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AM37x To AM335x Hardware Migration Guide
Content is no longer maintained and is being kept for reference only!
- 1 Introduction
- 2 Software Migration Guide
- 3 Basic Feature comparison
- 4 Module Comparison
- 4.1 Processors
- 4.2 External Memory Interfaces
- 4.3 Power, Reset, and Clock Management
- 4.4 Multimedia Hardware Components
- 4.5 Communication Interfaces
- 4.6 Timers
- 4.7 Misc
- 4.8 New interfaces in AM335x
- 4.9 Pin and package
This article documents the differences between the TI AM37x and the TI AM335x processors. Note that AM37x is the ARM-only version of DM3730 processor. All of the documentation referenced in this migration guide can be found on the TI website located in the two device respective product folders. The device folders are found at the following web pages.
The device folders are found at the following web pages:
Software Migration Guide
For more information on software migration, please see:
Basic Feature comparison
The table below shows a comparison of the basic features of the AM37x and the AM335x. The remainder of this document presents a comparison of these features in greater detail, and also provides references to the appropriate documentation for further information.
|Device Family||AM3703 - CortexA8
AM3715 - CortexA8 with SGX 530
|AM3357/6/2 - CortexA8 |
AM3359/8/4 - CortexA8 with SGX 530
|Packages||515-pin s-PBGA (CBP), .5-mm Ball Pitch (top), .4-mm Ball Pitch(bottom)
515-pin s-PBGA (CBC), .65-mm Ball Pitch (top), .5-mm Ball Pitch (bottom)
423-pin s-PBGA (CUS), .65-mm Ball Pitch, layout using .80-mm rules
|284-pin nFBGA (ZCE), .65-mm Ball Pitch with VCA|
324-Pin nFBGA (ZCZ), .80-mm Ball Pitch Full Array
|Co-processors and Subsystems|
|ARM Processor||Cortex-A8 up to 1GHz;
32K-Byte Instruction and Data Caches;
256K-Byte L2 Cache
|Cortex-A8 up to 720MHz; |
32K-Byte Instruction and Data Caches;
256K-Byte L2 Cache w/ECC
|Supported OPP: 50/100/130/1G||Supported OPP: 50/100/120/SRTurbo|
|Trustzone: Supported||Trustzone: Not supported|
|SGX530 3D Graphics Engine||Y||Y|
16, 32-bit memory controller with 1G-Byte total address space
16-bit memory controller with 1G-Byte total address space
|General Purpose Memory Controller (GPMC)||1 GB total address space||1 GB total address space|
|POP||CBP & CBC Package||N|
|Discrete memory Interface (non PoP)||CUS Package only||ZCE; ZCZ Package|
|Crypto hardware accelerators||Y||Y|
|Display||Display SubSystem (DSS)||LCD Controller|
|USB Host||3||not present|
|eMAC||not present||10/100/1000 Mbps|
|UART||4 (1 with IrDA)||6 (6 with IrDA)|
|GPIO||6 banks||4 banks|
|ADC/TS||not present||8ch 12bit|
|Power, Reset, and Clock Management|
|ETM & ETB||Y||Y|
|IEEE support||IEEE 1149.1||IEEE 1500|
|32-kHz Sync Timer||1||not present|
AM37x and AM335x are both based on the ARM Cortex-A8 processor. The table below shows a comparison between these two devices.
|ARM Processor||ARM Cortex™ A8||ARM Cortex™ A8|
|Operating Performance Points||OPP50, OPP100, OPP130, OPP1G*||OPP50, OPP100, OPP120, SRTurbo|
|Operating Voltages||.97V, 1.14V, 1.27V, 1.33V*||.95V, 1.1V, 1.2V, 1.26V|
|Operating Frequencies||300MHz, 600MHz, 800MHz, 1000MHz||275MHz, 500MHz, 600MHz, 720MHz|
|L1 Instruction Cache||32 Kbytes||32 Kbytes|
|L1 Data Cache||32 Kbytes||32 Kbytes|
|L1 with SED||No||Yes|
|L2 Cache||256 Kbytes||256 Kbytes|
|L2 with ECC||No||Yes|
|ROM Size||96 Kbytes (64 KB Secure ROM and 32 KB of Boot ROM)||176 Kbytes (128 KB Secure ROM and 48 KB of Public ROM)|
|RAM Size||64 Kbytes (62Kbytes Secure RAM and 2Kbytes Public RAM)||64 Kbytes (Secure/ Public RAM)|
* OPP 1G available with SmartReflex enabled.
Note: Please refer to the AM37x and AM335x Datasheets for the latest OPP values.
The Neon Coprocessor is the same between the two devices.
AM335x integrates an ARM Cortex M3 core that manages entry and exit of various stand-by and deep-sleep modes.
AM37x does not contain a dedicated wake-up controller.
The Graphics Engine SGX530 is binary compatible between the two devices.
AM37x has 64KB RAM.
AM335x has 64KB RAM
External Memory Interfaces
General Purpose Memory Controller
The GPMC module is binary compatible between the two devices. The only difference is the ECC hardware mechanism, which is outside of the GPMC module.
AM37x supports 1-bit (Hamming) and 4-bit, 8-bit (BCH) hardware ECC.
AM335x supports 1-bit (Hamming) ECC and has a new Error Locator Module (ELM) to support 4-bit, 8-bit, or 16-bit (BCH) ECC.
SDRAM Memory Controller
The SDRAM Memory Controller is different between the two devices.
AM37x supports the SDRC Subsystem, providing a 16- or 32-bit interface to m-SDR and LPDDR. 32-bit LPDDR is only supported up to 200MHz clock frequency. The SDRC Sybsystem includes a SDRAM memory scheduler (SMS) and a virtual rotated frame-buffer (VRFB) within the subsystem supports rotations of 0/90/180/270 degrees.
AM335x supports the EMIF, providing a 16-bit interface to mDDR (LPDDR1), DDR2, and DDR3 memories. The EMIF does not support Virtual Rotated Frame Buffer (VRFB) 0/90/180/270 degree rotation in hardware. The AM335x EMIF supports:
- mDDR: up to 200 MHz clock (400 MHz data rate),
- DDR2: up to 266 MHz clock (532 MHz data rate),
- DDR3: up to 303 MHz clock (606 MHz data rate)
Power, Reset, and Clock Management
Operating Performance Points
* OPP 1G available with SmartReflex enabled.
Note: Please refer to the AM37x Datasheet for the latest OPP values.
Note: Please refer to the AM335x Datasheet for the latest OPP values.
The following tables compare the power supplies for AM37x and AM335x:
|vdd_mpu_iva||MPU||0.97V - 1.33V *|
|vdd_core||Core||0.97V - 1.33V *|
|vdds_mmc1||MMC1 dual voltage I/Os||1.8V / 3.0V|
|vdds_x||x dual voltage I/Os||1.8V / 3.0V|
|vdda_dplls_dll||MPU, core DPLLs and DLL||1.8V|
|vssa_dac||Ground for video buffers and DAC||0V|
* Note: Please refer to the AM37x Datasheet for the latest values.
|VDD_MPU *||MPU domain||0.95V - 1.26V|
|CAP_VDD_RTC||RTC domain input/LDO output||1.1V|
|VDDS_DDR||DDR IO domain (DDR2 / DDR3)||1.8V / 1.5V|
|VDDS||Dual voltage IO domains||1.8V|
|VDDS_SRAM_CORE_BG||Core SRAM LDOs, Analog||1.8V|
|VDDS_SRAM_MPU_BB||MPU SRAM LDOs, Analog||1.8V|
|VDDS_PLL_DDR||DPLL DDR, Analog||1.8V|
|VDDS_PLL_CORE_LCD||DPLL Core and LCD, Analog||1.8V|
|VDDS_PLL_MPU||DPLL MPU, Analog||1.8V|
|VDDS_OSC||System oscillator IOs, Analog||1.8V|
|VDDA1P8V_USB0||USB PHY, Analog, 1.8V||1.8V|
|VDDA1P8V_USB1||USB PHY, Analog, 1.8V||1.8V|
|VDDA3P3V_USB0||USB PHY, Analog, 3.3V||3.3V|
|VDDA3P3V_USB1||USB PHY, Analog, 3.3V||3.3V|
|VDDSHV1||Dual Voltage IO domain (1.8-V operation)||1.8V|
|VDDSHV2 *||Dual Voltage IO domain (1.8-V operation)||1.8V|
|VDDSHV3 *||Dual Voltage IO domain (1.8-V operation)||1.8V|
|VDDSHV4||Dual Voltage IO domain (1.8-V operation)||1.8V|
|VDDSHV5||Dual Voltage IO domain (1.8-V operation)||1.8V|
|VDDSHV6||Dual Voltage IO domain (1.8-V operation)||1.8V|
|VDDSHV1||Dual Voltage IO domain (3.3-V operation)||3.3V|
|VDDSHV2 *||Dual Voltage IO domain (3.3-V operation)||3.3V|
|VDDSHV3 *||Dual Voltage IO domain (3.3-V operation)||3.3V|
|VDDSHV4||Dual Voltage IO domain (3.3-V operation)||3.3V|
|VDDSHV5||Dual Voltage IO domain (3.3-V operation)||3.3V|
|VDDSHV6||Dual Voltage IO domain (3.3-V operation)||3.3V|
|DDR_VREF||DDR SSTL/HSTL reference input (DDR2/DDR3)||0.50*VDDS_DDR|
|USB0_VBUS||USB VBUS comparator input|
|USB1_VBUS||USB VBUS comparator input|
|USB0_ID||USB ID input||1.8V|
|USB1_ID||USB ID input||1.8V|
* Note: These voltage rails are not available in the 13x13 package.
Clocks and PLLs
|sys_xtalin/out||High Frequency Input Clock||12, 13, 16.8, 19.2, 26, 38.4 MHz|
|sys_altclk||Alternative Input Clock||48 MHz or 54 MHz|
|sys_32K||Low Frequency Input Clock||32 KHz|
|CLK_M_OSC||Master Oscillator||19.2, 24, 25, 26 MHz|
|CLK_32KHZ||Divide down of PER PLL output (PLL uses Master Osc)||32768 Hz Precise|
|CLK_RC_32KHZ||Internal RC Oscillator||16 - 60 kHz|
|CLK_32K_RTC||External 32768 Hz crystal with internal 32K Osc or external 32768 Hz clock||32768 Hz Precise|
On AM37x, the high frequency clock, alternative input clock, and 32KHz clock were required to be sourced externally. The AM335x has the option to obtain the 32KHz clock from the high frequency 20MHz clock using an internal RTCDIVDER. If this is used, an external 32KHz clock source is not necessary. The 32KHz provides a clock for the following modules:
AM37x has the following PLLs, all driven by the HF clock:
- DPLL1 - MPU
- DPLL3 - Core
- DPLL4 - Peripherals
- DPLL5 - Peripherals 2
AM335x has the following PLLs, driven by a crystal (CLK_M_OSC):
- Core PLL - for SGX, EMAC, L3S, L3F, L4F, L4_PER, L4_WKUP, PRUSS IEP, Debugss
- Peripheral (Per) PLL - for USB PHY, PRUSS UART, MMC/SD, SPI, I2C, UART
- MPU PLL - for MPU Subsystem (includes Cortex A-8)
- Display PLL - for LCD Pixel Clock
- DDR PLL - for EMIF
Power Management Feature Comparison
|HW Provisions for Power Optimization/ Control||AM37x||AM335x|
|Operating Voltage-Frequencies (OPPs)
||OPP50, OPP100, OPP130, OPP1G
||OPP50, OPP100, OPP120, SRTurbo |
|Adaptive Voltage Scaling
||Class 3 Smart Reflex,
VDD1_MPU and VDD2_CORE
|Class 2B Smart Reflex,|
VDD_CORE & VDD_MPU can be scaled. VDD_RTC is Fixed.
|SRAM memory retention
|Logic State Retention
|Individually Switchable Power Domains
||No support for individually ON/OFF of Power Domains
||Full support for individually ON/OFF of Power Domains. Note, in RTC_Only mode even WAKEUP Domain can be OFF|
|Dynamically gating OFF of Clocks to one/more of groups of
modules (clock domains) when inactive to conserve power
|HW Auto Clock/Power Domain Dependency Management
|Low Power Deep-Sleep State w/ Auto Wakeup
||GPIO0 bank, UART0, RTC, I2C0, DMTimer 1ms, USB Resume and TSC/ ADC Control events |
|RTC Only Cold State
||Supported. System includes 32KHz Osc integrated with alarm/wake signaling interface w/ PMIC.|
|Splitting Of Primary Voltage Supply Rails
||VDD_CORE, VDD_MPU*, VDD_RTC|
- * On 13x13 mm package option, VDD_CORE and VDD_MPU are merged.
The available bootmodes for AM37x and AM335x are shown in the table below.
|Y||Y||NOR||This mode allows booting from XIP booting devices, such as NOR flash memories. |
For AM37x, NOR Flash (up to 2 Gb, or 256M bytes) should be connected to the GPMC peripheral on GPMC_nCS0. GPMC_nCS0 is mapped to address 0x0800_0000. A data bus width of x16 is supported. The GPMC is clocked at 48MHz.
For AM355x, NOR Flash (up to 1 Gb, or 128M bytes) should be connected to the GPMC peripheral on GPMC_CSn0. GPMC_CSn0 is mapped to address 0x8000_0000. A data bus width of x8 or x16 is supported. The GPMC is clocked at 50MHz.
This mode starts downloading code from an NAND memory.
For AM335x, NAND flash (from 512Mbit, or 64Mbytes)should be connected to the GPMC peripheral on GPMC_CSn0. GPMC_CSn0 is mapped to address 0x8000_0000. A data bus width of x16 is supported. The GPMC is clocked at 50MHz.
|N||Y||SPI||This mode starts downloading code from an SPI EEPROM or SPI Flash. |
For AM335x, the external SPI device should be connected to the SPI0 chip select 0 signal (SPI0_CS0). SPI EEPROM devices must use 24-bit addressing, and its read command must equal 0x03.
|Y||Y||UART||In this mode, the UART sends a BOOTME request to the UART peripheral and waits for a response along with code from a host processor. |
Both AM37x and AM335x must be booted using a baud rate of 115200. AM37x can only boot from UART3. AM335x can only boot from UART0.
|Y||Y||MMCSD||This mode starts booting code from an MMC/SD Controller. |
For AM37x, the MMC/SD cards should connected to either MMC1 or MMC2. 1.8V or 3.3V I/O voltage is supported on MMC1, and only 1.8V I/O voltage is supported on MMCC2. (External transceiver mode on MMC2 is not supported.) The supported clock frequencies are up to 400 kHz (identification mode) and 20 MHz (data transfer mode).
For AM335x, the MMC/SD cards should connected to either MMC0 or MMC1. 1.8V or 3.3V I/O voltage is supported on MMC0, and only 1.8V I/O voltage is supported on MMC1. The supported clock frequencies are up to 400 kHz (identification mode) and 10 MHz (data transfer mode).
|N||Y||EMAC||This mode starts booting code from the EMAC port. |
For AM335x, EMAC boot uses the CPGMAC port 1 of the device.
|Y||N||DiskOnChip||In this mode, the DiskOnChip is connected just like a regular NOR device.|
|Y||N||HS USB||In this mode, the ROM code boots from a USB interface.|
Multimedia Hardware Components
AM37x has a display subsystem (DSS) that supports the following resolutions: XGA, WXGA, SXGA+, and HD 720p.
AM335x has a simple LCD controller with no preprocessing operations such as preview, overlay, blending, resizing, etc. The AM335x LCD controller supports up to WXGA resolution.
A camera subsystem is not supported on AM335x.
The AM37x and AM335x devices support different versions of industry standards (shown below).
|Spec Compliance||MMC v4.2 *
SD card v2.0
SD card v2.0
|Data width **||8-bit (MMC2/3)
|Max Clock Rate||48MHz (MCC),
* Note full compliance with the MMC command/response sets and MMC bus testing procedure, as defined in the Multimedia Card System Specification, v4.2, does not prevent the use of e.MMC version 4.3 (or 4.4) devices with the AM37x, because e.MMC devices are backward compatible.
** Note the supported data width is subject to pinmux constraints.
The main differences between the two devices with respect to USB is the integrated PHYs and the more flexible operation in the AM335x.
The AM37x requires an external PHY with both the USB-OTG and USB1-3 host ports. Also, the USB1-3 ports are only capable of host mode operation, at either high speed or full speed mode (not both).
The AM335x has 2 USB ports capable of host and OTG operations. Both ports have an integrated PHY.
The I2C ports are binary compatible same between the two devices.
AM37x supports 3 general I2C ports. The I2C ports can support up to 3.4Mbps high speed transmissions, along with the usual 100/400Kbps operation.
AM335x supports 3 general I2C ports. The ports only support 100/400Kbps operation. No high speed mode is supported.
The UART modules on both devices are functionality compatible with the TL16C750 (and TL16C550) UART. The primary differences between devices are the number of UARTs and supported capabilities.
AM37x has 4 UARTs. Only UART3 has IrDA capabilities. UART 4 does not support flow control.
AM335x has 6 UARTs, all of which support IrDA, CIR, and flow control. Full modem control is only available on 1 UART instance. AM335x allows 1 instance of UART rx/ tx lines to be muxed with USB DP/ DM lines.
AM37x has 5 McBSP ports and no McASP ports
AM335x has no McBSP ports and 2 McASP ports.
The McASP is a superset of the McBSP. It is suggested to use the McASP ports for McBSP functionality. Note the McASP ports on AM335x have less buffers for internal FIFO and audio loopback and no sidetone support.
The module does not exist on AM335x. It is suggested to use either I2C or GPIO for this type of functionality (eg, battery monitor).
The GPTimers on both devices are binary compatible.
AM37x has 11 32-bit GPTimers. Three GPTimers (GPTIMER1, GPTIMER2, and GPTIMER10) support 1-ms tick with 32,768 Hz functional clock generated. Only 4 GPTimers (GPT_8 - GPT_11) are pinned out.
AM335x supports seven (7) 32-bit GPTimers. One GPTimer (DMTIMER1) is specialized for accurate 1mS OS Ticks. Only 4 GPTimers (DMTIMER4 - DMTIMER7) are pinned out.
AM37x has 2 32-bit Watchdog Timers. AM335x has 1 32-bit Watchdog Timer.
32-kHz Sync Timer
The 32-kHz sync timer does not exist on AM335x.
The GPIO modules between the two devices are binary compatible. The only difference is in the number of banks and I/O capabilities.
AM37x supports 6 banks of GPIO signals. Each bank supports 32 GPIOs and two interrupts. All GPIOs are 1.8V I/Os, with the exception of those muxed with MMC1 which are 3.0V capable.
AM335x supports 4 banks of GPIO signals. Each bank supports 32 GPIOs and two interrupts. All GPIOs are 1.8V/3.3V capable, depending on which I/O group the pin falls in. Most LVCMOS IO`s on AM335x are configurable as GPIO.
New interfaces in AM335x
The following are new interfaces in the AM335x device that do not exist in AM37x. Any details about these interfaces can be found in the Technical Reference Manual for AM335x.
- CAN - Controller Area Network Interface
- PRUSS - Programmable Real-time Unit SubSystem
Pin and package
The AM37x and the AM335x devices are offered different mechanical packages. The physical dimensions and pin out of the packages are also different. The table below lists the variations between the AM37x and the AM335x devices.
|Device||Size (mm)||Pitch (mm)||No. of Pins||POP||Package Designator|
|AM37x||12 x 12 mm||0.5 mm top, 0.4 mm bottom||515||Supported||s-PBGA (CBP Suffix)|
|14 x 14 mm||0.65 mm top, 0.5 mm bottom||515||Supported||s-PBGA (CBC Suffix)|
|16 x 16 mm||0.65 mm||423||Not supported||s-PBGA (CUS Suffix)|
|AM335x||13 x 13 mm||0.65 mm||298||Not supported||s-PBGA (ZCE Suffix)|
|15 x 15 mm||0.80 mm, with VCA||324||Not supported||s-PBGA (ZCZ Suffix)|