.hide-partial { max-height: none; } .show-more { display: none; }

Silicon Labs Microcontrollers - MCU

.catnav-wrapper { height: auto; overflow: visible; } .catalog-nav-tabs ul { white-space: normal; }

Types of Microcontrollers - MCU

List Images

Results: 1,234

Applied Filters:

Manufacturer = Silicon Labs

Mounting Style

Package / Case

Core

Data Bus Width

Maximum Clock Frequency

Program Memory Size

Data RAM Size

ADC Resolution

Number of I/Os

Supply Voltage - Min

Supply Voltage - Max

Maximum Operating Temperature

Qualification

Packaging

Reset All

Search within results

In Stock

Normally Stocked

Active

New Products

RoHS Compliant

.search-refine-wrapper { display: inline-block; min-width: 100%; } .scroll-body { overflow-x: visible; } .search-table-wrapper { overflow: visible; } .hide-partial { max-height: none; } .show-more { display: none; }

Part #

ARM Microcontrollers - MCU ARM Cortex -M0+ Zero Gecko Microcontroller IC 32-Bit 24MHz 8KB Flash QFN24

EFM32ZG108F8-B-QFN24R
Silicon Labs
1,000: ¥264.1
Non-Stocked Lead-Time 12 Weeks

Mfr. Part #
EFM32ZG108F8-B-QFN24R

Mouser Part #
634-EFM32ZG108F8B24R

Silicon Labs

ARM Microcontrollers - MCU ARM Cortex -M0+ Zero Gecko Microcontroller IC 32-Bit 24MHz 8KB Flash QFN24

Learn More

Datasheet

Non-Stocked Lead-Time 12 Weeks

Reel

¥264.1

¥260.8

¥259.1

Min.: 1,000
Mult.: 1,000

: 1,000

SMD/SMT

QFN-24

ARM Cortex M0+

32 bit

24 MHz

8 kB

2 kB

12 bit

1.98 V

3.8 V

+ 85 C

Reel

ARM Microcontrollers - MCU ARM Cortex -M0+ Zero Gecko Microcontroller IC 32-Bit 24MHz 16KB Flash QFN24

EFM32ZG110F16-B-QFN24
Silicon Labs
2,450: ¥297.3
Non-Stocked Lead-Time 12 Weeks

Mfr. Part #
EFM32ZG110F16-B-QFN24

Mouser Part #
634-EFM32ZG110F16B24

Silicon Labs

ARM Microcontrollers - MCU ARM Cortex -M0+ Zero Gecko Microcontroller IC 32-Bit 24MHz 16KB Flash QFN24

Learn More

Datasheet

Non-Stocked Lead-Time 12 Weeks

¥297.3

Min.: 2,450
Mult.: 2,450

SMD/SMT

QFN-24

ARM Cortex M0+

32 bit

24 MHz

16 kB

4 kB

12 bit

17 I/O

1.98 V

3.8 V

+ 85 C

Tray

ARM Microcontrollers - MCU ARM Cortex -M0+ Zero Gecko Microcontroller IC 32-Bit 24MHz 4KB Flash QFN24

EFM32ZG110F4-B-QFN24
Silicon Labs
2,450: ¥272.4
Non-Stocked Lead-Time 12 Weeks

Mfr. Part #
EFM32ZG110F4-B-QFN24

Mouser Part #
634-EFM32ZG110F4B-24

Silicon Labs

ARM Microcontrollers - MCU ARM Cortex -M0+ Zero Gecko Microcontroller IC 32-Bit 24MHz 4KB Flash QFN24

Learn More

Datasheet

Non-Stocked Lead-Time 12 Weeks

¥272.4

Min.: 2,450
Mult.: 2,450

SMD/SMT

QFN-24

ARM Cortex M0+

32 bit

24 MHz

4 kB

2 kB

12 bit

17 I/O

1.98 V

3.8 V

+ 85 C

Tray

ARM Microcontrollers - MCU ARM Cortex -M0+ Zero Gecko Microcontroller IC 32-Bit 24MHz 4KB Flash QFN24

EFM32ZG110F4-B-QFN24R
Silicon Labs
1,000: ¥280.7
Non-Stocked Lead-Time 12 Weeks

Mfr. Part #
EFM32ZG110F4-B-QFN24R

Mouser Part #
634-EFM32ZG110F4B24R

Silicon Labs

ARM Microcontrollers - MCU ARM Cortex -M0+ Zero Gecko Microcontroller IC 32-Bit 24MHz 4KB Flash QFN24

Learn More

Datasheet

Non-Stocked Lead-Time 12 Weeks

Reel

¥280.7

¥275.7

¥272.4

Min.: 1,000
Mult.: 1,000

: 1,000

SMD/SMT

QFN-24

ARM Cortex M0+

32 bit

24 MHz

4 kB

2 kB

12 bit

1.98 V

3.8 V

+ 85 C

Reel

ARM Microcontrollers - MCU ARM Cortex -M0+ Zero Gecko Microcontroller IC 32-Bit 24MHz 8KB Flash QFN24

EFM32ZG110F8-B-QFN24
Silicon Labs
2,450: ¥285.7
Non-Stocked Lead-Time 12 Weeks

Mfr. Part #
EFM32ZG110F8-B-QFN24

Mouser Part #
634-EFM32ZG110F8B-24

Silicon Labs

ARM Microcontrollers - MCU ARM Cortex -M0+ Zero Gecko Microcontroller IC 32-Bit 24MHz 8KB Flash QFN24

Learn More

Datasheet

Non-Stocked Lead-Time 12 Weeks

¥285.7

Min.: 2,450
Mult.: 2,450

SMD/SMT

QFN-24

ARM Cortex M0+

32 bit

24 MHz

8 kB

2 kB

12 bit

17 I/O

1.98 V

3.8 V

+ 85 C

Tray

ARM Microcontrollers - MCU ARM Cortex -M0+ Zero Gecko Microcontroller IC 32-Bit 24MHz 8KB Flash QFN24

EFM32ZG110F8-B-QFN24R
Silicon Labs
1,000: ¥292.3
Non-Stocked Lead-Time 12 Weeks

Mfr. Part #
EFM32ZG110F8-B-QFN24R

Mouser Part #
634-EFM32ZG110F8B24R

Silicon Labs

ARM Microcontrollers - MCU ARM Cortex -M0+ Zero Gecko Microcontroller IC 32-Bit 24MHz 8KB Flash QFN24

Learn More

Datasheet

Non-Stocked Lead-Time 12 Weeks

Reel

¥292.3

¥289

¥285.7

Min.: 1,000
Mult.: 1,000

: 1,000

SMD/SMT

QFN-24

ARM Cortex M0+

32 bit

24 MHz

8 kB

2 kB

12 bit

1.98 V

3.8 V

+ 85 C

Reel

ARM Microcontrollers - MCU ARM Cortex -M0+ Zero Gecko Microcontroller IC 32-Bit 24MHz 16KB Flash QFN32

EFM32ZG210F16-B-QFN32R
Silicon Labs
3,000: ¥372.1
Non-Stocked Lead-Time 12 Weeks

Mfr. Part #
EFM32ZG210F16-B-QFN32R

Mouser Part #
634-EFM32ZG21016B32R

Silicon Labs

ARM Microcontrollers - MCU ARM Cortex -M0+ Zero Gecko Microcontroller IC 32-Bit 24MHz 16KB Flash QFN32

Learn More

Datasheet

Non-Stocked Lead-Time 12 Weeks

Reel

¥372.1

Min.: 3,000
Mult.: 3,000

: 3,000

SMD/SMT

QFN-32

ARM Cortex M0+

32 bit

24 MHz

16 kB

4 kB

12 bit

1.98 V

3.8 V

+ 85 C

Reel

ARM Microcontrollers - MCU ARM Cortex -M0+ Zero Gecko Microcontroller IC 32-Bit 24MHz 16KB Flash QFN32

EFM32ZG210F16-B-QFN32
Silicon Labs
2,450: ¥372.1
Non-Stocked Lead-Time 12 Weeks

Mfr. Part #
EFM32ZG210F16-B-QFN32

Mouser Part #
634-EFM32ZG210F16B32

Silicon Labs

ARM Microcontrollers - MCU ARM Cortex -M0+ Zero Gecko Microcontroller IC 32-Bit 24MHz 16KB Flash QFN32

Learn More

Datasheet

Non-Stocked Lead-Time 12 Weeks

¥372.1

Min.: 2,450
Mult.: 2,450

SMD/SMT

QFN-32

ARM Cortex M0+

32 bit

24 MHz

16 kB

4 kB

12 bit

24 I/O

1.98 V

3.8 V

+ 85 C

Tray

ARM Microcontrollers - MCU ARM Cortex -M0+ Zero Gecko Microcontroller IC 32-Bit 24MHz 4KB Flash QFN32

EFM32ZG210F4-B-QFN32
Silicon Labs
2,450: ¥313.9
Non-Stocked Lead-Time 12 Weeks

Mfr. Part #
EFM32ZG210F4-B-QFN32

Mouser Part #
634-EFM32ZG210F4B-32

Silicon Labs

ARM Microcontrollers - MCU ARM Cortex -M0+ Zero Gecko Microcontroller IC 32-Bit 24MHz 4KB Flash QFN32

Learn More

Datasheet

Non-Stocked Lead-Time 12 Weeks

¥313.9

Min.: 2,450
Mult.: 2,450

SMD/SMT

QFN-32

ARM Cortex M0+

32 bit

24 MHz

4 kB

2 kB

12 bit

24 I/O

1.98 V

3.8 V

+ 85 C

Tray

ARM Microcontrollers - MCU ARM Cortex -M0+ Zero Gecko Microcontroller IC 32-Bit 24MHz 4KB Flash QFN32

EFM32ZG210F4-B-QFN32R
Silicon Labs
3,000: ¥313.9
Non-Stocked Lead-Time 12 Weeks

Mfr. Part #
EFM32ZG210F4-B-QFN32R

Mouser Part #
634-EFM32ZG210F4B32R

Silicon Labs

ARM Microcontrollers - MCU ARM Cortex -M0+ Zero Gecko Microcontroller IC 32-Bit 24MHz 4KB Flash QFN32

Learn More

Datasheet

Non-Stocked Lead-Time 12 Weeks

Reel

¥313.9

Min.: 3,000
Mult.: 3,000

: 3,000

SMD/SMT

QFN-32

ARM Cortex M0+

32 bit

24 MHz

4 kB

2 kB

12 bit

1.98 V

3.8 V

+ 85 C

Reel

ARM Microcontrollers - MCU ARM Cortex -M0+ Zero Gecko Microcontroller IC 32-Bit 24MHz 8KB Flash QFN32

EFM32ZG210F8-B-QFN32
Silicon Labs
2,450: ¥328.9
Non-Stocked Lead-Time 12 Weeks

Mfr. Part #
EFM32ZG210F8-B-QFN32

Mouser Part #
634-EFM32ZG210F8B-32

Silicon Labs

ARM Microcontrollers - MCU ARM Cortex -M0+ Zero Gecko Microcontroller IC 32-Bit 24MHz 8KB Flash QFN32

Learn More

Datasheet

Non-Stocked Lead-Time 12 Weeks

¥328.9

¥325.6

Min.: 2,450
Mult.: 2,450

SMD/SMT

QFN-32

ARM Cortex M0+

32 bit

24 MHz

8 kB

2 kB

12 bit

24 I/O

1.98 V

3.8 V

+ 85 C

Tray

ARM Microcontrollers - MCU ARM Cortex -M0+ Zero Gecko Microcontroller IC 32-Bit 24MHz 8KB Flash QFN32

EFM32ZG210F8-B-QFN32R
Silicon Labs
3,000: ¥342.2
Non-Stocked Lead-Time 12 Weeks

Mfr. Part #
EFM32ZG210F8-B-QFN32R

Mouser Part #
634-EFM32ZG210F8B32R

Silicon Labs

ARM Microcontrollers - MCU ARM Cortex -M0+ Zero Gecko Microcontroller IC 32-Bit 24MHz 8KB Flash QFN32

Learn More

Datasheet

Non-Stocked Lead-Time 12 Weeks

Reel

¥342.2

Min.: 3,000
Mult.: 3,000

: 3,000

SMD/SMT

QFN-32

ARM Cortex M0+

32 bit

24 MHz

8 kB

2 kB

12 bit

1.98 V

3.8 V

+ 85 C

Reel

8-bit Microcontrollers - MCU 8051 25 MHz 16 kB flash 4 kB RAM 8-bit Sleepy Bee MCU

EFM8SB20F16G-B-QFN24R
Silicon Labs
1,500: ¥187.7
Non-Stocked Lead-Time 12 Weeks

Mfr. Part #
EFM8SB20F16G-B-QFN24R

Mouser Part #
634-EFM8SB16GBQFN24R

Silicon Labs

8-bit Microcontrollers - MCU 8051 25 MHz 16 kB flash 4 kB RAM 8-bit Sleepy Bee MCU

Learn More

Datasheet

Non-Stocked Lead-Time 12 Weeks

Reel

¥187.7

¥179.4

Min.: 1,500
Mult.: 1,500

: 1,500

SMD/SMT

CIP-51 8051

8 bit

25 MHz

16 kB

4.25 kB

10 bit

16 I/O

1.8 V

3.6 V

+ 85 C

Reel

8-bit Microcontrollers - MCU 8051 25 MHz 32 kB flash 4 kB RAM 8-bit Sleepy Bee MCU

EFM8SB20F32G-B-QFN24
Silicon Labs
1: ¥380.4
Non-Stocked Lead-Time 12 Weeks

Mfr. Part #
EFM8SB20F32G-B-QFN24

Mouser Part #
634-EFM8SBF32GBQFN24

Silicon Labs

8-bit Microcontrollers - MCU 8051 25 MHz 32 kB flash 4 kB RAM 8-bit Sleepy Bee MCU

Learn More

Datasheet

Non-Stocked Lead-Time 12 Weeks

¥380.4

¥320.6

¥267.4

¥254.1

View

Min.: 1
Mult.: 1

SMD/SMT

QFN-24

CIP-51 8051

8 bit

25 MHz

32 kB

4.25 kB

10 bit

16 I/O

1.8 V

3.6 V

+ 85 C

Tube

ARM Microcontrollers - MCU Secure Vault High, 3200k Flash, 512k RAM, 20-bit ADC, QFN48

EFM32PG26B501F3200IM48-B
Silicon Labs
2,450: ¥883.7
Non-Stocked Lead-Time 12 Weeks

Mfr. Part #
EFM32PG26B501F3200IM48-B

Mouser Part #
634-EMPG26B501IM48

Silicon Labs

ARM Microcontrollers - MCU Secure Vault High, 3200k Flash, 512k RAM, 20-bit ADC, QFN48

Learn More

Datasheet

Non-Stocked Lead-Time 12 Weeks

¥883.7

Min.: 2,450
Mult.: 2,450

SMD/SMT

QFN-48

ARM Cortex M33

32 bit

80 MHz

3.13 MB

512 kB

12 bit, 16 bit, 20 bit

28 I/O

1.71 V

3.8 V

+ 125 C

Tray

ARM Microcontrollers - MCU Secure Vault High, 3200k Flash, 512k RAM, 20-bit ADC, QFN48

EFM32PG26B501F3200IM48-BR
Silicon Labs
2,500: ¥883.7
Non-Stocked Lead-Time 12 Weeks

Mfr. Part #
EFM32PG26B501F3200IM48-BR

Mouser Part #
634-EMPG26B501IM48R

Silicon Labs

ARM Microcontrollers - MCU Secure Vault High, 3200k Flash, 512k RAM, 20-bit ADC, QFN48

Learn More

Datasheet

Non-Stocked Lead-Time 12 Weeks

Reel

¥883.7

Min.: 2,500
Mult.: 2,500

: 2,500

SMD/SMT

QFN-48

ARM Cortex M33

32 bit

80 MHz

3.13 MB

512 kB

12 bit, 16 bit, 20 bit

28 I/O

1.71 V

3.8 V

+ 125 C

Reel

ARM Microcontrollers - MCU Secure Vault High, 3200k Flash, 512k RAM, 20-bit ADC, QFN68

EFM32PG26B501F3200IM68-B
Silicon Labs
1,300: ¥938.5
Non-Stocked Lead-Time 12 Weeks

Mfr. Part #
EFM32PG26B501F3200IM68-B

Mouser Part #
634-EMPG26B501IM68

Silicon Labs

ARM Microcontrollers - MCU Secure Vault High, 3200k Flash, 512k RAM, 20-bit ADC, QFN68

Learn More

Datasheet

Non-Stocked Lead-Time 12 Weeks

¥938.5

Quote

Min.: 1,300
Mult.: 1,300

SMD/SMT

QFN-68

ARM Cortex M33

32 bit

80 MHz

3.13 MB

512 kB

12 bit, 16 bit, 20 bit

48 I/O

1.71 V

3.8 V

+ 125 C

Tray

ARM Microcontrollers - MCU Secure Vault High, 3200k Flash, 512k RAM, 20-bit ADC, QFN68

EFM32PG26B501F3200IM68-BR
Silicon Labs
2,500: ¥895.3
Non-Stocked Lead-Time 12 Weeks

Mfr. Part #
EFM32PG26B501F3200IM68-BR

Mouser Part #
634-EMPG26B501IM68R

Silicon Labs

ARM Microcontrollers - MCU Secure Vault High, 3200k Flash, 512k RAM, 20-bit ADC, QFN68

Learn More

Datasheet

Non-Stocked Lead-Time 12 Weeks

Reel

¥895.3

Min.: 2,500
Mult.: 2,500

: 2,500

SMD/SMT

QFN-68

ARM Cortex M33

32 bit

80 MHz

3.13 MB

512 kB

12 bit, 16 bit, 20 bit

48 I/O

1.71 V

3.8 V

+ 125 C

Reel

ARM Microcontrollers - MCU Secure Vault High, 3200k Flash, 512k RAM, 20-bit ADC, QFN48, MVP

EFM32PG26B500F3200IM48-BR
Silicon Labs
2,500: ¥920.2
Non-Stocked Lead-Time 12 Weeks

Mfr. Part #
EFM32PG26B500F3200IM48-BR

Mouser Part #
634-EMPG26B5IM48R

Silicon Labs

ARM Microcontrollers - MCU Secure Vault High, 3200k Flash, 512k RAM, 20-bit ADC, QFN48, MVP

Learn More

Datasheet

Non-Stocked Lead-Time 12 Weeks

Reel

¥920.2

Min.: 2,500
Mult.: 2,500

: 2,500

SMD/SMT

QFN-48

ARM Cortex M33

32 bit

80 MHz

3.13 MB

512 kB

12 bit, 16 bit, 20 bit

28 I/O

1.71 V

3.8 V

+ 125 C

Reel

ARM Microcontrollers - MCU Secure Vault High, 3200k Flash, 512k RAM, 20-bit ADC, QFN68, MVP

EFM32PG26B500F3200IM68-BR
Silicon Labs
2,500: ¥931.8
Non-Stocked Lead-Time 12 Weeks

Mfr. Part #
EFM32PG26B500F3200IM68-BR

Mouser Part #
634-EMPG26B5IM68R

Silicon Labs

ARM Microcontrollers - MCU Secure Vault High, 3200k Flash, 512k RAM, 20-bit ADC, QFN68, MVP

Learn More

Datasheet

Non-Stocked Lead-Time 12 Weeks

Reel

¥931.8

Min.: 2,500
Mult.: 2,500

: 2,500

SMD/SMT

QFN-68

ARM Cortex M33

32 bit

80 MHz

3.13 MB

512 kB

12 bit, 16 bit, 20 bit

48 I/O

1.71 V

3.8 V

+ 125 C

Reel

32-bit Microcontrollers - MCU FG23L, 128kB Flash, 32kB RAM, +14 dBm, QFN40, -40 to +85 C

EFR32FG23L010F128GM40-CR
Silicon Labs
2,500: ¥342.2
Non-Stocked Lead-Time 12 Weeks
New Product

Mfr. Part #
EFR32FG23L010F128GM40-CR

Mouser Part #
634-F23L010F128GM40R

New Product

Silicon Labs

32-bit Microcontrollers - MCU FG23L, 128kB Flash, 32kB RAM, +14 dBm, QFN40, -40 to +85 C

Datasheet

Non-Stocked Lead-Time 12 Weeks

Reel

¥342.2

Min.: 2,500
Mult.: 2,500

: 2,500

SMD/SMT

QFN-40

128 kB

32 kB

+ 85 C

Reel

32-bit Microcontrollers - MCU FG23L, 128kB Flash, 32kB RAM, +20 dBm, QFN40, -40 to +85 C

EFR32FG23L020F128GM40-CR
Silicon Labs
2,500: ¥368.7
Non-Stocked Lead-Time 12 Weeks
New Product

Mfr. Part #
EFR32FG23L020F128GM40-CR

Mouser Part #
634-F23L020F128GM40R

New Product

Silicon Labs

32-bit Microcontrollers - MCU FG23L, 128kB Flash, 32kB RAM, +20 dBm, QFN40, -40 to +85 C

Datasheet

Non-Stocked Lead-Time 12 Weeks

Reel

¥368.7

Min.: 2,500
Mult.: 2,500

: 2,500

SMD/SMT

QFN-40

128 kB

32 kB

+ 85 C

Reel

8-bit Microcontrollers - MCU 8051 25 MHz 2 kB Flash 0.25 kB RAM 8-bit Busy Bee MCU

EFM8BB10F2A-A-QFN20
Silicon Labs
1: ¥411.9
Non-Stocked Lead-Time 12 Weeks

Mfr. Part #
EFM8BB10F2A-A-QFN20

Mouser Part #
634-FM8BB10F2AAQFN20

Silicon Labs

8-bit Microcontrollers - MCU 8051 25 MHz 2 kB Flash 0.25 kB RAM 8-bit Busy Bee MCU

Learn More

Datasheet

Non-Stocked Lead-Time 12 Weeks

¥411.9

¥347.1

¥304

¥284

View

Min.: 1
Mult.: 1

SMD/SMT

QFN-20

CIP-51 8051

8 bit

25 MHz

2 kB

256 B

12 bit

16 I/O

2.2 V

3.6 V

+ 125 C

AEC-Q100

Tube

ARM Microcontrollers - MCU ARM Cortex-M0+ 32-bit 25 MHz 64 kB MCU

EFM32HG108F64G-C-QFN24R
Silicon Labs
1,000: ¥370.4
Non-Stocked Lead-Time 12 Weeks

Mfr. Part #
EFM32HG108F64G-C-QFN24R

Mouser Part #
634-HG108F64GCQFN24R

Silicon Labs

ARM Microcontrollers - MCU ARM Cortex-M0+ 32-bit 25 MHz 64 kB MCU

Datasheet

Non-Stocked Lead-Time 12 Weeks

Reel

¥370.4

¥363.8

¥360.4

Min.: 1,000
Mult.: 1,000

: 1,000

SMD/SMT

QFN-24

ARM Cortex M0+

32 bit

25 MHz

64 kB

8 kB

12 bit

17 I/O

1.98 V

3.8 V

+ 85 C

Reel

ARM Microcontrollers - MCU ARM Cortex-M0+ 32-bit 25 MHz 64 kB MCU

EFM32HG110F64G-C-QFN24R
Silicon Labs
1: ¥727.5
Non-Stocked Lead-Time 12 Weeks

Mfr. Part #
EFM32HG110F64G-C-QFN24R

Mouser Part #
634-HG110F64GCQFN24R

Silicon Labs

ARM Microcontrollers - MCU ARM Cortex-M0+ 32-bit 25 MHz 64 kB MCU

Datasheet

Non-Stocked Lead-Time 12 Weeks

Cut Tape

¥727.5

¥594.6

¥546.5

¥486.7

Reel

¥393.7

View

Min.: 1
Mult.: 1

: 1,000

SMD/SMT

QFN-24

ARM Cortex M0+

32 bit

25 MHz

64 kB

8 kB

12 bit

17 I/O

1.98 V

3.8 V

+ 85 C

Reel, Cut Tape

BGA-112
BGA-120
BGA-125
BGA-136
BGA-152
BGA-192
BGA-48
CSP-16
CSP-81
LGA-42
LGA-85
LGA-92
LQFP-100
LQFP-32
MSOP-10
PQFP-48
QFN-11
QFN-12
QFN-16
QFN-20

8 B, 256 B, 4 kB
128 B
256 B
512 B
768 B
1 kB
1.25 kB
1.28 kB
1.54 kB
2 kB
2.25 kB
2.3 kB
2.31 kB
4 kB
4 kB, 256 B, 8 B
4.25 kB
4.35 kB
4352 B
8 kB
8.25 kB

5 I/O
6 I/O
8 I/O
9 I/O
11 I/O
12 I/O
13 I/O
15 I/O
16 I/O
17 I/O
18 I/O
20 I/O
21 I/O
22 I/O
24 I/O
25 I/O
26 I/O
28 I/O
29 I/O
32 I/O