control Register:
The FCR controls the UART behavior in various modes.
Register:
Description:
Offset:
Permissions:
FCR[7:6] RHR Trigger Level:
In 550 mode, the receiver FIFO trigger levels are
defined using FCR[7:6]. The interrupt trigger level &
flow control trigger level where appropriate are defined
by L2 in the table below. L1 defines lower flow control
trigger levels that introduce a hysteresis element in
hardware RTS/CTS flow control.
In Byte Mode (450 Mode) the trigger levels are all set
to 1.
5, 4
7, 6
Bit
0
1
2
3
Bit[7]
Trigger Level
Trigger Level
FIFO Mode
Reserved
Reserved
RHR
Enable
Name
Flush
Flush
RHR
RHR
THR
FCR
FIFO Control Register
010
Write
Bit[6]
Logic 0 = Byte Mode
Logic 1 = FIFO Mode
Logic 0 = No change
Logic 1 = Flushes the contents of RHR. This is operative only in FIFO
Logic 0 = No change
Logic 1 = Flushes the content of the THR, in the same manner as FCR[1]
Reserved
Reserved
See the table below.
Bit[5]
Mode. The RHR is automatically flushed whenever changing
between Byte Mode and FIFO Mode. The bit will return to zero
after clearing the FIFOs.
does the RHR
Reserved
Bit[4]
Reserved
Bit[3]
Description
FCR[7:6]
2’b00
2’b01
2’b10
2’b11
Bit[2]
Flush
THR
L1
Bit[1]
Flush
RHR
1
1
1
1
(FIFO = 16)
550 Mode
Enable
Bit[0]
FIFO
Rev. 1.7
L2
14
1
4
8