RK3308
A quad Cortex-A35 audio SoC with an 8-channel ADC codec, hardware voice activity detection and a deep I2S/TDM/PDM/SPDIF set, at the cost of a 16-bit DRAM bus capped at 512 MB, 10/100 Ethernet, USB 2.0 only and no GPU, video codec, NPU, PCIe or camera input.
- CPU
- 4x Cortex-A35, 1.3 GHz (datasheet)
- GPU
- None
- NPU
- None
- Video
- None (RGB/MCU display only)
- PCIe
- None
What the RK3308 is for
Right for
- Far-field voice front ends: on-chip codec with up to 8 analog mic inputs, an 8-channel PDM input and a hardware VAD that can buffer the mic array before wake
- Multi-channel audio bridges and players: four 8-channel I2S/TDM controllers (two on pins, combinable into one 16-channel port), SPDIF in and out with HDMI ARC
- Low-cost headless Linux nodes: quad Cortex-A35, 10/100 MAC with RMII and two USB 2.0 ports; many boards are 256 or 512 MB DDR3 with eMMC or SPI NAND
- Two-chip audio designs with no DRAM routing: RK3308G and RK3308H put 64 MB DDR2 in the package (14 x 14 mm TFBGA355), RK3308H1 128 MB DDR3L (14 x 14 mm), RK3308H2 and RK3308H3 256 MB DDR3L (16 x 16 mm)
- Projects that want mainline Linux: SoC devicetree since Linux 5.5, Ethernet and USB since 5.14, the internal audio codec since 6.10
Wrong for
- Anything needing more than 512 MB of RAM: the DRAM interface is 16-bit, one rank, 512 MB maximum
- Video or graphics: the datasheet lists no GPU, no video decoder or encoder and no camera input; display is parallel RGB or MCU only
- Gigabit Ethernet, USB 3, PCIe or SATA: none are on the chip
- AI inference beyond what four A35 cores can do: there is no NPU
- HDMI or MIPI DSI output: the VOP drives a parallel RGB or MCU panel only
Cost and constraints
- Process re-spin: RK3308B-S and RK3308H-S are pin compatible with the older parts but run VDD_CORE and VDD_LOG at 0.9 V typical, leave USB_EXTR (C15) floating, need the RK816B-6 rather than RK816B-3 PMIC and need updated loader binaries
- Clock depends on the part: the RK3308 and RK3308B datasheets rate the CPU at 1.3 GHz, the RK3308B-S datasheet at 1.1 GHz, RK3308K at 1.2 GHz and the wide-temperature RK3308J and RK3308M at 1.0 GHz. Radxa rates its RK3308B boards at 1.0 GHz, mainline Linux tops out at 1008 MHz, and the Rockchip S-version software table tops out at 1104 MHz
- Board-level BOM is small: Radxa boards run the SoC from discrete PWM-controlled bucks with one x16 DDR3 chip, no PMIC required
- Software splits between Rockchip BSP kernels (4.4, 4.19, 5.10, 6.1 branches) and mainline; mainline has no display (VOP), PDM, VAD or thermal node in rk3308.dtsi as of 7.3-rc7
Inside the RK3308
Drawn by Groundplane from the datasheet rev 1.5. Not Rockchip artwork.
- DDR2/DDR3/DDR3L/LPDDR2 x16
- eMMC 5.1, 8-bit, HS200
- SD 3.0, 4-bit
- SPI NOR/NAND, async NAND
- 4x Cortex-A35 to 1.3 GHz
- 32 KB + 32 KB L1 per core
- 256 KB shared L2
- NEON, FPU, crypto extensions
- Codec: 8-ch ADC, stereo DAC
- Hardware VAD
- 4x I2S/TDM 8-ch, 2x I2S 2-ch
- PDM 8-ch, SPDIF RX and TX
- 16-bit DDR controller, 512 MB
- 64 MB DDR2 in G and H parts
- 256 KB SRAM, 32 KB ROM
- VOP, 2 layers, to 1080p
- RGB or MCU panel
- Crypto: AES, SHA, RSA/ECC
- TRNG, 4 Kbit OTP
- TrustZone, secure boot
- 4 PLLs, 24 MHz oscillator
- 2x DMAC, 12 timers, watchdog
- SARADC 6-ch, 2 temp sensors
- 10/100 Ethernet MAC, RMII
- USB 2.0 OTG
- USB 2.0 host
- SDIO 3.0 for Wi-Fi
- 8 analog mic inputs
- Headphone and line out
- I2S/TDM, PDM, SPDIF, ARC
- RGB666/RGB888 or MCU LCD
- 5x UART, 4x I2C, 3x SPI
- PWM, SARADC, GPIO
Read from the documents
Each value names the document it was read from.
| CPU | 4x Cortex-A35 (Armv8-A) with NEON, FPU and crypto extensions; 32 KB I + 32 KB D L1 per core, 256 KB shared L2; per-core power domains; max 1.3 GHz | Datasheet Rev 1.5, 1.2.1, Table 3-2 |
|---|---|---|
| GPU | None listed | Datasheet Rev 1.5 |
| NPU | None listed | Datasheet Rev 1.5 |
| Video decode and encode | None listed: no video codec in the feature list or block diagram | Datasheet Rev 1.5 |
| Memory | DDR2-1066, DDR3-1600, DDR3L-1600 or LPDDR2-1066 (one type at a time); 16-bit, 1 rank, 512 MB maximum. RK3308G/RK3308H: 64 MB DDR2 in package, no external DRAM interface | Datasheet Rev 1.5, 1.2.3, 1.2.4 |
| Storage and boot | eMMC 4.41 to 5.1 (8-bit, HS200, no command queue), SD 3.0 4-bit, SPI flash x1/x2/x4, 8-bit async NAND with 16-bit/1 KB ECC. BootROM boots NAND, eMMC, SPI flash or SD; download over USB OTG (device mode) | Datasheet Rev 1.5, 1.2.3, 1.2.4 |
| Display | One VOP, two layers: parallel RGB 18-bit (RGB666) or 16-bit (RGB565), MCU interface; max output 1080p. RK3308B adds 24-bit RGB888 | Datasheet Rev 1.5, 1.2.6; RK3308B datasheet 1.2.6 |
| Camera | None listed | Datasheet Rev 1.5 |
| Audio (digital) | 2x I2S 2-channel (one on pins, one to the codec); 4x I2S/TDM 8-channel (two on pins, combinable as one 16-channel); PDM 8-channel (4 data lines, 8 mono mics); SPDIF TX and RX with HDMI ARC; all to 192 kHz (TDM 48 kHz at 8 channels) | Datasheet Rev 1.5, 1.2.7 |
| Audio codec | 24-bit ADC, up to 8 mic channels, differential or single-ended; 24-bit stereo DAC for headphone (18 mW into 16 ohm) and line out; ALC, two mic bias outputs, jack detect | Datasheet Rev 1.5, 1.2.7, 3.9 |
| Voice activity detection | Hardware VAD on one mic (analog, I2S or PDM source) with band filtering and amplitude detection; buffers multi-mic data in shared system SRAM before or after the trigger | Datasheet Rev 1.5, 1.2.7 |
| PCIe | None | Datasheet Rev 1.5 |
| USB | 1x USB 2.0 OTG, 1x USB 2.0 host (EHCI/OHCI), HS/FS/LS | Datasheet Rev 1.5, 1.2.8 |
| Ethernet | 1x 10/100 MAC, RMII (external PHY), Wake-on-LAN and VLAN tag detection | Datasheet Rev 1.5, 1.2.8 |
| Other I/O | SDIO 3.0 4-bit, 3x SPI, 4x I2C (to 1 Mbit/s), 5x UART (to 4 Mbps), 4x PWM (RK3308B: three 4-channel PWM controllers), 6-channel 10-bit SARADC, 2 temperature sensors, 4 Kbit OTP; RK3308B adds a 1-Wire controller | Datasheet Rev 1.5, 1.2.5, 1.2.8, 1.2.9; RK3308B datasheet 1.2.5, 1.2.8 |
| Security | TrustZone, crypto engine (AES, DES/TDES, SHA-1/256/512, MD5, HMAC, PKA to 4096-bit RSA/ECC), TRNG, secure OTP, secure boot, DDR scrambling | Datasheet Rev 1.5, 1.2.5 |
| Power | CORE_VDD 0.95 to 1.10 V (1.00 V typ), LOGIC_VDD 0.90 to 1.10 V; DDR IO 1.8 V (DDR2), 1.5 V (DDR3), 1.35 V (DDR3L), 1.2 V (LPDDR2); IO domains 3.3 V or 1.8 V. S-version parts: 0.9 V typ on VDD_CORE and VDD_LOG | Datasheet Rev 1.5, Table 3-2; S-version note section 1 |
| Package | TFBGA355, 0.65 mm pitch, 0.3 mm ball: 13 x 13 mm (RK3308, RK3308B), 14 x 14 mm (RK3308G, RK3308H); 1190 per tray | Datasheet Rev 1.5, 1.2.9, 2.1 |
| Thermal | Theta-JA 45, theta-JB 35, theta-JC 15 C/W (RK3308); 44, 34, 14 C/W (RK3308G); simulated on a 4-layer board; Tj max 125 C; ambient 0 to 85 C. Other parts per their own datasheets: RK3308B-S, RK3308H1 and RK3308K -20 to 85 C; RK3308J and RK3308M -40 to 85 C | Datasheet Rev 1.5, 4.1, 4.2, Table 3-2 |
Variants
| RK3308 | Original part: external 16-bit DDR2/DDR3/DDR3L/LPDDR2 to 512 MB, four PWMs, RGB666/RGB565 or MCU display. TFBGA355 13 x 13 mm. | Datasheet Rev 1.5 |
|---|---|---|
| RK3308G | RK3308 with a 64 MB DDR2 die in the package and no DRAM interface; the DDR balls become VSS or DDR_VDD. 14 x 14 mm TFBGA355, and Rockchip states it can share a PCB design with the RK3308. | Datasheet Rev 1.5 |
| RK3308B | Same package and pinout family as the RK3308; adds 24-bit RGB888 display output, three 4-channel PWM controllers in place of four PWMs, and a 1-Wire controller. Same 1.3 GHz rating. This is the part on current Radxa, Firefly and Sakura Pi boards. | Datasheet Rev 1.2 |
| RK3308H | RK3308B with 64 MB DDR2 in the package, 14 x 14 mm, no external DRAM interface. | Datasheet Rev 1.2 |
| RK3308B-S / RK3308H-S | Process re-spin of the RK3308B and RK3308H (2021). Pin to pin compatible, but VDD_CORE, VDD_LOG, PLL and USB 1.0 V rails drop to 0.9 V typical, USB_EXTR (ball C15) is left floating instead of a 133 ohm resistor, the RK816B-6 PMIC replaces the RK816B-3, and IO drive strengths differ. Firmware must use rk3308_ddr v2.05, miniloader v1.32, bl31 v2.24 or later to run on both. The RK3308B-S datasheet (Rev 1.1, 2023-09-22) rates the CPU at 1.1 GHz and ambient at -20 to 85 C, and adds RK3308H1-S with 128 MB DDR3L in package. | Errata V1.0.1 |
| RK3308J / RK3308M | Wide-temperature parts in the 13 x 13 mm TFBGA355: -40 to 85 C ambient with the CPU rated 1.0 GHz (RK3308J datasheet Rev 1.1, 2023-07-12; RK3308M Rev 1.0, 2023-08-10). Firefly uses them on its Core-3308JY (industrial) and Core-3308MY (automotive) modules. | Datasheet Rev 1.1 |
| RK3308K / RK3308GK | Extended-temperature parts: -20 to 85 C ambient, CPU rated 1.2 GHz. RK3308K is 13 x 13 mm with external DRAM; RK3308GK adds 64 MB DDR2 in a 14 x 14 mm package (RK3308K datasheet Rev 1.3, 2020-09-21). | Datasheet Rev 1.3 |
| RK3308H1 / RK3308H2 / RK3308H3 | In-package DDR3L instead of DDR2, no external DRAM interface, CPU rated 1.3 GHz. RK3308H1: 128 MB, 14 x 14 mm, -20 to 85 C (Rev 1.0, 2023-09-22). RK3308H2 and RK3308H3: 256 MB, 16 x 16 mm, 0 to 85 C (H2 Rev 1.0, 2020-06-05; H3 Rev 1.2, 2025-07-31), so they are not footprint compatible with the 13 x 13 or 14 x 14 mm parts. | Datasheet Rev 1.2 |
What to watch when you design with it
Power and PMIC
The RK3308 has two core rails: CORE_VDD (CPU, 1.00 V typ, DVFS) and LOGIC_VDD (1.00 V typ), plus DDR IO and 3.3/1.8 V IO domains. Radxa boards use discrete bucks rather than a PMIC: on the ROCK Pi S v1.3 VDD_CORE is a PWM-controlled buck (SY8089 or ETA3409, output set by duty cycle, trace sized for 1.5 A), VDD_LOG is a fixed buck, PLL and USB 1.0 V supplies tap VDD_LOG, and VCC_DDR defaults to 1.5 V. Rockchip pairs the RK816B-3 PMIC with RK3308, RK3308G, RK3308B and RK3308H, and the RK816B-6 with the S-version parts. Combining VDD_CORE and VDD_LOG on one regulator caps the CPU at 912 MHz (1.1 V, older parts) or 816 MHz (1.0 V, S-version).
Sources: Datasheet Rev 1.5, Errata V1.0.1, Board schematic v1.3, lcsc.com
S-version migration
Boards built for the RK3308B can take the RK3308B-S with three changes: VDD_LOG to 0.9 V (Rockchip reference: feedback resistor R2108 to 75K), VDD_1V0 feedback resistor to 51K, and ball C15 (USB_EXTR) left open with no 133 ohm resistor. Radxa made exactly these changes in ROCK Pi S v1.3 (R1400 not fitted, R2204 to 75K). Software must carry the S-version patch and newer rkbin loaders, and IO drive strengths for Ethernet, Wi-Fi, flash and SD need retesting.
Sources: Errata V1.0.1, Other V1.0.0, docs.radxa.com
DDR
One x16 DRAM on a 16-bit, single-rank bus, 512 MB maximum; Radxa boards use a single Samsung K4B2G1646F DDR3 (2 Gb) part for 256 MB. The datasheet allows DDR3-1600, but the Rockchip S-version loaders listed run DDR at 393, 451 or 589 MHz and the S-version DMC table tops out at 590 MHz. RK3308G and RK3308H remove the routing entirely: the DDR balls become ground or DDR_VDD and the same footprint carries 64 MB DDR2 in package.
Sources: Datasheet Rev 1.5, Other V1.0.0, Board schematic v1.3
Audio front end
The codec takes up to 8 differential or single-ended analog mics with two programmable bias outputs (up to 0.85 x AVDD3V3) and drives headphones directly (18 mW into 16 ohm). CODEC_AVDD_3V3 and CODEC_AVDD_1V8 are separate supplies. Radxa documents analog silicon, electret, I2S and PDM mic reference circuits for the rCore-RK3308, and Firefly sells a PDM mic array kit for the ROC-RK3308-CC.
Sources: Datasheet Rev 1.5, Other Rev 1.1, wiki.t-firefly.com
Boot and maskrom
The BootROM tries async NAND, eMMC, SPI flash and SD, and falls back to USB OTG download (maskrom). With empty storage and no SD card a board stays in maskrom. Radxa boards have a maskrom button (hold while connecting the Type-C OTG port); the ROC-RK3308-CC needs two test points shorted; the rCore-RK3308 enters maskrom when its maskrom pins are pulled up. Flash with rkdeveloptool or RKDevTool and an rk3308 loader.
Sources: Datasheet Rev 1.5, Other Rev 1.1, docs.radxa.com, wiki.t-firefly.com
Thermal
Simulated theta-JA is 45 C/W (RK3308) and 44 C/W (RK3308G) on a 4-layer JEDEC-size board, with junction to stay below 125 C and ambient rated to 85 C. Board vendors rate their RK3308B products from -20 to 60 C (Firefly ROC-RK3308B-CC Plus) or 0 to 70 C (ArmSoM P2 Pro). Sakura Pi documents running at 1.3 GHz only after raising the CPU rail above its 1.0 V default and recommends a heatsink when doing so.
Sources: Datasheet Rev 1.5, Other V1.0, docs.armsom.org, docs.sakurapi.org
Gotchas
Check IO domain voltages in the devicetree against the hardware: Rockchip warns that a software IO domain setting that differs from the supply can damage the pins, and that many customers include the EVB dtsi wholesale. The VOP datasheet limit is 1080p while Rockchip product page and board vendors quote 720p for RGB panels. The Ethernet MAC is RMII only and needs an external PHY (Radxa uses the RTL8201F).
Sources: Errata V1.0.1, Datasheet Rev 1.5, Product brief, Board schematic v1.3
Layout guides for the RK3308's interfaces
Public layout guidance for each interface this chip has, from vendors who publish it, plus our calculators.
DDR3 / DDR3L
Fly-by command/address with termination at the end of the chain, point-to-point data lanes matched to their strobe, and a clean VREF. ST recommends 55 ohm single-ended and 100 ohm differential for DDR3 and DDR3L on STM32MP1 boards, and shows that a 4-layer board is possible with strict layer allocation.
- STM32MP1 Series DDR memory routing guidelinesSTMicroelectronics, AN5122, 3, 2019
- DDR3 Design Requirements for KeyStone DevicesTexas Instruments, SPRABI1, D, 2022
- SL2610 General PCB Design and DDR3L/DDR4 & LPDDR4(x) Interface Layout GuidelinesSynaptics, PN 506-001629-01, A, 2025
- DDR length matching calculatorGroundplane calculator
eMMC
A single-ended bus: CLK, CMD, DAT0 to DAT7 and, for HS400, the data strobe. TI and Synaptics both route it at 50 ohm single-ended, match the group, and keep stubs short; Synaptics places a 22 or 33 ohm series resistor on CLK and STRB. At HS400 TI also checks the eMMC I/O supply impedance, not just the traces.
- AM62Px eMMC HS400 Board Design and Simulation GuidelinesTexas Instruments, SPRADP5, A, 2026
- Astra Machina Foundation Series eMMC ConfigurationSynaptics, PN 506-001594-01, D
- i.MX28 Layout and Design GuidelinesNXP (Freescale), AN4215, 0, 2010
SD card / SDIO
Single-ended CLK, CMD and four data lines over a solid ground plane, at constant trace width and matched length. NXP asks for clock-to-neighbor spacing greater than twice the trace height above the plane and 1.5 times for data and CMD, with 45 degree bends. UHS modes switch the I/O to 1.8 V, so a level translator often sits next to the socket.
- NVT4557/NVT4558/NVT4858 voltage-level translator layout guidelineNXP, AN13158, 1.1, 2022
- i.MX28 Layout and Design GuidelinesNXP (Freescale), AN4215, 0, 2010
- SD Physical Layer Simplified SpecificationSD Association, 9.10, 2023
PCIe
AC-coupled differential lanes routed with no stubs, minimal vias and back-drilled or blind vias where speed demands, with lane-to-lane skew handled by the receiver. Targets differ by guide: TI Jacinto 7 uses 85 ohm differential for lanes and 100 ohm for the reference clock, while TI's earlier SoC guide tabulates 100 ohm and, for some devices, 95 ohm. Match the target to your connector and stackup.
- Jacinto7 AM6x, TDA4x, and DRA8x High-Speed Interface Design GuidelinesTexas Instruments, SPRACP4, A, 2024
- High-Speed Interface Layout GuidelinesTexas Instruments, SPRAAR7, J, 2023
USB 2.0
One D+/D- pair at 90 ohm differential, routed in parallel for its whole length with minimal deviations at the connector and package. NXP keeps clocks and periodic signals at least 50 mils away and other signals at least 20 mils away from the pair.
- High-Speed Layout Guidelines for Signal Conditioners and USB HubsTexas Instruments, SLLA414, A, 2026
- High-Speed Interface Layout GuidelinesTexas Instruments, SPRAAR7, J, 2023
- i.MX28 Layout and Design GuidelinesNXP (Freescale), AN4215, 0, 2010
HDMI
Four TMDS pairs (three data, one clock) at 100 ohm differential, as both TI guides state, with tight intra-pair matching and as few vias as possible between the SoC and the connector. HDMI also needs 5 V supply switching, DDC and CEC level handling, hot-plug detect and ESD at the connector.
- High-Speed Layout Guidelines for Signal Conditioners and USB HubsTexas Instruments, SLLA414, A, 2026
- High-Speed Interface Layout GuidelinesTexas Instruments, SPRAAR7, J, 2023
- TPD12S016 PCB Layout Guidelines for HDMI ESDTexas Instruments, SLLA324, 2012
Ethernet (RGMII / RMII)
TI routes MAC-to-PHY (MII family) traces at 50 ohm single-ended, under 6 inches, matched within 20 mils for gigabit, and the PHY-side MDI pairs at 100 ohm differential. RGMII also needs a 1.5 to 2.0 ns clock-to-data delay, added on the board or inside the MAC or PHY (RGMII-ID); decide which before layout so it is not applied twice.
- Ethernet PHY PCB Design Layout ChecklistTexas Instruments, SNLA387, 2021
- PCB Design Guideline for RGMII InterfaceRenesas, R01AN6272EJ0141, 1.41, 2026
- i.MX28 Layout and Design GuidelinesNXP (Freescale), AN4215, 0, 2010
Board-level design guides
Impedance and timing, power, thermal and ESD guidance that applies to any board around this chip.
Impedance and timing
Every high-speed interface on the board comes down to the same two numbers: the trace impedance your stackup actually gives, and the delay each trace adds. Set the stackup with your fab first, then route to its impedance table and match lengths in time, not millimeters, where the layers differ.
- High-Speed Interface Layout GuidelinesTexas Instruments, SPRAAR7, J, 2023
- PCB impedance calculatorGroundplane calculator
- PCB propagation delay calculatorGroundplane calculator
Power delivery
For each switching regulator, place and route the input capacitor first, keep the switching current loop small, and keep the switch node short. Give the SoC rails solid planes and decoupling at the balls, and size current-carrying copper and vias for the real load.
- Five steps to a great PCB layout for a step-down converterTexas Instruments, SLYT614, 2015
- AN-1149 Layout Guidelines for Switching Power SuppliesTexas Instruments, SNVA021, C, 2013
- AN-1229 SIMPLE SWITCHER PCB Layout GuidelinesTexas Instruments, SNVA054, C, 2013
- Buck converter calculatorGroundplane calculator
- LDO power dissipation calculatorGroundplane calculator
- PCB trace width calculatorGroundplane calculator
- Via current calculatorGroundplane calculator
Thermal
Theta-JA is measured on a JEDEC test board that carries most of the heat, so it does not transfer directly to a product board; use it to compare packages and use the psi metrics for estimates. Thermal vias under the package, copper area and copper thickness move the most heat into the board.
- Semiconductor and IC Package Thermal MetricsTexas Instruments, SPRA953, D, 2024
- AN-2020 Thermal Design By Insight, Not HindsightTexas Instruments, SNVA419, C, 2013
- Heatsink thermal resistance calculatorGroundplane calculator
- LDO power dissipation calculatorGroundplane calculator
ESD protection
Place the TVS as close to the connector as design rules allow, route from the connector to the TVS with no stub, and keep the protected IC further from the TVS than the TVS is from the connector. Choose parts by clamping performance and by capacitance low enough for the interface speed.
- ESD Protection Layout GuideTexas Instruments, SLVA680, A, 2022
- Reading and Understanding an ESD Protection Data SheetTexas Instruments, SLLA305, A
- TPD12S016 PCB Layout Guidelines for HDMI ESDTexas Instruments, SLLA324, 2012
- PCB conductor spacing calculator (IPC-2221)Groundplane calculator
Rockchip's hardware design guide
Rockchip's hardware design guide, EVB reference schematics and DDR templates come from Rockchip or an authorized agent, usually under NDA, or through your SoM vendor. We do not link copies circulating elsewhere. The vendor schematics and open designs on the Boards tab are real, shipped layouts on the RK3308 and the best public reference.
BSP, mainline and toolkits
| Area | Status | Links |
|---|---|---|
| Vendor BSP kernel | Rockchip carries RK3308 and RK3308B board files in its develop-4.4, 4.19, 5.10 and 6.1 kernel branches (EVB, voice module, partybox and AI-VA reference boards). Board vendors ship 4.4 (Radxa stable-4.4-rockpis at 4.4.143, Firefly RK3308 SDK) and 5.10 (ArmSoM P2 Pro BSP at 5.10.110, Luckfox Nova SDK manifest luckfox-linux-5.10-rk3308).Checked 2026-10-13 | |
| Mainline Linux | Clock driver in 5.4; SoC devicetree with the Rockchip EVB and Firefly ROC-RK3308-CC in 5.5; NAND controller node 5.12; Ethernet (GMAC) and USB 5.14; SPI flash controller 5.16; ROCK Pi S 6.0; internal audio codec driver and node 6.10; OTP and IO voltage domains plus Radxa ROCK S0 6.11; Banana Pi P2 Pro 6.13; Sakura Pi RK3308B 6.17. As of 7.3-rc7 rk3308.dtsi has no VOP (display), PDM, VAD or thermal sensor node; cpufreq tops out at 1008 MHz.Checked 2026-10-13 | |
| U-Boot | Mainline U-Boot has RK3308 support since v2020.01 (evb-rk3308, roc-cc-rk3308 defconfigs), ROCK Pi S since v2023.04 and ROCK S0 since v2024.10. Vendor U-Boot 2017.09 in the Rockchip-based SDKs (Luckfox Nova).Checked 2026-10-13 | |
| Distributions | Armbian builds ROCK Pi S, ROCK S0, Sakura Pi RK3308B and Luckfox Nova on its mainline-based rockchip64 family. Radxa publishes Debian bookworm CLI images (ROCK Pi S build b40, ROCK S0 build 6). OpenWrt supports the ROCK Pi S. Firefly ships Buildroot and Ubuntu firmware; Banana Pi and ArmSoM ship Debian 11, Buildroot and iStoreOS.Checked 2026-10-13 | |
| Community | Radxa forum and docs carry most English-language RK3308 discussion; Firefly documents voice assistant integrations (Alexa, DuerOS, AISpeech, iFlytek) for the ROC-RK3308-CC.Checked 2026-10-13 |
RK3308 on GitHub
Repositories for this chip: vendor code, mainline work, toolkits, distributions and open hardware.
- Vendor BSPradxa-build/rock-pi-sRadxa image recipe for the RK3308 ROCK Pi S. Last commit 2026-08.
- Vendor BSPradxa-build/rock-s0Radxa image recipe for the RK3308 ROCK S0. Last commit 2026-08.
- Vendor BSPradxa-build/radxa-rcore-rk3308-ioRadxa image recipe for the rCore-RK3308 module on its IO board. Last commit 2026-08.
- Vendor BSPArmSoM/armsom-p2pro-bspArmSoM BSP for the RK3308B-S based P2 Pro board. Last commit 2023-07.
- Vendor BSPJeffyCN/meta-rockchipYocto BSP layer maintained by a Rockchip engineer, with RK3308 machine configs. Last commit 2026-10.
- Kernelrockchip-linux/kernelRockchip BSP kernel; RK3308 has about 50 device trees on develop-5.10 and develop-6.1 and more on develop-6.6. Last commit 2026-08.
- Kernelradxa/kernelRadxa BSP kernel; branch stable-4.4-rockpis is the ROCK Pi S vendor kernel. Last commit 2026-10.
- Kerneltorvalds/linuxMainline Linux has rk3308.dtsi with ROCK Pi S, ROCK S0, ROC-CC and Banana Pi P2 Pro boards. Last commit 2026-10.
- Bootloaderrockchip-linux/u-bootRockchip U-Boot; next-dev has arch/arm/mach-rockchip/rk3308 and several rk3308 defconfigs. Last commit 2026-08.
- Bootloaderrockchip-linux/rkbinDDR init, loaders and BL31; bin/rk33 holds about 16 rk3308 binaries covering the B and H variants. Last commit 2026-08.
- Bootloaderu-boot/u-bootMainline U-Boot with evb-rk3308_defconfig and RK3308 SoC support. Last commit 2026-10.
- Distributionarmbian/buildArmbian build framework with ROCK Pi S, ROCK S0, Sakura Pi and Luckfox Nova RK3308 configs. Last commit 2026-10.
- Distributionopenwrt/openwrtOpenWrt rockchip/armv8 target builds the ROCK Pi S on RK3308. Last commit 2026-10.
- DistributionMichaIng/DietPiMinimal Debian images with a ROCK Pi S build for RK3308. Last commit 2026-10.
- Open hardwareradxa/radxa-som-projectsRadxa reference carrier designs in Altium; the rcore-rk3308 folder covers the RK3308 module. Last commit 2026-09.
- Open hardwareTWINKLY09/Vocal-Assistant-based-on-linux-for-HomeAssistantOpen hardware voice assistant on an RK3308B with a 4 mic I2S array, with EasyEDA design files. Last commit 2026-06.
- Toolsrockchip-linux/rkdeveloptoolRockchip open source USB flashing tool for maskrom and loader mode, the Linux and macOS alternative to RKDevTool. Last commit 2025-03.
- Toolsxboot/xrockLow level maskrom and loader mode tool that can also init DDR and run code over USB; chip support is listed in its README. Last commit 2026-08.
- Toolslinux-rockchip/rkflashtoolCommunity rkflashtool fork for reading and writing flash over USB in loader mode; its device table includes RK3308. Last commit 2025-09.
RK3308 system on modules
Any of these can sit on a carrier board we design.
| Module | Vendor | Connector | RAM | Design files | Price | Buy |
|---|---|---|---|---|---|---|
| rCore-RK3308 (formerly ROCK Pi S Core) | Radxa | Stamp footprint (castellated) | 256 or 512 MB DDR3 | schematic PDF (v2.20), component placement PDF, datasheet with interface reference circuits | ||
| Core-3308BY / Core-3308JY / Core-3308MY | Firefly | 136-pin stamp hole, 1.2 mm pitch | 256 or 512 MB DDR3 | pin definition in the specification PDF; no download files listed | USD 69 (Firefly store, Core-3308BY 512 MB / 8 GB) | |
| DSOM-050R | Dusun | 136-pin stamp hole, 1.2 mm pitch | 256 or 512 MB DDR3 | carrier board schematic (Google Drive) | ||
| Ariaboard RK3308 core board | Shanghai Novotech (Ariaboard) | 256 or 512 MB DDR3 | none found; kernel, U-Boot, Buildroot and SDK sources on GitHub |
Every public RK3308 board
| Board | Vendor | Type | RAM | Notable I/O | Design files | Price | Buy |
|---|---|---|---|---|---|---|---|
| ROCK Pi S | Radxa | SBC, 1.7 x 1.7 inch SBC | 256 or 512 MB DDR3 | 10/100 Ethernet, PoE with HAT, USB-A host, USB-C OTG, 2x 26-pin headers, Optional Wi-Fi 4 / BT 4 | schematic PDF (v1.0 to v1.3), component placement PDF, 2D DXF (v1.0), 3D STEP (v1.5) | ||
| ROCK Pi S0 (ROCK S0) | Radxa | SBC, Ultra-small SBC, 40-pin header | 256 or 512 MB DDR3 | 10/100 Ethernet, USB OTG and host on 1.25 mm connectors, eMMC to 8 GB, Wi-Fi 4 / BT 5, Maskrom and reset keys | schematic PDF (v1.1, v1.2), component placement PDF, 2D DXF, 3D STEP | ||
| ROC-RK3308B-CC Plus | Firefly | SBC, 95.2 x 60 mm | 128 to 512 MB DDR3 | RJ45 10/100, 8 analog mics plus loopback, RGB/MCU LCD, Wi-Fi 2.4 GHz | none found on the Firefly download page | USD 89 (Firefly store, 512 MB / 8 GB) | |
| ROC-RK3308-CC | Firefly | SBC, Compact SBC (original RK3308) | 10/100 Ethernet, PoE, USB-C OTG and power, Wi-Fi / BT, PDM mic array kit | wiki lists a V10 schematic, but the current download page offers none | |||
| EC-R3308CC | Firefly | SBC, Fanless mini PC, 100 x 84 x 20 mm | 512 MB DDR3 (128 to 512 MB options) | 2x RJ45 10/100, USB 2.0, USB-C OTG, Wi-Fi 2.4 GHz, 3.5 mm audio | none | USD 109 (Firefly store, 512 MB / 8 GB) | |
| iHC-3308GW | Firefly | SBC, Industrial gateway, 99.4 x 84 x 35.2 mm | 256 to 512 MB DDR3 | 2x RJ45 10/100, RS232, 3x RS485, CAN, Optional 4G Cat1, NB-IoT or LoRa, 12 V DC input | none | USD 139 (Firefly store, 512 MB / 8 GB, Wi-Fi) | |
| Banana Pi BPI-P2 Pro / ArmSoM P2 Pro | Banana Pi (SinoVoip) / ArmSoM | SBC, 65 x 52.5 mm | 512 MB DDR3 | RK3308B-S, 10/100 Ethernet, 802.3af PoE option, AP6256 Wi-Fi 5 / BT 5, 40-pin and 12-pin headers, 8 mics on header | schematic, 2D drawing and SMD placement (Google Drive, linked from ArmSoM docs) | USD 20 (ArmSoM store, lowest listed) | |
| Sakura Pi RK3308B | Sakura Pi | SBC, Pi Zero W compatible 40-pin layout | 512 MB DDR3 (256 MB per the mainline commit) | RGB666 LCD, Wi-Fi 5 / BT 4.2, eMMC 0, 8 or 16 GB, 4x WS2812 LEDs | schematic PDF (hw2.0, 2025-03-05), interactive BOM (HTML), 3D STEP | ||
| Luckfox Nova / Nova W | Luckfox | SBC, SBC with 2x 26-pin headers | 512 MB DDR3 | RJ45 10/100, PoE module option, USB-C and USB-A, Onboard mic, 2 W speaker header, Nova W: Wi-Fi 6 / BT 5.2 | none found | USD 28.99 (Luckfox store, lowest listed) | |
| NAPI-C / NAPI-P | NAPI | SBC, 43 x 43 mm (NAPI-P: pin headers instead of connectors) | 512 MB | 10/100 Ethernet, PoE ready, USB-A and USB-C, 3x UART, SPI, 2x I2C, 4 GB NAND | GPIO description, mechanical drawings and block diagram PDFs |
Prices and links as checked on the dates in our data; the latest check on this page was 2026-10-13.
Boards with published design files
| Project | Author | Files | Tool | License |
|---|---|---|---|---|
| Open-hardware voice assistant (rCore-RK3308 carrier stack) | TWINKLY09 | schematic PDFs (5 boards), EasyEDA Pro project, Altium export, Gerbers, BOM, pick and place, STEP | EasyEDA | CERN-OHL-P v2 (hardware), MIT (software) |
Buying the chip
Rockchip's site lists no RK3308 distributors. No public LCSC listing with price and stock for any RK3308 variant could be confirmed on 2026-10-13. Board vendors (Radxa, Firefly, Luckfox, Banana Pi, Sakura Pi) still sell RK3308B and RK3308B-S boards, which suggests continued supply of the S-version silicon.
- Macro Group (RK3308)
- Russian distributor listing the RK3308 (TFBGA355) with the Rev 1.5 datasheet; price on request (the listed price is a placeholder).
- Module route: Radxa rCore-RK3308, Firefly Core-3308BY, Dusun DSOM-050R
- Stamp-hole modules with power, DDR3 and storage on board; Firefly lists the Core-3308BY at USD 69 (512 MB / 8 GB). Avoids BGA and DDR layout.
Datasheet, TRM and design documents
Linked where they are publicly hosted; we do not rehost Rockchip documents. These are third-party documents: we are not responsible for their accuracy, availability or confidentiality status. Disclosure.
- DatasheetRockchip RK3308 Datasheet (RK3308, RK3308G)Rev 1.5 · 2019-01-21 · hosted by Macro Group · checked 2026-10-13
- DatasheetRockchip RK3308 Datasheet (RK3308, RK3308G; newest, marking update only over Rev 1.5)Rev 1.6 · 2019-09-27 · community mirror (rockchip.fr), not hosted by Rockchip · checked 2026-10-13
- DatasheetRockchip RK3308B-S Datasheet (RK3308B-S, RK3308H-S, RK3308H1-S)Rev 1.1 · 2023-09-22 · community mirror (rockchip.fr), not hosted by Rockchip · checked 2026-10-13
- DatasheetRockchip RK3308J Datasheet (the listing also has RK3308M Rev 1.0, 2023-08-10)Rev 1.1 · 2023-07-12 · community mirror (rockchip.fr), not hosted by Rockchip · checked 2026-10-13
- DatasheetRockchip RK3308K Datasheet (RK3308K, RK3308GK)Rev 1.3 · 2020-09-21 · community mirror (rockchip.fr), not hosted by Rockchip · checked 2026-10-13
- DatasheetRockchip RK3308H3 Datasheet (the listing also has RK3308H1 Rev 1.0, RK3308H1-S Rev 1.0 and RK3308H2 Rev 1.0)Rev 1.2 · 2025-07-31 · community mirror (rockchip.fr), not hosted by Rockchip · checked 2026-10-13
- DatasheetRockchip RK3308B Datasheet (RK3308B, RK3308H)Rev 1.2 · 2019-05-09 · hosted by Sakura Pi · checked 2026-10-13
- DatasheetRockchip RK3308 Datasheet (first release, many values TBD)Rev 1.0 · 2018-02-27 · hosted by Radxa · checked 2026-10-13
- TRMRockchip RK3308 Technical Reference Manual Part 1Rev 1.1 · 2018-08-10 · hosted by Radxa · checked 2026-10-13
- TRMRockchip RK3308 Technical Reference Manual Part 2Rev 1.1 · 2018-08-10 · hosted by Radxa · checked 2026-10-13
- ErrataRK3308 Series S-Version Chip Hardware Design Modification IntroductionV1.0.1 · 2021-10-18 · hosted by Radxa · checked 2026-10-13
- OtherRK3308B-S and RK3308H-S Software Compatibility Introduction (security level: public)V1.0.0 · 2021-10-16 · hosted by Radxa · checked 2026-10-13
- Product briefRockchip RK3308 product pagehosted by Rockchip · checked 2026-10-13
- Board schematicROCK Pi S v1.3 schematicv1.3 · 2019-09-10 · hosted by Radxa · checked 2026-10-13
- Board schematicROCK Pi S0 v1.2 schematicv1.2 · hosted by Radxa · checked 2026-10-13
- Board schematicrCore-RK3308 schematicv2.20 · hosted by Radxa · checked 2026-10-13
- OtherRadxa rCore-RK3308 datasheet (RAD-DOC-0073), with audio, Ethernet and maskrom reference circuitsRev 1.1 · 2025-04-28 · hosted by Radxa · checked 2026-10-13
- Board schematicSakura Pi RK3308B hw2.0 schematic2025-03-05 · hosted by Sakura Pi · checked 2026-10-13
- OtherFirefly ROC-RK3308B-CC Plus specification (Chinese)V1.0 · 2024-02-21 · hosted by Firefly · checked 2026-10-13
- OtherFirefly Core-3308BY / JY / MY specification with pin definition (Chinese)V1.3 · 2024-03-21 · hosted by Firefly · checked 2026-10-13
Questions about the RK3308
Not the RK3308 itself. We have designed and brought up boards on the Rockchip RV1106, RV1126, RV1126B, RK3566, RK3568, RK3576 and RK3588, and on the Allwinner T507 and A527/T527. The work carries over: power tree, DDR and high-speed layout, bring-up and the BSP, read against this chip's own datasheet.
The distributor Macro Group hosts RK3308 Rev 1.5 (2019-01-21), covering the RK3308 and RK3308G; the newest revision, Rev 1.6 (2019-09-27), only updates the marking information and is on the rockchip.fr community mirror. The RK3308B datasheet is Rev 1.2 (2019-05-09), covering the RK3308B and RK3308H, hosted by Sakura Pi. Datasheets for RK3308B-S, RK3308J, RK3308K, RK3308M and RK3308H1/H2/H3 are only on the mirror. Radxa hosts the TRM Rev 1.1 (Part 1 and Part 2) and the Rockchip notes for the S-version parts.
The RK3308B adds 24-bit RGB888 display output, twelve PWM channels in three controllers and a 1-Wire controller over the RK3308, in the same TFBGA355. The RK3308B-S is a 2021 process re-spin of the RK3308B: pin compatible, but core and logic rails at 0.9 V, ball C15 left floating, the RK816B-6 PMIC variant, newer loaders required, and a 1.1 GHz CPU rating. The G and H suffixes add 64 MB DDR2 in the package; H1, H2 and H3 carry 128 or 256 MB DDR3L.
The RK3308 and RK3308B datasheets rate the Cortex-A35 cores at 1.3 GHz; the RK3308B-S datasheet says 1.1 GHz and the -40 C RK3308J and RK3308M say 1.0 GHz. Radxa rates its RK3308B boards at 1.0 GHz, mainline Linux has OPPs to 1008 MHz, and the Rockchip S-version software table stops at 1104 MHz. Sakura Pi documents 1.3 GHz only after raising the CPU supply above its 1.0 V default.
Yes for a headless system: CPU, clocks, eMMC/SD/SDIO, NAND and SPI flash, Ethernet, USB, I2S/TDM, SPDIF and the internal audio codec (since 6.10) are upstream, with six boards in the tree (EVB, ROC-RK3308-CC, ROCK Pi S, ROCK S0, BPI-P2 Pro, Sakura Pi RK3308B). Mainline U-Boot supports the EVB, ROC-RK3308-CC, ROCK Pi S and ROCK S0. Display (VOP), PDM, the VAD and thermal sensing are not in rk3308.dtsi as of Linux 7.3-rc7.
No. The datasheet lists no video decoder, encoder or GPU, and display output is a parallel RGB or MCU panel only. HDMI appears only as ARC audio input on the SPDIF receiver. For video, look at the RK3328, RK3528 or RK3566.
Yes: Radxa rCore-RK3308 (35 x 35 mm stamp footprint, published schematic), Firefly Core-3308BY/JY/MY (136-pin stamp hole, 45 x 40.2 mm, commercial, industrial and automotive grades) and Dusun DSOM-050R (136-pin stamp hole).
Related chips and reading
- RK3328Routers, TV boxes, Klipper hosts
- RK3326 / PX30Handhelds, HMI panels, smart audio, kiosks
- RV1106 / RV1103Small AI cameras, tiny Linux nodes, IP KVMs
- RK3528TV boxes, media players, small routers
- RK3566HMI, e-ink readers, handhelds, CM4-class SoMs, small routers
We'll design your RK3308 board.
Tell us the interfaces, power budget and volume. An engineer replies with questions or a proposal.
Links and facts on this page checked 2026-10-13. Spotted something out of date? Tell us through the contact form.
Compiled from publicly available sources: datasheets, technical reference manuals, vendor product pages, schematics and source code published by their owners and third parties. We link to documents where others host them and do not host, endorse or vouch for them. Everything on these pages, including our own specs, summaries, block diagrams, comparisons, calculators and design notes, is for reference only and may contain errors or be out of date. It is provided as is, and Groundplane is not responsible for errors in it, for third-party documents, or for any design, board or decision based on it. Always check the manufacturer's current datasheet, reference manual and design guidance before you design a board. Rockchip, Allwinner, Raspberry Pi and other product names are trademarks of their owners; we are not affiliated with any of them. See our disclosure.