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Reset State of the i.MX 8/8X SoC Pins

 

Article updated at 20 Apr 2021
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Introduction

Note: currently, we only provide information about Apalis iMX8, based on NXP i.MX 8. Soon we will add information about Apalis iMX8X and Colibri iMX8X. If you need this with urgency, please contact our support.

The pin configuration registers of the i.MX 8 SoC has reset states. These reset states have been stated in the Toradex Apalis iMX8 datasheet (document revision 1.1 and earlier) as reset states in section 4.4.

However, the i.MX 8 SoC features a system control unit (SCU) that handles all the pin configuration. The SCU comes with a firmware (SCUFW) that has its own default configuration. During the release of the RESET_MOCI# signal, the SCU has already reconfigured the IOs. Therefore, the default settings of the SCU are the relevant reset states for the pins. These reset values can be found in the i.MX 8 datasheet provided by NXP. For some pins, the SCUFW reset state is different from the register reset states. The Toradex Apalis iMX8 datasheet (document revision 1.2 and newer) has been updated to these values.

This document compares the reset state previously stated in the Toradex Apalis iMX8 datasheet (register reset state) with the relevant SCUFW reset state.

Prerequisites

The following Toradex SoMs features i.MX 8QM SoC:

Reset state

Reset state comparison

Abbreviations:

PD: Push-down

X1 Pin i.MX 8 Ball Name Apalis Signal Name Reset State (Register) Reset State (SCFW)
1 M40_GPIO0_00 GPIO1 PD PD
3 M40_GPIO0_01 GPIO2 PD PD
5 M41_GPIO0_00 GPIO3 PD PD
7 M41_GPIO0_01 GPIO4 PD PD
11 FLEXCAN2_RX GPIO5 PD PD
13 FLEXCAN2_TX GPIO6 Drive-1 PD
15 MLB_SIG GPIO7 PD PD
17 MLB_DATA GPIO8 PD PD
35 ESAI1_TX0 SATA1_ACT# PD PD
37 SPI3_CS0 WAKE1_MICO PD PD
63 MLB_CLK TS_1 PD PD
87 LVDS0_I2C0_SCL TS_2 PD PU
99 LVDS0_I2C0_SDA TS_3 PD PU
123 MIPI_DSI1_GPIO0_00 TS_4 PD PD
135 SIM0_IO TS_5 Drive-0 PD
159 USDHC1_STROBE TS_6 PD PU
173 MIPI_DSI1_I2C0_SCL CAM1_D7 PD PU
175 MIPI_DSI1_I2C0_SDA CAM1_D6 PD PU
177 ESAI0_TX0 CAM1_D5 PD PD
179 ESAI0_TX1 CAM1_D4 PD PD
181 ESAI0_TX2_RX3 CAM1_D3 PD PD
183 ESAI0_TX3_RX2 CAM1_D2 PD PD
185 ESAI0_TX4_RX1 CAM1_D1 PD PD
187 ESAI0_TX5_RX0 CAM1_D0 PD PD
191 MCLK_IN0 CAM1_PCLK PD PD
193 SPI3_SDO CAM1_MCLK Drive-1 PD
195 ESAI0_SCKR CAM1_VSYNC PD PD
197 ESAI0_SCKT CAM1_HSYNC PD PD
201 SIM0_POWER_EN I2C3_SDA (CAM) Drive-0 PD
203 SIM0_PD I2C3_SCL (CAM) PD PD
209 GPT1_CAPTURE I2C1_SDA PD PD
211 GPT1_CLK I2C1_SCL PD PD
215 SPDIF0_TX SPDIF1_OUT Drive-0 PD
217 SPDIF0_RX SPDIF1_IN PD PD
221 SPI0_SCK SPI1_CLK PD PD
223 SPI0_SDI SPI1_MISO PD PD
225 SPI0_SDO SPI1_MOSI Drive-1 PD
227 SPI0_CS0 SPI1_CS PD PD
229 SPI2_SDI SPI2_MISO PD PD
231 SPI2_SDO SPI2_MOSI Drive-1 PD
233 SPI2_CS0 SPI2_CS PD PD
235 SPI2_SCK SPI2_CLK PD PD
239 LVDS1_GPIO00 BKL1_PWM PD PD
243 ENET1_RGMII_RXD3 LCD1_PCLK PD PD
245 ENET1_RGMII_RXD2 LCD1_VSYNC PD PD
247 ENET1_RGMII_RXD1 LCD1_HSYNC PD PD
249 ENET1_RGMII_RXD0 LCD1_DE PD PD
251 ENET1_MDIO LCD1_R0 PD PU
253 ENET1_MDC LCD1_R1 Drive-0 PD
255 ENET1_RGMII_TXD2 LCD1_R2 Drive-0 PD
257 ENET1_RGMII_TXD1 LCD1_R3 Drive-0 PD
259 ENET1_RGMII_TXD0 LCD1_R4 Drive-0 PD
261 ENET1_RGMII_TXC LCD1_R5 Drive-0 PD
263 ENET1_RGMII_TX_CTL LCD1_R6 Drive-0 PD
265 ENET1_RGMII_RX_CTL LCD1_R7 PD PD
269 ENET1_REFCLK_125M_25M LCD1_G0 Drive-0 PD
271 ESAI0_FSR LCD1_G1 PD PD
273 ESAI0_FST LCD1_G2 PD PD
275 SIM0_GPIO0_00 LCD1_G3 Drive-0 PD
277 SIM0_RST LCD1_G4 Drive-0 PD
279 SIM0_CLK LCD1_G5 Drive-0 PD
281 LVDS1_I2C0_SCL LCD1_G6 PD PU
283 LVDS1_I2C0_SDA LCD1_G7 PD PU
287 QSPI1A_DATA0 LCD1_B0 PD PD
289 QSPI1A_DATA1 LCD1_B1 PD PD
291 QSPI1A_DATA2 LCD1_B2 PD PD
293 QSPI1A_DATA3 LCD1_B3 PD PD
295 QSPI1A_SS0_B LCD1_B4 PD PU
297 QSPI1A_DQS LCD1_B5 PD PD
299 QSPI1A_SS1_B LCD1_B6 PD PU
301 QSPI1A_SCLK LCD1_B7 PD PD
305 ADC_IN0 AN1_ADC0 PD PD
307 ADC_IN1 AN1_ADC1 PD PD
309 ADC_IN2 AN1_ADC2 PD PD
311 ADC_IN3 AN1_TSWIP_ADC3 PD PD
315 ADC_IN4 AN1_TSPX PD PD
317 ADC_IN5 AN1_TSMX PD PD
319 ADC_IN6 AN1_TSPY PD PD
321 ADC_IN7 AN1_TSMY PD PD
2 GPT1_COMPARE PWM1 PD PD
4 GPT0_COMPARE PWM2 PD PD
6 UART0_RTS_B PWM3 Drive-1 PD
8 UART0_CTS_B PWM4 PD PD
12 FLEXCAN0_RX CAN1_RX PD PD
14 FLEXCAN0_TX CAN1_TX Drive-1 PD
16 FLEXCAN1_RX CAN2_RX PD PD
18 FLEXCAN1_TX CAN2_TX Drive-1 PD
84 USB_SS3_TC1 USBH_EN PD PU
96 USB_SS3_TC3 USBH_OC# PD PU
110 M40_I2C0_SCL UART1_DTR PD PU
112 UART1_TX UART1_TXD Drive-1 PD
114 UART1_RTS_B UART1_RTS Drive-1 PD
116 UART1_CTS_B UART1_CTS PD PD
118 UART1_RX UART1_RXD PD PD
120 M40_I2C0_SDA UART1_DSR PD PU
122 M41_I2C0_SDA UART1_RI PD PU
124 M41_I2C0_SCL UART1_DCD PD PU
126 LVDS1_I2C1_SCL UART2_TXD PD PU
128 ENET1_RGMII_TXD3 UART2_RTS Drive-0 PD
130 ENET1_RGMII_RXC UART2_CTS PD PD
132 LVDS1_I2C1_SDA UART2_RXD PD PU
134 UART0_TX UART3_TXD Drive-1 PD
136 UART0_RX UART3_RXD PD PD
138 LVDS0_I2C1_SCL UART4_TXD PD PU
140 LVDS0_I2C1_SDA UART4_RXD PD PU
144 USDHC1_DATA2 MMC1_D2 PD PU
146 USDHC1_DATA3 MMC1_D3 PD PU
148 USDHC1_DATA4 MMC1_D4 PD PU
150 USDHC1_CMD MMC1_CMD PD PD
152 USDHC1_DATA5 MMC1_D5 PD PU
154 USDHC1_CLK MMC1_CLK Drive-0 Drive-0
156 USDHC1_DATA6 MMC1_D6 PD PU
158 USDHC1_DATA7 MMC1_D7 PD PU
160 USDHC1_DATA0 MMC1_D0 PD PU
162 USDHC1_DATA1 MMC1_D1 PD PU
164 ESAI1_TX1 MMC1_CD# PD PD
176 USDHC2_DATA2 SD1_D2 PD PU
178 USDHC2_DATA3 SD1_D3 PD PU
180 USDHC2_CMD SD1_CMD PD PD
184 USDHC2_CLK SD1_CLK Drive-0 PD
186 USDHC2_DATA0 SD1_D0 PD PU
188 USDHC2_DATA1 SD1_D1 PD PU
190 USDHC2_CD_B SD1_CD# PD PU
194 SPI3_SDI DAP1_MCLK PD PD
196 SAI1_RXC DAP1_D_OUT PD PD
198 ESAI1_SCKT DAP1_RESET PD PD
200 SPI0_CS1 DAP1_BIT_CLK PD PD
202 SAI1_RXFS DAP1_D_IN PD PD
204 SPI2_CS1 DAP1_SYNC PD PD
262 USB_SS3_TC2 USBO1_OC# PD PU
274 USB_SS3_TC0 USBO1_EN PD PU
286 LVDS0_GPIO00 BKL1_ON PD PD

Impacts on Toradex Carrier Boards

Four pins could have the following impact with the Toradex carrier boards:

Pin Difference Effect
USBO1_EN pulled-up instead of pulled-down The USB power gets enabled during reset
USBH_EN pulled-up instead of pulled-down Depending on the carrier board, the USB power gets enabled during the reset
MMC1_D5 pulled-up instead of pulled-down On Ixora, this pin is used for driving an LED (LED5_GREEN). This LED could be lit during the reset state
MMC1_D6 pulled-up instead of pulled-down On Ixora, this pin is used for driving an LED (LED5_RED). This LED could be lit during the reset state