# Common Resources # Internal Communication Lines The device is equipped with multiple internal communication lines of the following types: - [{{@134#bkmrk-spi}}](https://doc.redisage.com/link/134#bkmrk-spi) - [{{@134#bkmrk-i2c}}](https://doc.redisage.com/link/134#bkmrk-i2c) - [{{@134#bkmrk-uart}}](https://doc.redisage.com/link/134#bkmrk-uart) ### SPI The device is equipped with the following SPI communication lines. #### SPI1

Signal	Processor pin	Default function
Chip select 0	AD18	SPI1\_CS0
Chip select 1	AG23	SPI1\_CS1
Master in slave out	A7	SPI1\_MISO
Clock	D6	SPI1\_SCLK
Master out slave in	B7	SPI1\_MOSI

#### SPI2

Signal	Processor pin	Default function
Chip select 0	A6	SPI2\_CS0
Chip select 1	AF12	SPI2\_CS1
Chip select 2	AB19	SPI2\_CS2
Master in slave out	A8	SPI2\_MISO
Clock	E6	SPI2\_SCLK
Master out slave in	B8	SPI2\_MOSI

### I2C The device is equipped with the following I2C communication lines. #### I2C2 Device name: **/dev/i2c-1**

Signal	Processor pin	Default function
Clock	D10	I2C2\_SCL
Data	D9	I2C2\_SDA

#### I2C3 Device name: **/dev/i2c-2**

Signal	Processor pin	Default function
Clock	E10	I2C3\_SCL
Data	F10	I2C3\_SDA

#### I2C4 Device name: **/dev/i2c-3**

Signal	Processor pin	Default function
Clock	D13	I2C4\_SCL
Data	E13	I2C4\_SDA

### UART The device is equipped with the following UART communication lines. #### UART1 Device name: **/dev/ttymxc0**

Signal	Processor pin	Default function
Receive (UART1 RX)	E14	UART1\_RXD
Transmit (UART1 TX)	F13	UART1\_TXD

#### UART2 Device name: **/dev/ttymxc1**

Signal	Processor pin	Default function
Receive (UART2 RX)	X	UART2\_RXD
Transmit (UART2 TX)	X	UART2\_TXD

#### UART3 Device name: **/dev/ttymxc2**

Signal	Processor pin	Default function
Receive (UART3 RX)	E18	UART3\_RXD
Transmit (UART3 TX)	D18	UART3\_TXD

#### UART4 Device name: **/dev/ttymxc3**

Signal	Processor pin	Default function
Receive (UART4 RX)	F19	UART4\_RXD
Transmit (UART4 TX)	F18	UART4\_TXD

# New Page # New Page # New Page # Introduction ## Tiger City IMX Industrial Computer with Linux OS The Tiger City IMX minicomputer uses Linux operating systems and is equipped with several communication interfaces such as: Ethernet, USB 2.0, HDMI, GSM, RS232, RS485, 1-Wire and multiple analog-digital inputs and outputs. It can also be configured to include a Wi-Fi module and encryption modules that increase the security of the device. The casing enables installation on the DIN rail. The front panel has switches, an OLED display and a joystick for manual control of the device operation. # Drawings ### Placement of peripherals

### Power supply

### Detailed connections diagram

### Enclosure [![image.png](https://doc.redisage.com/uploads/images/gallery/2026-01/scaled-1680-/image.png)](https://doc.redisage.com/uploads/images/gallery/2026-01/image.png) # CM Variscite Computation Module ### VAR-SOM-MX8MM Table of connections for VAR-SOM-6UL and VAR-SOM-MX8MM outputs for peripherals on 200-pin SODIMM connector.

Pin No.	TCX SOM interface	TCX signal	Pin No.	TCX SOM interface	TCX signal
1	NC	X	2	GND	GND
3	ETH\_TRX0\_P	ETH\_RX\_P	4	NC	X
5	ETH\_TRX0\_N	ETH\_RX\_N	6	NC	X
7	GND	GND	8	GND	GND
9	ETH\_TRX1\_P	ETH\_TX\_P	10	NC	X
11	ETH\_TRX1\_N	ETH\_TX\_N	12	NC	X
13	GND	GND	14	GND	GND
15	LED\_ACT	ETH\_LED\_YELLOW	16	LED\_LINK10\_100\_1000	ETH\_LED\_GREEN
17	GPIO5\_IO05	1WIRE\_SLPZ	18	GPIO3\_IO24	SOM\_DI5
19	GND	GND	20	GPIO3\_IO25	SOM\_DI4
21	GPIO4\_IO23	TPM\_IRQ	22	GPIO4\_IO22	SOM\_DI3
23	GPIO4\_IO21	FREE\_GPIO4\_IO21	24	GPIO4\_IO24	SOM\_DI2
25	GPIO4\_IO25	FREE\_GPIO4\_IO25	26	GPIO4\_IO26	SOM\_DI1
27	GND	GND	28	GND	GND
29	GPIO1\_IO07	FREE\_GPIO1\_IO07	30	GPIO1\_IO17	FREE\_GPIO1\_IO17
31	NC	X	32	VCC\_SOM	+3V3\_SOM
33	NC	X	34	VCC\_SOM	+3V3\_SOM
35	NC	X	36	VCC\_SOM	+3V3\_SOM
37	GND	GND	38	VDD\_ENET	+3V3\_SOM
39	GPIO5\_IO09	FREE\_GPIO5\_IO09	40	USB1\_OTG\_OC	USB1\_OTG\_FAULT
41	~ECSPI1\_MISO	SPI1\_MISO	42	BOOT\_SEL	BOOT\_SEL\_SOM
43	~ECSPI1\_SCLK	SPI1\_SCLK	44	NC	X
45	~ECSPI1\_MOSI	SPI1\_MOSI	46	NC	X
47	GND	GND	48	GPIO1\_IO02	EEPROM\_#WC\_1
49	SOM\_3V3\_PER	SOM\_PER	50	NC	X
51	NC	X	52	NC	X
53	NC	X	54	UART1\_RXD	SOM\_UART1\_RX
55	NC	X	56	UART1\_TXD	SOM\_UART1\_TX
57	NC	X	58	GND	GND
59	GND	GND	60	SD2\_CLK	SD2\_CLK
61	SD2\_DATA2	SD2\_DATA2	62	SD2\_DATA0	SD2\_DATA0
63	SD2\_DATA1	SD2\_DATA1	64	SD2\_CMD	SD2\_CMD
65	SD2\_DATA3	SD2\_DATA3	66	GND	GND
67	GND	GND	68	PWM2\_OUT	DIO\_PWM2
69	PWM3\_OUT	DIO\_PWM3	70	ECSPI2\_MOSI	SPI2\_MOSI
71	GPIO2\_IO19	RS485\_1\_2\_INT	72	GPIO1\_IO11	HMI\_IRQ
73	GPIO4\_IO27	HUB\_ENABLE	74	GPIO1\_IO16	FREE\_GPIO1\_IO16
75	ECSPI2\_SCLK	SPI2\_SCLK	76	GND	GND
77	ECSPI2\_MISO	SPI2\_MISO	78	GND	GND
79	ECSPI2\_SS0	SPI2\_CS0\_TPM	80	USB1\_OTG\_ID	USB1\_OTG\_ID\_SOM
81	~GPIO1\_IO00	RS485\_INT	82	GPIO5\_IO01	EXP2\_NRST\_SOM
83	UART4\_RXD	SOM\_UART4\_RX	84	GPIO4\_IO03	EXP1\_NRST\_SOM
85	UART4\_TXD	SOM\_UART4\_TX	86	~BOOT\_CFG03	BOOT\_GPIO4\_IO05
87	I2C2\_SDA	I2C2\_SDA	88	I2C2\_SCL	I2C2\_SCL
89	GND	GND	90	~I2C3\_SDA	I2C3\_SDA
91	GPIO1\_IO15	HW\_VER	92	~I2C3\_SCL	I2C3\_SCL
93	GPIO4\_IO10	SPI2\_CS2\_RS485	94	USB1\_ID	USB1\_OTG\_ID\_SOM
95	GND	GND	96	GPIO1\_IO06	UIO\_RST
97	GPIO1\_IO23	FREE\_GPIO1\_IO23	98	PMIC\_PWRON\_B	NRST\_SOM
99	~GPIO1\_IO14	HMI\_DPSW5	100	NC	X
101	GND	GND	102	NC	X
103	VCC\_SOM	+3V3\_SOM	104	USB2\_VBUS	+5V
105	VCC\_SOM	+3V3\_SOM	106	USB1\_VBUS	+5V
107	VCC\_SOM	+3V3\_SOM	108	USB2\_D\_N	USB2\_SOM\_N
109	VCC\_SOM	+3V3\_SOM	110	USB2\_D\_P	USB2\_SOM\_P
111	VCC\_SOM	+3V3\_SOM	112	GND	GND
113	GPIO4\_IO28	HMI\_GPO	114	USB1\_D\_N	USB1\_SOM\_N
115	GPIO5\_IO24	FREE\_GPIO5\_IO24	116	USB1\_D\_P	USB1\_SOM\_P
117	GPIO1\_IO08	GPIO\_EXP\_INT	118	GND	GND
119	NC	X	120	GPIO5\_IO02	SOM\_GLOB\_NRST
121	NC	X	122	USB1\_OTG\_PWR	USB1\_OTG\_PWRSW\_EN
123	NC	X	124	UART3\_TXD	SOM\_UART3\_TX
125	NC	X	126	GND	GND
127	NC	X	128	NC	X
129	NC	X	130	NC	X
131	NC	X	132	GND	GND
133	NC	X	134	NC	X
135	NC	X	136	NC	X
137	NC	X	138	GND	GND
139	GND	GND	140	NC	X
141	~BOOT\_CFG10	BOOT\_GPIO4\_IO14	142	NC	X
143	NC	X	144	GND	GND
145	GPIO4\_IO7	BUZZER	146	GPIO4\_IO18	SPI1\_CS1\_GPO
147	GPIO4\_IO12	SOM\_GSM\_NRST	148	GPIO4\_IO02	UIO\_RST\_EN
149	GND	GND	150	~GPIO1\_IO03	MAIN\_BOARD\_LED
151	~BOOT\_CFG04	BOOT\_GPIO4\_IO6	152	GPIO4\_IO13	ESP32\_WDT\_EN
153	~GPIO\_IO5	SPI2\_CS1\_RS485	154	GPIO1\_IO01	ESP32\_WDI
155	~BOOT\_CFG13	BOOT\_GPIO4\_IO17	156	GPIO4\_IO19	SC\_ENABLE
157	~BOOT\_CFG06	BOOT\_GPIO4\_IO08	158	GND	GND
159	GND	GND	160	DSI\_TX1\_N	DSI\_TX1\_N
161	DSI\_TX0\_N	DSI\_TX0\_N	162	DSI\_TX1\_P	DSI\_TX1\_P
163	DSI\_TX0\_P	DSI\_TX0\_P	164	DSI\_TX2\_N	DSI\_TX2\_N
165	DSI\_TX3\_N	DSI\_TX3\_N	166	DSI\_TX2\_P	DSI\_TX2\_P
167	DSI\_TX3\_P	DSI\_TX3\_P	168	DSI\_CLK\_N	DSI\_CLK\_N
169	GND	GND	170	DSI\_CLK\_P	DSI\_CLK\_P
171	GPIO5\_IO25	FREE\_GPIO5\_IO25	172	GND	GND
173	~BOOT\_CFG11	BOOT\_GPIO4\_IO15	174	I2C4\_SCL	I2C4\_SCL
175	UART3\_RXD	SOM\_UART3\_RX	176	I2C4\_SDA	I2C4\_SDA
177	GPIO4\_IO11	LT8912B\_INT\_SOM	178	GND	GND
179	GND	GND	180	NC	X
181	NC	X	182	NC	X
183	NC	X	184	NC	X
185	GND	GND	186	NC	X
187	GPIO4\_IO04	SOM\_GSM\_PWR\_EN	188	NC	X
189	GPIO4\_IO20	ESP\_CHIP\_PU\_SOM	190	NC	X
191	GPIO4\_IO00	RS485\_NRST\_SOM	192	NC	X
193	GPIO4\_IO01	HDMI\_HPD\_SOM	194	NC	X
195	AGND	GND	196	GPIO3\_IO19	FLASH\_#HOLD
197	GPIO3\_IO20	ESP\_GPIO2\_SOM	198	GPIO3\_IO21	SPI1\_CS0\_FLASH
199	GPIO3\_IO22	ESP\_GPIO0\_SOM	200	GPIO3\_IO23	FLASH\_#WP

### VAR-SOM-6UL Table of connections for VAR-SOM-6UL outputs for peripherals on 200-pin SODIMM connector.

Pin No.	TCX SOM interface	TCX signal	Pin No.	TCX SOM interface	TCX signal
1	GND	GND	2	GND	GND
3	ETH\_RXDP	ETH\_RXDP	4	NC	X
5	ETH\_RXDN	ETH\_RXDN	6	NC	X
7	GND	GND	8	GND	GND
9	ETH\_TXDP	ETH\_TXDP	10	NC	X
11	ETH\_TXDN	ETH\_TXDN	12	NC	X
13	GND	GND	14	GND	GND
15	ETH\_LED\_ACT	ETH\_LED\_ACT	16	ETH\_LED\_LINK	ETH\_LED\_LINK
17	GPIO1\_IO5	WDT WDI	18	GPIO1\_IO15	FLASH\_#WP
19	GND	GND	20	GPIO1\_IO11	FLASH\_#HOLD
21	GPIO4\_IO27	SC\_IDLE/BUSY	22	UART5\_CTS\_B	UART\_P4\_CTS
23	GPIO4\_IO23	SPI1E\_CS2	24	UART1\_CTS\_B	UART\_P4\_CTS
25	GPIO4\_IO26	SPI1E\_CS1	26	GPIO4\_IO28	1WIRE\_SLPZ
27	GND	GND	28	GND	GND
29	GPIO1\_IO10	SPI2U\_CS1\_GPO	30	UART1\_CTS\_B	UART\_P3\_CTS
31	NC	X	32	VCC\_SOM	VCC\_SOM
33	NC	X	34	VCC\_SOM	VCC\_SOM
35	NC	X	36	VCC\_SOM	VCC\_SOM
37	GND	GND	38	NC	X
39	SPI4\_CS0	SPI2U\_CS0\_FLASH	40	NC	X
41	SPI4\_MISO	SPI2U\_MISO	42	BOOT\_SEL	SOM\_BOOT\_SEL
43	SPI4\_SCLK	SPI2U\_SCLK	44	UART3\_CTS\_B	UART\_P6\_CTS
45	SPI4\_MOSI	SPI2U\_MOSI	46	NC	X
47	GND	GND	48	UART3\_RX	UART\_P6\_RX
49	NC	X	50	NC	X
51	NC	X	52	NC	X
53	NC	X	54	UART5\_RX	UART\_P2/4\_RX
55	GPIO1\_IO9	CHIP\_PU\_PR\_ESP	56	UART5	UART\_P2/4\_TX
57	GPIO1\_IO8	ESP\_GPIO0	58	GND	GND
59	GND	GND	60	USDHC1\_CLK	SD\_CLK
61	USDHC1\_DATA2	SD\_DATA2	62	USDHC1\_DATA0	SD\_DATA0
63	USDHC1\_DATA1	SD\_DATA1	64	USDHC1\_CMD	SD\_CMD
65	USDHC1\_DATA3	SD\_DATA3	66	NC	X
67	GND	GND	68	PWM2\_OUT	DIO\_PWM1
69	DIO\_PWM2	DIO\_PWM2	70	SPI2\_MOSI	SPI1E\_MOSI
71	GPIO4\_IO14	!GPIO\_EXP\_INT	72	GPIO5\_IO3	HMI\_IRQ
73	GPIO5\_IO1	HUB\_ENABLE	74	NC	X
75	SPI2\_SCLK	SPI1E\_SCLK	76	GND	GND
77	SPI2\_MISO	SPI1E\_MISO	78	GND	GND
79	SPI2\_CS0	SPI1E\_CS0\_TPM	80	NC	X
81	UART4\_CTS	UART\_P3\_CTS	82	NC	X
83	UART1\_RX	UART\_P1/3\_RX	84	GPIO1\_IO19	EXT\_GPIO1
85	UART1\_TX	UART\_P1/3\_TX	86	GPIO1\_IO18	EXT\_GPIO2
87	I2C1\_SDA	I2C\_SC\_SDA\_SOM	88	I2C1\_SCL	I2C\_SC\_SCL\_SOM
89	GND	GND	90	I2C3\_SDA	I2CS\_SDA
91	BOOT6\_MODE1		92	I2C3\_SCL	I2CS\_SCL
93	BOOT6\_MODE0		94	USB1\_OTG\_ID	USB1\_OTG\_ID
95	GND	GND	96	GPIO3\_IO11	PROG\_EN\_ESP
97	NC	X	98	NC	X
99	NC	X	100	NC	X
101	GND	GND	102	NC	X
103	VCC\_SOM	+3V3\_SOM	104	USB2\_VBUS	USB2\_VBUS
105	VCC\_SOM	+3V3\_SOM	106	USB1\_VBUS	USB1\_VBUS
107	VCC\_SOM	+3V3\_SOM	108	USB2\_D\_N	USB2\_D\_N
109	VCC\_SOM	+3V3\_SOM	110	USB2\_D\_P	USB2\_D\_P
111	VCC\_SOM	+3V3\_SOM	112	GND	GND
113	GPIO4\_IO28	WTD\_REFRESH\_ESP	114	USB1\_D\_N	USB1\_D\_N
115	NC	X	116	USB1\_D\_P	USB1\_D\_P
117	UART8\_CTS\_B	UART\_P5\_CTS	118	GND	GND
119	NC	X	120	GPIO5\_IO5	TPM\_IRQ
121	NC	X	122	USB1\_OTG\_PWR	USB1\_OTG\_PWRCTRL
123	NC	X	124	UART8	UART\_P5\_TX
125	NC	X	126	GND	GND
127	NC	X	128	UART3\_TX	UART\_P6\_TX
129	NC	X	130	NC	X
131	NC	X	132	GND	GND
133	NC	X	134	NC	X
135	NC	X	136	NC	X
137	NC	X	138	GND	GND
139	GND	GND	140	NC	X
141	NC	X	142	NC	X
143	NC	X	144	GND	GND
145	GPIO3\_IO4	EXT\_GPIO3	146	NC	X
147	NC	X	148	NC	X
149	GND	GND	150	NC	X
151	NC	X	152	NC	X
153	NC	X	154	NC	X
155	NC	X	156	NC	X
157	NC	X	158	GND	GND
159	GND	GND	160	DSI\_TX1\_N	DSI\_TX1\_N
161	DSI\_TX0\_N	DSI\_TX0\_N	162	DSI\_TX1\_P	DSI\_TX1\_P
163	DSI\_TX0\_P	DSI\_TX0\_P	164	DSI\_TX2\_N	DSI\_TX2\_N
165	DSI\_TX3\_N	DSI\_TX3\_N	166	DSI\_TX2\_P	DSI\_TX2\_P
167	DSI\_TX3\_P	DSI\_TX3\_P	168	DSI\_CLK\_N	DSI\_CLK\_N
169	GND	GND	170	DSI\_CLK\_P	DSI\_CLK\_P
171	NC	X	172	GND	GND
173	NC	X	174	I2C4\_SCL	I2CE\_SCL
175	UART8\_RX	UART\_P5\_RX	176	I2C4\_SDA	I2CE\_SDA
177	NC	X	178	GND	GND
179	GND	GND	180	NC	X
181	NC	X	182	NC	X
183	NC	X	184	NC	X
185	GND	GND	186	NC	X
187	GPIO1\_IO3	EXT\_GPIO4	188	NC	X
189	USB1\_OTG\_PWR	USB1\_OTG\_PWRCTRL	190	NC	X
191	GPIO1\_IO2	SOM\_GLOBAL\_NRST	192	NC	X
193	GPIO1\_IO1	LT8912B\_INT\_SOM	194	NC	X
195	AGND	AGND	196	GPIO1\_IO12	SOM\_DI1
197	GPIO1\_IO13	SOM\_DI5	198	GPIO1\_IO14	SOM\_DI2
199	GPIO1\_IO12	SOM\_DI4	200	GPIO1\_IO13	SOM\_DI3

# HMI Connectors Signals for the front panel with 1.27 mm connectors raster.

HMI 1 2x9 THT
Pin No.	Signal	Pin No.	Signal
1	ETH\_LED\_YELLOW	10	+5V
2	BOOT\_SEL	11	+3V3
3	GND	12	GND
4	GND	13	HMI\_GPO
5	GND	14	HMI\_DPSW5
6	SIM\_LED\_#WWAN	15	UART\_MUX2\_SEL0
7	GND	16	UART\_MUX1\_SEL0
8	+3V3	17	USB1\_MUX\_SEL0
9	+5V	18	ETH\_LED\_GREEN

HMI 2 2x6 SMD
Pin No.	Signal	Pin No.	Signal
1	I2C3\_SDA	7	GND
2	GND	8	GND
3	+20V	9	HMI\_IRQ
4	NRST\_GLOBAL	10	+20V
5	RESET\_SWITCH	11	GND
6	GND	12	I2C3\_SCL

# Expander Connectors ### EXT Connector SPI, SDIO, USB, I2C, GPIO, reset signal and supply voltages: 1.8 V, 3.3 V, 5 V and 20 V are put out on EXT expander connector.

EXT 2x22 SMD
Pin No.	Signal	Pin No.	Signal
1	GND	23	GND
2	VIN	24	I2C3 SDA
3	GND	25	I2C3 SCL
4	SPI1 MOSI	26	GND
5	GND	27	+3V3
6	SPI1 SCLK	28	GND
7	GND	29	USB3 positive pole
8	SPI1 MISO	30	USB3 negative pole
9	GND	31	GND
10	RTC battery power supply	32	+20V
11	External watchdog reset	33	UIO reset
12	NC	34	NC
13	GND	35	NC
14	NC	36	+1V8
15	NC	37	+1V8
16	NC	38	GND
17	GPIO4 IO25	39	+5V
18	GND	40	+5V
19	GPIO1 IO07	41	GND
20	GPIO4 IO21	42	GND
21	GPIO5 IO09	43	VIN
22	Global reset	44	GND

### Expander E (GPIO, RS485 termination and DIO)

MCP23017-E/ML
Pin No.	Signal	Pin No.	Signal
1	DIO\_DI4	15	GPIO\_EXP\_INT
2	DIO\_DI5	16	GPIO\_EXP\_INT
3	DIO\_DI6	17	TERM\_RS485\_4
4	DIO\_DI7	18	TERM\_RS485\_3
5	+3V3	19	TERM\_RS485\_2
6	GND	20	TERM\_RS485\_1
7	X	21	X
8	I2C3\_SCL	22	X
9	I2C3\_SDA	23	SC\_IDLE/BUSY
10	X	24	DIO\_DI1
11	+3V3	25	DIO\_DI2
12	+3V3	26	SD\_DETECT
13	GND	27	VIN\_LEVEL\_ERR
14	EXP1\_NRST	28	DIO\_DI2

# I2C Devices Addresses

Addresses IMX8
Circuit	PN	Address	Extra
Addresses I2C4
Secure chip	TO136	1010000 (0x50)
ESP32	ESP32-D0WD	XXXXXXX	defined in microcontroller
GSM	SIM7600		I2C through NC resistor
DSI - HDMI bridge	LT8912B	1001000 (0x48, 0x49, 0x4a, 0x4b)
Addresses I2C3
RTC	DS1338	1101000 (0x68)
ADC 1	NAU7802SGI	0101010 (0x2A)
HMI PANEL display	SCE087002-V01	0111100 (0x3C)
HMI PANEL expander	MCP23017	0100001 (0x21)
GPIO expander	MCP23017-E/ML	0100011 (0x23)
Addresses I2C2
EEPROM	M24C02-RMC6	1010110 (0x56)
EEPROM SN	M24C02-RMC6	1010010 (0x52)
Expander C	MCP23017-E/ML	0100000 (0x20)
ADC 2	NAU7802SGI	0101010 (0x2A)
DAC	DAC7574IDGSR	1001100 (0x4C)
1-Wire bridge	DS2484	0011000 (0x18)
Addresses Virtual I2C
HDMI Connector I2C	206H-SDAN-R01	1010000, 0110111 (0x50, 0x37)