Table 1-3. EZ-USB Series 2100 Pinouts by Pin Function
2125S
2126S
2135S
2136S
2121S
2131Q 2122S
2131S
2122T 2126T
Name
Type Default
Description
44
24
N/A
26
N/A
PB0 or T2
I/O
I
Multiplexed pin whose function is selected by the T2
(PB0) bit of the PORTBFCG register. If T2=0, the pin is the
bi-directional I/O port bit PB0. If T2=1, the pin is the
active-high T2 signal from 8051 Timer2, which pro-
vides the input to Timer2 when C/T2=1. When
C/T2=0, Timer2 does not use this pin.
45
46
25
26
N/A
N/A
27
28
N/A PB1 or T2EX I/O
N/A PB2 or RXD1 I/O
I
Multiplexed pin whose function is selected by the
(PB1) T2EX bit of the PORTBCFG register. If T2EX=0, the
pin is the bi-directional I/O port bit PB1. If T2EX=1,
the pin is the active-high T2EX signal from 8051
Timer2.
I
Multiplexed pin whose function is selected by the
(P{B2) RXD1 bit of the PORTBCFG register. If RXD1=0,
the pin is the bi-directional I/O port bit PB2. If
RXD1=1, the pin is the active-high RXD1 input sig-
nal for 8051 UART1, which provides data to the
UART in all modes.
47
27
N/A
29
N/A PB3 or TXD1 I/O
I
Multiplexed pin whose function is selected by the
(PB3) TXD1 bit of the PORTBCFG register. If TXD1=0, the
pin is the bi-directional I/O port bit PB3. If TXD1=1,
the pin is the active-high TXD1 output pin for 8051
UART1 which provides the output clock in sync
mode and the output data in async mode.
52
53
54
28
29
30
N/A
N/A
N/A
30
31
32
N/A PB4 or INT4
I/O
I
Multiplexed pin whose function is selected by the
(PB4) INT4 bit of the PORTBCFG register. If INT4=0, the
pin is the bi-directional I/O port bit PB4. If INT4=1,
the pin is the 8051 INT4 interrupt request signal.
The INT4 pin is edge-sensitive, active high.
N/A PB5 or INT5# I/O
I
Multiplexed pin whose function is selected by the
(PB5) INT5 bit of the PORTBCFG register. If INT5=0, the
pin is the bi-directional I/O port bit PB5. If INT5=1,
the pin is the INT5# interrupt register signal. The
INT5# pin is edge-sensitive, active low.
N/A PB6 or INT6
I/O
I
Multiplexed pin whose function is selected by the
(PB6) INT6 bit of the PORTBCFG register. If INT6=0, the
pin is the bi-directional I/O port bit PB6. If INT6=1,
the pin is the INT6 interrupt request signal. The
INT6 pin is edge-sensitive, active high.
Page 1-26
Chapter 1. Introducing EZ-USB
EZ-USB TRM v1.9
CYPRESS [ CYPRESS ]
