30 / 41 page

MCS7840
USB-2.0 to Four Serial Ports
Page 30
Rev.
1.2
Device Configuration Bit Fields and Descriptions
Bytes 4, 5, 6 and 22-30 form twenty-four 8-bit DCR Registers. These Bytes are read from the EEPROM, and
loaded into the Global Device Configuration Registers after Power-On Reset. They can be programmed by
software using the following application number and register indexes as shown in the table.
EEPROM
Location
DCR Bit
DCR Name
Application
Number
Register
Index
Default
Value
8
SER1_DCR[7:0]
SER1_DCR0
0
4
0x01
9
SER1_DCR[15:8]
SER1_DCR1
0
5
0x85
10
SER1_DCR[23:16]
SER1_DCR2
0
6
0x24
11
SER2_DCR[7:0]
SER2_DCR0
0
22
0x01
12
SER2_DCR[15:8]
SER2_DCR1
0
23
0x84
13
SER2_DCR[23:16]
SER2_DCR2
0
24
0x24
14
SER3_DCR[7:0]
SER3_DCR0
0
25
0x01
15
SER3_DCR[15:8]
SER3_DCR1
0
26
0x84
16
SER3_DCR[23:16]
SER3_DCR2
0
27
0x24
17
SER4_DCR[7:0]
SER4_DCR0
0
28
0x01
18
SER4_DCR[15:8]
SER4_DCR1
0
29
0x84
19
SER4_DCR[23:16]
SER4_DCR2
0
30
0x24
The following tables describe the function of each bit in the DCR registers. There are three DCR registers
for each Serial Port (IrDA). In the absence of an EEPROM, the default values are taken from the Device
Configuration Registers.