MCS7840
USB-2.0 to Four Serial Ports
Page 4
Rev.
1.2
Pin Assignments
Pin
Name
Type
Functional Description
1
GND
K
Power
Core Ground
2
USB_XSCI
Input
Crystal Oscillator Input
3
USB_XSCO
Output
Crystal Oscillator Output
4
Vcc
A
Power
Power Pin (A3V3)
5
GND
A
Power
Analog Ground
6
USB_RREF
Input
External Reference Resistor (12.1 K
Ω, 1%)
Connect resistor to Analog GND.
7
USB_DM
I/O
USB D- Signal
8
USB_DP
I/O
USB D+ Signal
9
Vcc
A
Power
Power Pin (A3V3)
10
GND
A
Power
Analog Ground
11
Vcc
K
Power
Power Pin (1.8V)
12
TEST_MODE
Input
Test Mode Pin, (active high). Default = Low (0)
When TEST_MODE = 1, PLL, Core, and SCAN/BIST/
Memory BIST testing can be performed.
Set TEST_MODE = 0 for normal operation.
13
TXD_4
Output
Serial Port 4 Transmit Data out to transceiver or IrDA
data out to IR LED
14
DTR_4_N
Output
Serial Port 4 Data Terminal Ready (in serial protocol),
active low.
15
RTS_4_N
Output
Serial Port 4 Request To Send (in serial protocol),
active low.
16
RXD_4
Input
Serial Port 4 Serial Receive Data in from transceiver
or IrDA data in from IrDA detector.
17
RI_4_N
Input
Serial Port 4 Ring Indicator, active low
18
DSR_4_N
Input
Serial Port 4 Data Set Ready (in serial protocol), active
low
19
DCD_4_N
Input
Serial Port 4 Data Carrier Detect (in serial protocol),
active low
20
CTS_4_N
Input
Serial Port 4 Clear To Send (in serial protocol), active
low
21
TXD_1
Output
Serial Port 1 Transmit Data out to transceiver, or IrDA
data out to IR LED
22
DTR_1_N
Output
Serial Port 1 Data Terminal Ready (in serial protocol),
active low.
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