SPRUJ66B February 2023 – September 2025
The boot mode for the SK EVM board is defined by two banks of switches SW2 and SW3 or by the I2C buffer connected to the Test automation connector. This allows for AM62A SOC Boot mode control by either the user (DIP Switch Control) or by the Test Automation connector.
All the bits of switch (SW2 and SW3) have weak pull down resistor and a strong pull up resistor as shown in Figure 2-31. Note that OFF setting provides a low logic level (‘0’) and an ON setting provide a high logic level (‘1’).
Figure 2-31 Bootmode SwitchesThe boot mode pins of the SOC have associated alternate functions during normal operation. Hence, isolation is provided using Buffer IC’s to cater for alternate pin functionality. The output of the buffer is connected to the boot mode pins on the AM62A SOC and the output is enabled only when the boot mode is needed during a reset cycle.
The input to the buffer is connected to the DIP switch circuit and to the output of an I2C IO Expander set by the test automation circuit. If the test automation circuit controls the boot mode, all the switches can be manually set to the OFF position. The boot mode buffer is powered by an always ON power supply to make sure that the boot mode remains present even if the SOC is power cycled.
Switch SW2 and SW3 bits [15:0] are used to set the SOC Boot mode.
The switch map to the boot mode functions is provided in the tables below.
| Bit15 | Bit14 | Bit13 | Bit12 | Bit11 | Bit10 | Bit9 | Bit8 | Bit7 | Bit6 | Bit5 | Bit4 | Bit3 | Bit2 | Bit1 | Bit0 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Reserved | Reserved | Backup Boot Mode Configuration | Backup Boot Mode | Primary Boot Mode Configuration | Primary Boot Mode | PLL Configuration | |||||||||
| SW2.3 | SW2.2 | SW2.1 | PLL REF CLK (MHz) |
|---|---|---|---|
| OFF | OFF | OFF | 19.2 |
| OFF | OFF | ON | 20 |
| OFF | ON | OFF | 24 |
| OFF | ON | ON | 25 |
| ON | OFF | OFF | 26 |
| ON | OFF | ON | 27 |
| ON | ON | OFF | RSVD |
| ON | ON | ON | RSVD |
| SW2.7 | SW2.6 | SW2.5 | SW2.4 | Primary Boot Device Selected |
|---|---|---|---|---|
| OFF | OFF | OFF | OFF | Serial NAND |
| OFF | OFF | OFF | ON | OSPI |
| OFF | OFF | ON | OFF | QSPI |
| OFF | OFF | ON | ON | SPI |
| OFF | ON | OFF | OFF | Ethernet RGMII |
| OFF | ON | OFF | ON | Ethernet RMII |
| OFF | ON | ON | OFF | I2C |
| OFF | ON | ON | ON | UART |
| ON | OFF | OFF | OFF | MMC/SD card |
| ON | OFF | OFF | ON | eMMC |
| ON | OFF | ON | OFF | USB0 |
| ON | OFF | ON | ON | GPMC NAND |
| ON | ON | OFF | OFF | GPMC NOR |
| ON | ON | OFF | ON | Rsvd |
| ON | ON | ON | OFF | xSPI |
| ON | ON | ON | ON | No boot/Dev Boot |
| SW3.2 | SW3.1 | SW2.8 | Boot Device |
|---|---|---|---|
| Reserved | Read Mode 2 | Read Mode 1 | Serial NAND |
| Reserved | Iclk | Csel | QSPI |
| Reserved | Iclk | Csel | OSPI |
| Reserved | Mode | Csel | SPI |
| Clkout | 0 | Link Info | Ethernet RGMII |
| Clkout | Clk src | 0 | Ethernet RMII |
| Bus Reset | Reserved | Addr | I2C |
| Reserved | Reserved | Reserved | UART |
| 1 | Reserved | Fs/raw | MMC/ SD card |
| Reserved | Reserved | Reserved | eMMC |
| Core Volt | Mode | Lane swap | USB0 |
| Reserved | Reserved | Reserved | GPMC NAND |
| Reserved | Reserved | Reserved | GPMC NOR |
| Reserved | Reserved | Reserved | Reserved |
| SFPD | Read Cmd | Mode | xSPI |
| Reserved | ARM/Thumb | No/Dev | No boot/Dev Boot |
| BOOTMODE Pins | Field | Value | Description |
|---|---|---|---|
| 8 [SW3.1] | Read Mode 2 | 0 | Reserved (Read mode is taken from Read Mode 1 |
| 1 |
SPI/ 1-1-1 mode (Read mode is taken from Read Mode 2 and Read Mode 1 is ignored) |
||
| 7 [SW2.8] | Read Mode 1 | 0 | OSPI/ 1-1-8 Mode (valid only when Read Mode 2 is 0) |
| 1 | OSPI/ 1-1-4 Mode (valid only when Read Mode 2 is 0) |
| BOOTMODE Pins | Field | Value | Description |
|---|---|---|---|
| 7 [SW2.8] | Csel | 0 | Boot Flash is on CS 0 |
| 1 | Boot Flash is on CS 1 |
| BOOTMODE Pins | Field | Value | Description |
|---|---|---|---|
| 7 [SW2.8] | Csel | 0 | Boot Flash is on CS 0 |
| 1 | Boot Flash is on CS 1 |
| BOOTMODE Pins | Field | Value | Description |
|---|---|---|---|
| 8 [SW3.1] | Mode | 0 | SPI Mode 0 |
| 1 | SPI Mode 3 | ||
| 7 [SW2.8] | Csel | 0 | Boot Flash is on CS 0 |
| 1 | Boot Flash is on CS 1 |
| BOOTMODE Pins | Field | Value | Description |
|---|---|---|---|
| 9 [SW3.2] | Clkout | 0 | Must be set to 0 to choose external clock |
| 1 | Reserved | ||
|
8 [SW3.1] |
Delay | 0 | Must be set to 0 for RGMII with internal Tx delay |
| 1 | Reserved | ||
| 7 [SW2.8] | Link info | 0 | MDIO PHY scan used for link parameters |
| 1 | Link parameters programmed by the ROM |
| BOOTMODE Pins | Field | Value | Description |
|---|---|---|---|
| 9 [SW3.2] | Clkout | 0 | 50MHz clock not generated on CLKOUT0 |
| 1 | 50MHz clock generated on CLKOUT0 | ||
|
8 [SW3.1] |
Clk src | 0 | External clock source for RMII1_REF_CLK |
| 1 | Internal clock source for RMII1_REF_CLK | ||
| 7 [SW2.8] | RMII | 0 | This bit must be set to 0 |
| 1 | Reserved |
| BOOTMODE Pin 9 (Clk out) | BOOTMODE Pin 8 (Clk src) | Description |
|---|---|---|
| 0 | 0 |
50MHz external source to RMII_REF_CLK and to external Ethernet PHY input clock (CLKOUT0 is unused) These are the recommended settings |
| 0 | 1 | Not a valid configuration |
| 1 | 0 |
CLKOUT0 is configured to 50MHz and connect to both RMII1_REF_CLK and to external Ethernet PHY input clock |
| 1 | 1 | Not a valid configuration |
| BOOTMODE Pins | Field | Value | Description |
|---|---|---|---|
| 13 [SW3.2] | Interface | 0 | RGMII with internal TX delay |
| 1 | RMII with external clock source |
| BOOTMODE Pins | Field | Value | Description |
|---|---|---|---|
| 9 [SW3.2] | Bus reset | 0 | Hung bus reset attempt after 1ms |
| 1 | No hung bus reset attempted | ||
| 7 [SW2.8] | Address | 0 | EEPROM's address is 0x50 |
| 1 | EEPROM's address is 0x51 |
| BOOTMODE Pins | Field | Value | Description |
|---|---|---|---|
|
9 [SW3.2] 13(1) [SW3.2] |
Port | 0 | Reserved |
| 1 | MMC Port 1 (4 bit width). This bit must be set to 1 | ||
| 7 [SW2.8] | FS/Raw | 0 | File system mode |
| 1 | Raw Mode |
| BOOTMODE Pins | Field | Value | Description |
|---|---|---|---|
|
9 [SW3.2] 13(1) [SW3.2] |
Port | 0 | MMCSD Port 0 (8 bit width). This bit must be set to 0 |
| 1 | Reserved | ||
| 7 [SW2.8] | FS/Raw | 0 | Filesystem mode |
| 1 | Raw Mode |
| BOOTMODE Pins | Field | Value | Description |
|---|---|---|---|
| 9 [SW3.2] | Core Voltage | 0 | 0.85V core voltage |
| 1 | 0.75V core voltage | ||
|
8 [SW3.1] 13(1) [SW3.2] |
Mode | 0 | DFU (USB device firmware upgrade) |
| 1 | Host (MSC boot) | ||
| 7 [SW2.8] | Lane Swap | 0 | D+/D- lines are not swapped |
| 1 | D+/D- lines are swapped |
| BOOTMODE Pins | Field | Value | Description |
|---|---|---|---|
| 9 [SW3.2] | SFDP | 0 | SFDP disabled |
| 1 | SFDP enabled | ||
|
8 [SW3.1] |
Read cmd | 0 | 0x0B Read Command |
| 1 | 0xEE Read Command | ||
| 7 [SW2.8] | Mode | 0 | 1S-1S-1S mode @ 50MHz |
| 1 | 8D-8D-8D mode @ 25MHz |
| SW3.5 | SW3.4 | SW3.3 | Backup Boot Device Selected |
|---|---|---|---|
| OFF | OFF | OFF | None(No backup mode) |
| OFF | OFF | ON | USB |
| OFF | ON | OFF | Reserved |
| OFF | ON | ON | UART |
| ON | OFF | OFF | Ethernet |
| ON | OFF | ON | MMC/SD |
| ON | ON | OFF | SPI |
| ON | ON | ON | I2C |