mcs7840 MosChip, mcs7840 Datasheet - Page 10

• Manufacturer Part Number: mcs7840
• Description: Usb-2.0 To Four Serial Ports
• Manufacturer: MosChip

Page 10
MCS7840
USB-2.0 to Four Serial Ports
Transmitter Holding Register & Receiver Holding Register (THR & RHR):
Data is written into the bottom of the THR queue & read from the top of the RHR queue completely
asynchronously to the operation of the transmitter & receiver. The size of the FIFOs is dependent upon the
setting of the FCR register.
Data written to the THR when it is full, is lost. Data read from the RHR when it is empty, is invalid. The empty
and full status of the FIFOs is indicated in the Line Status Register.
Register:
Description:
Offset:
Permissions:
Access Condition:
Default Value:
Register:
Description:
Offset:
Permissions:
Access Condition:
Default Value:
Bit[7]
Bit[7]
THR
Data to be transmitted
0
Write Only
LCR[7] = 0
(unknown) – based on memory
RHR
Data to be received
0
Read Only
LCR[7] = 0
(unknown) – based on memory
Bit[6]
Bit[6]
Bit[5]
Bit[5]
Data to be transmitted
Data to be received
Bit[4]
Bit[4]
Bit[3]
Bit[3]
Bit[2]
Bit[2]
Bit[1]
Bit[1]
Rev.
Bit[0]
Bit[0]
1.2