Colophon© 2020 Raspberry Pi (Trading) Ltd.
The documentation around the Raspberry Pi Compute Module 4 is licensed under a Creative Commons Attribution-
NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA).
build-date: 2020-10-17
build-version: githash: 8a1afbf-clean
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Raspberry Pi Compute Module 4 IO Board
Legal Disclaimer Notice 1
Table of ContentsColophon. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Legal Disclaimer Notice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1. CM4 Module Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.2. PSU input. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.3. Dual Full size HDMI 2.0 connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.4. Gigabit Ethernet RJ45. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.5. USB 2.0 Hub . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.6. Micro USB connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.7. Micro SD Card socket . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.8. PCIe Gen 2 x1 socket . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.9. Fan connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.10. Dual DSI display connectors ( 22pin 0.5mm pitch cable) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.11. Dual CSI-2 display connectors ( 22pin 0.5mm pitch cable). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.12. A Raspberry Pi HAT connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.13. Real Time Clock (RTC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.14. Jumpers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.15. LEDs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3. Mechanical Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
4. Circuit Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Raspberry Pi Compute Module 4 IO Board
Table of Contents 2
Chapter 1. IntroductionFigure 1. Render of the
Raspberry Pi Compute
Module 4 IO Board.
The Raspberry Pi Compute Module 4 IO Board (CM4IO) is designed to assist in the development of products that make
use of the Raspberry Pi Compute Module 4. The Raspberry Pi Compute Module 4 IO Board contains many of the
interfaces that the Raspberry Pi 4, Model B has, and for general usage you should refer to Raspberry Pi 4, Model B
documentation. The significant difference between CM4IO and Raspberry Pi 4, Model B is the addition of a single PCIe
socket. The CM4IO has been designed as both a reference design for CM4 or to be used directly as a product with the
possible addition of PCIe Cards and Raspberry Pi HATs.
Raspberry Pi Compute Module 4 IO Board
Chapter 1. Introduction 3
Chapter 2. Features• Accepts the complete range of CM4 modules
• External +12V PSU
• 2 × Full-size HDMI 2.0 connectors
• Gigabit Ethernet RJ45 with POE support
• 2 × USB 2 Socket, with header for two more sockets
• Micro USB socket for updating the CM4
• Micro SD Card socket for CM4Lite modules.
• PCIe Gen 2 socket
• Standard Fan connector
• External power connector (+5V, +12V)
• 2 × MIPI DSI display FPC connectors (22pin 0.5mm pitch cable)
• 2 × MIPI CSI-2 camera FPC connectors (22pin 0.5mm pitch cable)
• Raspberry Pi HAT connector
• RTC with Battery socket and ability to wake up CM4
• Jumpers to disable features, e.g Wireless, EEPROM writing
2.1. CM4 Module Connectors
The two CM4 module connectors are positioned so the onboard wireless antenna is at the edge of the board for best
wireless performance.
2.2. PSU input
The main PSU input (J19) is a 2.1mm DC tip positive +12V input. On board there is a +12V to +5V DC-DC converter to
power the CM4. There is also an on-board +12V to +3.3V DC-DC converter PSU which is only used for the PCIe slot. The
+12V input feeds the +12V PCIe slot, the external PSU connect and the FAN connector directly. If these aren’t being used
then a wider input supply is possible ( +7.5V to +26V).
With a +12V supply via the DC barrel jack the external PSU connector ( J20, +5V, +12V ) is ideal to connect to PCIe cards
that require external PSU. You should ensure that the PSUs aren’t over loaded. J20 Matting connector is known as "Berg"
Part number AMP / TE Connectivity 171822-4 or similar.
The exact current required from the +12V PSU is dependent on the application and what is connected to the Raspberry Pi
Compute Module 4 IO Board. It is recommended to budget 9W for the CM4.
2.3. Dual Full size HDMI 2.0 connectors
The CM4 does most of the interfacing required for the HDMI interface so that most signals are directly connected to the
CM4. HDMI connectors require a +5V supply, this is provided on the Raspberry Pi Compute Module 4 IO Board via a
current limited switch.
Raspberry Pi Compute Module 4 IO Board
2.1. CM4 Module Connectors 4
2.4. Gigabit Ethernet RJ45
The Raspberry Pi Compute Module 4 IO Board uses a standard 1:1 Ethernet magjack, which supports POE as well.
Additional ESD protection is provided on the Raspberry Pi Compute Module 4 IO Board as it is typically needed in POE
applications.
2.5. USB 2.0 Hub
The Raspberry Pi Compute Module 4 IO Board has an onboard USB 2.0 hub. This connects to the CM4 USB 2.0 port. Two
ports from the hub are connected to a connector. The two other ports are connected to a header, this header can be used
to provide two extra internal ports.
There is an internal current limit switch to provide VBUS to the USB connectors. The current limit is set to approximately
1.2A.
The USB interface is disabled to save power by default on the CM4 . To enable it you need to add the following to the
config.txt file :
dtoverlay=dwc2,dr_mode=host
2.6. Micro USB connector
The micro USB connector is designed to enable the CM4 to be updated via rpiboot. When a micro USB cable is plugged in
the USB hub is automatically disabled, so the CM4 USB 2.0 port becomes a USB device.
2.7. Micro SD Card socket
WARNING
For use only with CM4Lite modules
The micro SD Card socket is a PUSH-PUSH socket. To release the micro SD Card a gentle push on the micro SD Card will
enable it to be removed.
2.8. PCIe Gen 2 x1 socket
The PCIe socket is designed to take standard PC PCIe cards. You should ensure that there is a suitable OS driver for your
card.
The PCIe link on the Raspberry Pi 4, Model B is used for the USB 3.0 interface via the VLI805 XHCI controller. If the
application requires USB 3.0 interface then an external XHCI controller is required like the VLI805.
The PCIe link has been successfully used with an NVMe drive via a passive PCIe adaptor. Currently the CM4 bootloader
doesn’t support NVMe drives so you must boot via a different source.
If the application uses a standard PCIe card then it might be useful to have a small PCIe adapter to rotate the PCIe card
90degress to enable a more compact case.
Note the PCIe Interface doesn’t support MSI-X. Typically PCIe devices will fall back to MSI.
Raspberry Pi Compute Module 4 IO Board
2.4. Gigabit Ethernet RJ45 5
2.9. Fan connector
This connector supports standard +12V FANs with PWM drive and tacho output. An EMC2301 controls the fan via I2C.
Mating connector part number Molex 47054-1000 or similar. The +12V power for the fan comes from the +12V input and
isn’t regulated.
TIP
To enable the I2C bus to the fan controller you will need dtparam=i2c_vc=on set in config.txt . The fan controller then
will be on i2c-10 address 0x2f ( 7bit address)
2.10. Dual DSI display connectors ( 22pin 0.5mm pitch cable)
Both DSI interfaces ( 2 channel and 4 channel) are brought out to separate 22way 0.5mm pitch connectors. These
connectors are the same as on the existing CMIO board, NB they are different from the Raspberry Pi 4, Model B. If the
DSI0 interface ( 2 channel ) is used then the 2 jumpers on J6 must be fitted to route the I2C bus to the connector
2.11. Dual CSI-2 display connectors ( 22pin 0.5mm pitch cable)
Both CSI-2 interfaces ( 2 channel and 4 channel) are brought out to separate 22way 0.5mm pitch connectors. These
connectors are the same as on the existing CMIO board, NB they are different from the Raspberry Pi 4, Model B. If the
CSI0 interface ( 2 channel ) is used then the 2 jumpers on J6 must be fitted to route the I2C bus to the connector
2.12. A Raspberry Pi HAT connector
The Raspberry Pi Compute Module 4 IO Board has a standard Raspberry Pi 40 way HAT connector. The mounting holes
are also provided so that standard HATs may be used.
2.13. Real Time Clock (RTC)
A PCF85063AT RTC is provided on the Raspberry Pi Compute Module 4 IO Board. A battery socket is provided for a
CR2032 battery. On initial setup the CLKOUT of the RTC should be disabled to save power.
The alarm output of the RTC is used to wakeup the CM4 from a previous shutdown. If an alarm goes off during normal
operation the CM4 will be reset, this can be used as a watchdog timer if required.
TIP
To enable the I2C bus to the RTC you will need dtparam=i2c_vc=on set in config.txt . The RTC then will be on i2c-10
address 0x51 ( 7bit address)
2.14. Jumpers
R4/R5 Vref Voltage Selection
By default the Raspberry Pi Compute Module 4 IO Board sets the CM4 IO voltage to +3.3v via R5. Moving R5 to R4 sets
the IO voltage on the CM4 to +1.8v . Moving the resistor requires the use of the soldering iron. NB Only of R4 R5 must be
fitted at any one time.
Raspberry Pi Compute Module 4 IO Board
2.9. Fan connector 6
NOTE
J6 CSI0 DSI0 I2C enable
For the J6 jumpers, if either CSI0 or DSI0 it used then both jumpers must be fitted to route the I2C bus to the
connectors
Table 1. J2 jumpersPin Function
1-2 nRPIBOOT If fitted forces USB booting, it is useful if the eMMC becomes corrupted.
3-4 EEPROM_nWP If fitted write protects the EEPROM on the CM4
5 AIN1 MXL7704 analog input consult MXL7704 datasheet for details
6 AIN0 MXL7704 analog input consult MXL7704 datasheet for details
7 GND for AIN signals
8 SYNC_IN
9 SYNC_OUT
10 GND
11 TV_OUT
12 GND
13-14 Connect a push button to wake up the CM4 from low power mode. It can’t be used to shutdown the CM4.
Table 2. J3 ( not fitted
by default)Pin Function
1 WL_nDIS when connected to ground the wireless interface will be disabled
2 GND Ground
3 BT_nDIS when connected to ground the Bluetooth interface will be disabled
Table 3. J1( not fitted
by default)Pin Function
1 GLOBAL_EN
2 GND
3 RUN_PG
2.15. LEDs
Red LED
This LED duplicates the function of the RED LED on the Raspberry Pi 4, Model B
Green LED
This LED duplicates the function of the GREEN LED on the Raspberry Pi 4, Model B
Raspberry Pi Compute Module 4 IO Board
2.15. LEDs 7
Chapter 3. Mechanical DiagramFigure 2. Mechanical
diagram of the
Raspberry Pi Compute
Module 4 IO Board.
Raspberry Pi Compute Module 4 IO Board
Chapter 3. Mechanical Diagram 8
Chapter 4. Circuit Diagram
1 2 3 4 5 6
1 2 3 4 5 6
A
B
C
D
A
B
C
D
Date:KiCad E.D.A. kicad (5.99.0-3207-g147540b3b)
Rev: 1Size: A4Id: 1/7
Title: Compute Module 4 IO Board - Top LevelFile: CM4IOv5.kicad_schSheet: /
(c) Raspberry Pi Trading 2020
www.raspberrypi.org
PSUs
File: PSUs.kicad_sch
+5v
+12v
PCIe-connector
File: PCIe-routing.kicad_sch
PCIE_CLK_P
PCIE_CLK_N
PCIE_TX_P
PCIE_TX_N
PCIE_CLK_nREQ
PCIE_nRST
PCIE_RX_P
PCIE_RX_N
+12v
+5v
CM4_GPIO ( Ethernet, GPIO, SDCARD)
File: CM4_GPIO.kicad_sch
ID_
SC
ID_
SD
CA
M_
GP
IO
SC
L0
SD
A0
+5v
+3.3vnEXTRST
GLOBAL_EN
GP
IO_
VR
EF
TV
_OU
T
CM4_HighSpeed
File: CM4_HighSpeed.kicad_sch
USB2_N
USB2_P
ID_
SC
ID_
SD
CA
M_
GP
IO
SC
L0
SD
A0
+5v
PCIE_CLK_P
PCIE_CLK_N
PCIE_TX_P
PCIE_TX_N
PCIE_nRST
PCIE_RX_P
PCIE_RX_N
PCIE_CLK_nREQ
+3.3v
USBOTG_ID
GP
IO_
VR
EF
TV
_OU
T
RTC , Wakeup, FAN
File: RTC.kicad_sch
SCL
SDA
+5v
+3.3vGLOBAL_EN
+12v
USB2-HUB
File: USB2-HUB.kicad_sch
USB2_N
USB2_P+5v
+3.3v
nEXTRST
USBOTG
H6MountingHole
H8MountingHole
H4MountingHole
H3MountingHole
H2MountingHole
H1MountingHole
H5MountingHole
H7MountingHole
+3.3v
+3.3v
nEXTRST
+3.3v
+5v
+5v
+3.3v
+12v
+5v
nEXTRST
+5v
+12v+5v
+5v
+12v
Connectors-------EthernetSDCARD40way RPIJumpers
Connectors-------FANBattery
Connectors-------Dual USBmicroUSB
Connectors-------HDMI 0HDMI 1CSI 0CSI 1DSI 0DSI 1
Connector------PCIe x1
Connectors-------DC Barrel Jack4 pin power
Figure 3. Top level
1 2 3 4 5 6
1 2 3 4 5 6
A
B
C
D
A
B
C
D
Date:KiCad E.D.A. kicad (5.99.0-3207-g147540b3b)
Rev: 1Size: A4Id: 4/7
Title: Compute Module 4 IO Board - CM4 - HighspeedFile: CM4_HighSpeed.kicad_schSheet: /CM4_HighSpeed/
(c) Raspberry Pi Trading 2020
www.raspberrypi.org
GNDHigh Speed Serial
USB_OTG_ID 101PCIe_CLK_nREQ102
USB2_N 103Reserved104
USB2_P 105Reserved106
GND 107GND108
PCIe_nRST 109PCIe_CLK_P110
VDAC_COMP 111PCIe_CLK_N112
GND 113GND114
CAM1_D0_N 115PCIe_RX_P116
CAM1_D0_P 117PCIe_RX_N118
GND 119GND120
CAM1_D1_N 121PCIe_TX_P122
CAM1_D1_P 123PCIe_TX_N124
GND 125GND126
CAM1_C_N 127CAM0_D0_N128
CAM1_C_P 129CAM0_D0_P130
GND 131GND132
CAM1_D2_N 133CAM0_D1_N134
CAM1_D2_P 135CAM0_D1_P136
GND 137GND138
CAM1_D3_N 139CAM0_C_N140
CAM1_D3_P 141CAM0_C_P142
HDMI1_HOTPLUG 143GND144
HDMI1_SDA 145HDMI1_TX2_P146
HDMI1_SCL 147HDMI1_TX2_N148
HDMI1_CEC 149GND150
HDMI0_CEC 151HDMI1_TX1_P152
HDMI0_HOTPLUG 153HDMI1_TX1_N154
GND 155GND156
DSI0_D0_N 157HDMI1_TX0_P158
DSI0_D0_P 159HDMI1_TX0_N160
GND 161GND162
DSI0_D1_N 163HDMI1_CLK_P164
DSI0_D1_P 165HDMI1_CLK_N166
GND 167GND168
DSI0_C_N 169HDMI0_TX2_P170
DSI0_C_P 171HDMI0_TX2_N172
GND 173GND174
DSI1_D0_N 175HDMI0_TX1_P176
DSI1_D0_P 177HDMI0_TX1_N178
GND 179GND180
DSI1_D1_N 181HDMI0_TX0_P182
DSI1_D1_P 183HDMI0_TX0_N184
GND 185GND186
DSI1_C_N 187HDMI0_CLK_P188
DSI1_C_P 189HDMI0_CLK_N190
GND 191GND192
DSI1_D2_N 193DSI1_D3_N194
DSI1_D2_P 195DSI1_D3_P196
GND 197GND198
HDMI0_SDA 199HDMI0_SCL200
Module1BComputeModule4
Hirose2off DF40C-100DS-0.4V
GND
R62.2K 1%
R72.2K 1%
1 2
3 4
J6THD-02-R
C13100n
IN1 OUT 2
GND3
U12RT9742SNGV
GND
SH
SH
2 SH
SH
3 SH
SH
4
D2+1
CK+10
CK
S11
CK-12
CEC13
UTILITY/HEAC+14
SCL15
SDA16
GN
D17
+5
V18
HPD/HEAC-19
D2S
2
D2-3
D1+4
D1S
5
D1-6
D0+7
D0S
8
D0-9
SH
SH
1
J22
690-019-298-412
GND
1
10
11
12
13
14
15
16
17
18
19
2
20
21
22
3
4
5
6
7
8
9
J5
Conn_01x22_Female
1
10
11
12
13
14
15
16
17
18
19
2
20
21
22
3
4
5
6
7
8
9
J4
Conn_01x22_Female
GND
SH
SH
2 SH
SH
3 SH
SH
4
D2+1
CK+10
CK
S11
CK-12
CEC13
UTILITY/HEAC+14
SCL15
SDA16
GN
D17
+5
V18
HPD/HEAC-19
D2S
2
D2-3
D1+4
D1S
5
D1-6
D0+7
D0S
8
D0-9
SH
SH
1
J10
690-019-298-412
1
10
11
12
13
14
15
16
17
18
19
2
20
21
22
3
4
5
6
7
8
9
J16
Conn_01x22_Female
1
10
11
12
13
14
15
16
17
18
19
2
20
21
22
3
4
5
6
7
8
9
J15
Conn_01x22_Female
GND
GND
GND
C12100n
GND GND GND
PCIE_TX_P
GPIO_VREF
PCIE_TX_N
SCL0
ID_SD
ID_SC
+5v
PCIE_CLK_nREQ
PCIE_CLK_P
PCIE_CLK_N
PCIE_RX_P
PCIE_RX_N
CAM_GPIO
SDA0
USBOTG_ID
+3.3v
USB2_N
USB2_P
TV_OUT
PCIE_nRST
HDMI1_SCL
CAM1_D0_P
CAM1_D1_N
CAM1_D1_P
CAM1_C_N
CAM1_D3_P
CAM1_D3_N
HDMI0_CEC
HDMI1_CEC
CAM0_D0_P
HDMI1_SDA
HDMI1_HOTPLUG
CAM1_D1_P
CAM1_D2_P
CAM1_D2_N
CAM1_C_P
CAM1_C_N
+3.3v
CAM_GPIO
CAM0_C_PCAM1_D0_P
CAM1_D1_N
SDA1
HDMI1_D2_P
HDMI1_D2_N
HDMI1_D1_P
SCL1
+3.3v
CAM1_D0_N
CAM1_C_P
HDMI_5v
CAM0_C_N
HDMI0_HOTPLUG
CAM0_D1_P
CAM0_D1_N
CAM1_D0_N
CAM0_D0_N HDMI0_D2_P
HDMI0_D2_N
HDMI0_D1_P
HDMI0_SCL
HDMI0_SDA
HDMI0_HOTPLUG
DSI0_D0_N
DSI0_D0_P
DSI0_D1_N
DSI0_D1_P
HDMI1_SDA
HDMI1_SCL
HDMI1_CEC
HDMI1_D1_N
HDMI_5v
HDMI0_D1_N
HDMI0_D0_P
HDMI0_D0_N
HDMI1_CK_N
HDMI1_CK_P
HDMI0_CK_P
HDMI0_CK_N
HDMI0_CEC
SDA1
SCL1
+3.3v
DSI1_D0_P
DSI1_D0_N
DSI1_D3_P
DSI1_D3_N
DSI1_D2_P
DSI1_D2_N
DSI1_C_P
DSI1_C_N
DSI1_D1_P
DSI1_D1_N
SDA1
SCL1
SDA0
SCL0
HDMI1_D2_N
HDMI1_D2_P
CAM0_C_P
+3.3v
DSI0_C_N
DSI0_C_P
HDMI1_HOTPLUG
HDMI1_D0_N
HDMI1_D0_P
HDMI0_CK_P
DSI1_C_P
DSI1_C_N
HDMI0_D0_P
HDMI0_D1_P
HDMI0_D1_N
HDMI0_D2_N
DSI0_D1_P
DSI0_D1_N
HDMI0_D0_N
DSI1_D2_N
HDMI0_CK_N
DSI1_D3_N
DSI1_D3_P
HDMI0_SCL
DSI1_D1_N
CAM_GPIO
SCL0
SDA0
CAM1_D3_P
HDMI0_D2_P
HDMI1_CK_P
HDMI1_CK_N
CAM0_C_N
CAM0_D1_P
HDMI1_D1_P
HDMI1_D1_N
HDMI1_D0_P
HDMI1_D0_N
CAM1_D2_P
CAM1_D3_N
HDMI_5v
DSI1_D1_P
CAM0_D0_N
CAM0_D0_P
CAM0_D1_N
HDMI0_SDA
DSI1_D2_P
ID_SC
DSI0_D0_N
GPIO_VREF
ID_SD
DSI0_D0_P
DSI1_D0_P
DSI1_D0_N
DSI0_C_P
DSI0_C_N
CAM1_D2_N
Camera Connectors Display Connectors
Jumpers to be fitted if Camera0 or Display0 are used.
Figure 4. CM4
Highspeed
Raspberry Pi Compute Module 4 IO Board
Chapter 4. Circuit Diagram 9
1 2 3 4 5 6
1 2 3 4 5 6
A
B
C
D
A
B
C
D
Date:KiCad E.D.A. kicad (5.99.0-3207-g147540b3b)
Rev: 1Size: A4Id: 5/7
Title: Compute Module 4 IO Board - GPIO - EthernetFile: CM4_GPIO.kicad_schSheet: /CM4_GPIO ( Ethernet, GPIO, SDCARD)/
(c) Raspberry Pi Trading 2020
www.raspberrypi.org
GND
1 2
3 4
J9THD-02-R
1000pF
75
C1
C2
C3
C4
C5
C6
C7
C8
GREEN
YELLOW
TRD0+1
TRD3-10
VC111
VC212
VC313
VC414
LEDY_A15
LEDY_K16
LEDG_A17
LEDG_K18
SHIELD19
TRD0-2
SHIELD20
TRD1+3
CT4
CT5
TRD1-6
TRD2+7
TRD2-8
TRD3+9
U3
MagJack-A70-112-331N126
R2470R
TP3TestPoint
R3
470R
C1100n
GND
D1LED Red
R17 nf
R18 nf
R4 nf
TP5
TestPoint
R5 0R
GND
GND
D2LED Green
1
2
3
J3Conn_01x03
1
2
3
J1Conn_01x03
1
10
11 12
13 14
2
3 4
5 6
7 8
9
J2Conn_02x07_Odd_Even
GND
OUT1
GND2
nFLG3 EN 4
IN 5
U18RT9742GGJ5
R2912K 1%
DAT21
DET_A10
SHIELD 11
DAT3/CD2
CMD3
VDD4
CLK5
VSS6
DAT07
DAT18
DET_B9
J7Micro_SD_Card_Det
2
GN
D3
4
VC
C5 U5
74LVC1G07SE-7
GND GND
GND
R101k
C510u
1
10
11 12
13 14
15 16
17 18
19
2
20
21 22
23 24
25 26
27 28
29
3
30
31 32
33 34
35 36
37 38
39
4
40
5 6
7 8
9
J8THD-20-R
D1+1
D1-2
GN
D3
D2+4
D2-5
U2TPD4EUSB30
R11k
GND
GND
GND
D1+1
D1-2
GN
D3
D2+4
D2-5
U1TPD4EUSB30
GND
2
GN
D3
4
VC
C5
U9
74LVC1G07SE-7
GND
GPIO
600mA Max
600mA Max
NB SD signals are only available
on modules without eMMC
GND 1
Ethernet_Pair0_N10
nEXTRST100
Ethernet_Pair2_P 11Ethernet_Pair0_P12
GND 13GND14
Ethernet_nLED3(3.3v) 15Ethernet_SYNC_IN(1.8v)16
Ethernet_nLED2(3.3v) 17Ethernet_SYNC_OUT(1.8v)18
Ethernet_nLED1(3.3v) 19
GND2
EEPROM_nWP20
PI_nLED_Activity 21GND22
GND 23GPIO2624
GPIO21 25GPIO1926
GPIO20 27GPIO1328
GPIO16 29
Ethernet_Pair3_P 3
GPIO630
GPIO12 31GND32
GND 33GPIO534
ID_SC 35ID_SD36
GPIO7 37GPIO1138
GPIO8 39
Ethernet_Pair1_P4
GPIO940
GPIO25 41GND42
GND 43GPIO1044
GPIO24 45GPIO2246
GPIO23 47GPIO2748
GPIO18 49
Ethernet_Pair3_N 5
GPIO1750
GPIO15 51GND52
GND 53GPIO454
GPIO14 55GPIO356
SD_CLK 57GPIO258
GND 59
Ethernet_Pair1_N6
GND60
SD_DAT3 61SD_CMD62
SD_DAT0 63SD_DAT564
GND 65GND66
SD_DAT1 67SD_DAT468
SD_DAT2 69
GND 7
SD_DAT770
GND 71SD_DAT672
SD_VDD_Override 73GND74
SD_PWR_ON 75Reserved76
+5v_(Input) 77GPIO_VREF(1.8v/3.3v_Input)78
+5v_(Input) 79
GND8
SCL080
+5v_(Input) 81SDA082
+5v_(Input) 83+3.3v_(Output)84
+5v_(Input) 85+3.3v_(Output)86
+5v_(Input) 87+1.8v_(Output)88
WL_nDisable 89
Ethernet_Pair2_N 9
+1.8v_(Output)90
BT_nDisable 91RUN_PG92
nRPIBOOT 93AnalogIP194
nPI_LED_PWR 95AnalogIP096
Camera_GPIO 97GND98
Global_EN 99
Module1AComputeModule4
GND
TV_OUT
ID_SC
GPIO_VREF
GLOBAL_EN
CAM_GPIO
+5v
SCL0
ID_SD
nEXTRST
SDA0
+3.3v
RUN_PG
GLOBAL_EN
GPIO23
TRD3_P
SD_DAT3
TRD3_NGPIO14
TRD1_N
SD_CMD
TRD1_P
SD_CLK
+3.3v
GPIO25
GPIO11
GPIO7
ID_SC
+3.3v
nPWR_LED
+1.8v
SD_DAT1
SD_DAT0
SD_DAT2
SD_PWR
SD_DET
SD_PWR_ON
GPIO24
SD_PWR
GPIO18
+3.3v
GPIO15
TR3_TAP
TR0_TAP
TRD1_P
TRD0_N
TRD0_P
TRD3_N
TRD3_P
TRD2_N
TRD2_P
TRD1_N
GPIO10
TR2_TAP
TR1_TAP
ETH_LEDY
TRD0_P
TRD0_N
TR1_TAP
TR0_TAPGPIO_VREF
+3.3v
+3.3v
TRD2_P
TRD2_N
TR3_TAP
TR2_TAP
+3.3v
+3.3v
+3.3v +5v
ETH_LEDG
GPIO2
GPIO3
GPIO4
GPIO13
GPIO9
GPIO17
GPIO27
GPIO22
WL_nDis
EEPROM_nWP
SYNC_OUT
GPIO26
SYNC_IN
TRD0_P
GPIO15
GPIO14
SD_CLK
SD_DAT3
SD_DAT0
SD_PWR_ON
+5v
GPIO6
GPIO18
GPIO23
GPIO24
GPIO25
GND
GPIO8
GPIO7
GPIO12
ID_SC
GPIO16
GPIO20
TV_OUT
AIN1
GPIO21
TRD3_N
TRD3_P
GPIO_VREF
ETH_LEDY
ETH_LEDG
TRD2_P
TRD2_N
+5v
RUN_PG
GPIO11
GPIO9
GPIO26
AIN0
RUN_PG
ID_SD
GPIO5
TRD0_N
TRD1_N
TRD1_P
GPIO13
SD_DAT1
SD_DAT2
GPIO19
GPIO3
GPIO17
nRPIBOOT
GLOBAL_EN
GPIO8
nPWR_LED
BT_nDis
nRPIBOOT
GPIO4
GPIO2
SYNC_IN
+3.3v
+1.8v
GLOBAL_EN
GPIO27
GPIO22
SD_DET
GPIO10
GPIO5
SYNC_OUT
ID_SD
GPIO19
GND
GPIO6
GND
SD_CMD
EEPROM_nWP
GND
GND
GPIO21
AIN0
GPIO20
GPIO16
GPIO12
AIN1
Ethernet POEProtection
40Way GPIO Header
PWR LED
GPIO Voltage select
POE Header
CM4Lite SDCARD I/F
If compute modules is awake RUN_PG will be high so the button doesn't do anythingIf the compute module is asleep then RUN_PG will be at 0v and so pull global enable low
A button bwteen pins 13-14 can be used to wake up compute module from power down
Not Fitted headers
EEPROM write protect = Jumper Pins 3-4
Activity LED
Force RPIBOOT = Jumper Pins 1-2
Ethernet
Figure 5. CM4 GPIO
1 2 3 4 5 6
1 2 3 4 5 6
A
B
C
D
A
B
C
D
Date:KiCad E.D.A. kicad (5.99.0-3207-g147540b3b)
Rev: 1Size: A4Id: 6/7
Title: Compute Module 4 IO Board - PCIeFile: PCIe-routing.kicad_schSheet: /PCIe-connector/
(c) Raspberry Pi Trading 2020
www.raspberrypi.org
C3210u
nPRSNT1 A1
+3.3V A10
nPERST A11
GND A12
REFCLK+ A13
REFCLK- A14
GND A15
PERP0 A16
PERN0 A17
GND A18
+12V A2
+12V A3
GND A4
TCK A5
TDI A6
TD0 A7
TMS A8
+3.3V A9
+12vB1
+3.3vAUXB10
nWAKEB11
nCLKREQB12
GNDB13
PETP0B14
PETN0B15
GNDB16
nPRSNT2B17
GNDB18
+12vB2
+12vB3
GNDB4
SMCLKB5
SMDATB6
GNDB7
+3.3vB8
nTRSTB9
J1210018783-11200TLF
GND
C26
10u 35v
C27
10u 35v
C25
10u 35v
C45100uF
C3310u
R2312K 1%
C65
nf
R3015K 1%
C3010u
C29
100n
GND
R2210R
C28
10u 35v C62
100n
C3110u
1 2
L3SRN6045TA-3R3Y
GND
R24
47K 1%
C64
1.2nF
GND GND
GND
BST1
VIN2
EN3
SS4 FB 5COMP 6
GND 7SW 8
EP
9
U15AP64501SP-13
TP1TestPoint
C63
nf
C44
10u 35v
C43
10u 35v
PCIE_CLK_N
PCIE_CLK_P
PCIE_nRST
PCIE_CLK_nREQ
PCIE_TX_N
+12v
PCIE_RX_N
PCIE_RX_P
+12v
PCIE_TX_P
+3.3v
+12v
+3.3v
+3.3v
+12v
NB PCIe x1 takes a maximum of +12v @0.6A or +3.3v@3A , 10Watts combined
PCIe x1 connector
3.3v @ 3.3A PSU for PCIe Only ( 12v Input )
TX and RX have PN swaps to improve routing
Figure 6. PCIe
Connector
Raspberry Pi Compute Module 4 IO Board
Chapter 4. Circuit Diagram 10
1 2 3 4 5 6
1 2 3 4 5 6
A
B
C
D
A
B
C
D
Date:KiCad E.D.A. kicad (5.99.0-3207-g147540b3b)
Rev: 1Size: A4Id: 2/7
Title: Compute Module 4 IO Board - USBFile: USB2-HUB.kicad_schSheet: /USB2-HUB/
(c) Raspberry Pi Trading 2020
www.raspberrypi.org
VBUS`
D-`
D+`
GND`
VBUS
D-
D+
GND
MT1
MT2
MT3
MT4
J13
690-008-221-904
GND GNDGND
GNDGND GND GND
C16100uF
GND
GND
GND
GND
Y124MHz
C827pF
GND
GND
R3615K 1%
GND
R1
436K
1%
C927pF
C610u
R1
336K
1%
GND
R1
236K
1%
R1
636K
1%
C3100n
C1010u
GND
GND
C7100n
IN1
GND2
EN3 nFault 4ILIM 5OUT 6
U7AP22653W6
GND
GND
GND
GND GND
C1710u
C2110u
VCC1
nOE10
SEL2
D_P3
D_N4
GND5
HSD0_M 6HSD0_P 7
HSD1_M 8HSD1_P 9
U13FSUSB42MUX
R82.2K 1%
GNDGND
C2010u
VBUS1
D-2D+3
ID4
GN
D5
Sh
ield
6
J11USB_OTG
GND
C1910u
R11
2.2K 1%
1
10
2
3 4
5 6
7 8
9
J14Conn_02x05_Odd_Even
C11100n
C15100n
C14100n
C4100n
C210u
D1+1
D1-2
GN
D3
D2+4
D2-5
U4TPD4EUSB30
USBDM_DN1/PRT_DIS_M1 1
VD
DA
33
10
TEST11
PRTPWR1/BC_EN1 12
OCS_N1 13
CRFILT14
VD
D33
15
PRTPWR2/BC_EN2 16
OCS_N2 17
PRTPWR3/BC_EN3 18
OCS_N3 19
USBDP_DN1/PRT_DIS_P1 2
PRTPWR4/BC_EN4 20
OCS_N4 21SDA/SMBDATA/NON_REM122
VD
D33
23
SCL/SMBCLK/CFG_SEL024
HS_IND/CFG_SEL125
RESET_N26
VBUS_DET27
SUSP_IND/LOCAL_PWR/NON_REM028
VD
DA
33
29
USBDM_DN2/PRT_DIS_M2 3
USBDM_UP30
USBDP_UP31
XTALOUT32XTALIN/CLKIN33
PLLFILT34
RBIAS35
VD
DA
33
36
VS
S37
USBDP_DN2/PRT_DIS_P2 4
VD
DA
33
5
USBDM_DN3/PRT_DIS_M3 6
USBDP_DN3/PRT_DIS_P3 7
USBDM_DN4/PRT_DIS_M4 8
USBDP_DN4/PRT_DIS_P4 9
U6USB2514B-I/M2
R1512K 1%
USB2_P
+3.3v
+5v
USB2_N
nEXTRST
USBOTG
nEXTRST
nOCS1
HD1_P
HD1_N
VBUS
HD3_P
HD3_N
USBH_P
USBH_N
+3.3v
USBD_N
USBD_P
HD4_N
HD2_N
HD2_P
nOCS1
HD1_P
nOCS1
PWR1
VBUS
HD2_N
HD2_P
HD4_P
+5v
VBUS
HD4_N
HD1_N
VBUS
+3.3v
HD4_P
PWR1 nOCS1
+3.3v
HD3_P
HD3_N
VBUS
USBD_N
USBD_P
nOCS1
If a cable in plugged into the uUSB socket the CM4 becomes a usb device
Expansion USB connector
Micro USB ESD protection
Stacked USB connectors
Current Limit switchUSB 2.0 Hub
Figure 7. USB2 Hub
1 2 3 4 5 6
1 2 3 4 5 6
A
B
C
D
A
B
C
D
Date:KiCad E.D.A. kicad (5.99.0-3207-g147540b3b)
Rev: 1Size: A4Id: 3/7
Title: Compute Module 4 IO Board - RTC - FANFile: RTC.kicad_schSheet: /RTC , Wakeup, FAN/
(c) Raspberry Pi Trading 2020
www.raspberrypi.org
2
GN
D3
4
VC
C5
U1474LVC1G07SE-7
GND
SDA1
SCL2
VDD3
GND4 PWM 5TACH 6
CLK 7nALERT 8
U11EMC2301-1-ACZL-TR
R21
36K 1%
Y2X32K768S301
C23100n
GND
GND
GND
OSCI1
OSCO2 ~INT~ 3
VS
S4
SDA 5SCL 6
CLKO 7
VD
D8
U8PCF85063AT/AAZ
R19
510K 1%
R20
510K 1%
1
2
3
4
J17
Molex 470531000
C22100n
C24100n
GND
C46100n
BT1Battery_Cell
GND
GND
12
3D3BAT54C-7-F
GND
+3.3v
GLOBAL_EN
+5vSDASCL
+12v
GLOBAL_ENnRTC_INT
+5v
nRTC_INT
+3.3v
+3.3v
+3.3v
SDA
SCL
SCL
SDA
IIC address : 0101_111x
FAN connector
IIC address : 1010_001x
FAN controler
RTC alarms can be used to wake up the Compute moduleNB an Alarm triggering while already awake will cause a resetThis can be used as a watchdog reset
GLOBAL_EN needs to be pulse low for >1mS
Also SMBUS alert IIC address : 0001_100x
The above circuit generates a pulse forGLOBAL_EN when nRTC_INT goes low
RTC and RTC wakeup
Figure 8. RTC Wakeup
FAN
Raspberry Pi Compute Module 4 IO Board
Chapter 4. Circuit Diagram 11
1 2 3 4 5 6
1 2 3 4 5 6
A
B
C
D
A
B
C
D
Date:KiCad E.D.A. kicad (5.99.0-3207-g147540b3b)
Rev:Size: A4Id: 7/7
Title: Compute Module 4 IO Board - PSUsFile: PSUs.kicad_schSheet: /PSUs/
(c) Raspberry Pi Trading 2020
www.raspberrypi.org
R2612K 1%
C35
10u 35v
C37
10u 35v
C34
10u 35v
C39
10u 35v
C38
10u 35v
C41
10u 35vC58
100n
GND
GND
GND
C40
100n
TP4
TestPoint
GND
1
4
5
Q1DMP3013SFV-7
1
2
3
J19Barrel_Jack
D4MMBZ5242BLT3G
C36
100n 100v
GND
1
2
3
4
J20
AMP171826-4
TP2TestPoint
C4210u 35v
GND
GND
C4710u
TP6TestPoint
GND
C5110u
R27
12K 1%
C61
nf
GND
C5210u
C18100uF
R282.2K 1%
C4910u
R2520K 1%
1 2
L5SRN6045TA-3R3Y
C60
1.2nF
BST1
VIN2
EN3
SS4 FB 5COMP 6
GND 7SW 8
EP
9
U16AP64501SP-13
C57
100n
C59
nf
R910R
+5v
+12v
+12v
+5v
+12v
+12v+5v
5v @ 3A PSU
Can be used to power other devices if total loading on PSUs aren't exceeded
4 pin Power connectoras found on Floppy drives
+12v Input
2.1mm Tip +ve
+5v @ 3A PSU ( 7.5v-28v Input )
Can be used to power the CM4IO board. NB +12v will also be available at the DC Jack
+12v is only needed for PCIe and the FAN. If these aren't used then +12v isn't needed
Ideal diode to prevent reversepolarity at the input
Figure 9. PSU
Raspberry Pi Compute Module 4 IO Board
Chapter 4. Circuit Diagram 12