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
55
31
N/A
33
N/A
PB7 or
T2OUT
I/O
I
Multiplexed pin whose function is selected by the
(PB7) T2OUT bit of the PORTBCFG register. If T2OUT=0,
the pin is the bi-directional I/O port bit PB7. If
T2OUT=1, the pin is the active-high T2OUT signal
from 8051 Timer2.
T2OUT is active (high) for one clock cycle when
Timer/Counter 2 overflows.
30
31
32
33
38
39
14
15
16
17
18
19
14
15
16
17
18
19
16
17
18
19
20
21
16 PC0 or RXD0 I/O
I
Multiplexed pin whose function is selected by the
(PC0) RXD0 bit of the PORTCCFG register. If RXD0=0,
the pin is the bi-directional I/O port bit PC0. If
RXD0=1, the pin is the active-high RXD0 from 8051
UART0, which provides data to the UART in all
modes.
17
PC1 or TXD0 I/O
I
Multiplexed pin whose function is selected by the
(PC1) TXD0 bit of the PORTCCFG register. If TXD0=0,
the pin is the bi-directional I/O port bit PC1. If
TXD0=1, the pin is the active-high TXD0 signal for
8051 UART0, which provides the output clock in
sync mode, and the output data in async mode.
18 PC2 or INT0# I/O
I
Multiplexed pin whose function is selected by the
(PC2) INT0 bit of the PORTCCFG register. If INT0=0, the
pin is the bi-directional I/O port bit PC2. If INT0=1,
the pin is the active-low 8051 INT0 interrupt input
signal, which is either edge triggered (IT0=1) or level
triggered (IT0=0).
19 PC3 or INT1# I/O
I
Multiplexed pin whose function is selected by the
(PC3) INT1 bit of the PORTCCFG register. If INT1=0, the
pin is the bi-directional I/O port bit PC3. If INT1=1,
the pin is the active-low 8051 INT1 interrupt input
signal, which is either edge triggered (IT1=1) or level
triggered (IT1=0).
20
21
PC4 or T0
PC5 or T1
I/O
I/O
I
Multiplexed pin whose function is selected by the T0
(PC4) bit of the PORTCCFG register. If T0=0, the pin is
the bi-directional I/O port bit PC4. If T0=1, the pin is
the active-high T0 signal for 8051 Timer0, which pro-
vides the input to Timer0 when C/T0 is 1. When C/
T0 is 0, Timer0 does not use this bit.
I
Multiplexed pin whose function is selected by the T1
(PC5) bit of the PORTCCFG register. If T1=0, the pin is
the bi-directional I/O port bit PC5. If T1=1, the pin is
the active-high T1 signal from 8051 Timer1, which
provides the input to Timer1 when C/T1 is 1. When
C/T0 is 0, Timer1 does not use this bit.
EZ-USB TRM v1.9
Chapter 1. Introducing EZ-USB
Page 1-27
CYPRESS [ CYPRESS ]
