SWRU626 December 2025 CC3501E , CC3551E
The CC35xx uses the fast clock for active MCU functions and peripherals, as well as for WiFi/BLE functions. This clock is generated from an external XTAL running at 52MHz (HFXT).
The clock signals shown in the diagram above are described in the table below.
| Clock Name | Frequency | Destination | Clock Gating (HW/SW) | Power State | |||
|---|---|---|---|---|---|---|---|
| Active | Host Sleep, Wireless Core Active | Host Active, Wireless Core Sleep | Sleep | ||||
| Device Clocks | |||||||
| HFXT_P, HFXT_N | 52MHz | Fast Clock Analog Module | NA | ON | ON | ON | ON/OFF |
| PLL_CLK | 320MHz | PRCM dividers | HW | ON | ON | ON | OFF |
| HOST_CLK | 160MHz | CPUSS: M33, xSPI, OTFDE, µDMA | HW | ON | OFF | ON | OFF |
| SOC_CLK | 80MHz | Internal resources and peripherals MMR | HW | ON | OFF | ON | OFF |
| Peripherals Clock | 80MHz | Host Peripherals Clock | HW | ON | OFF | ON | OFF |
| Core CLK 80 | 80MHz | Wireless Core | HW (at core) | ON | ON | OFF | OFF |
| Core CLK 40 | 40MHz | Wireless Core | HW (at core) | ON | ON | OFF | OFF |
| ADC Conversion CLK | 80MHz/52MHz | ADC | SW | ON/OFF | ON/OFF | OFF | OFF |
| Peripherals Clocks | |||||||
| SWCLK | 20MHz | DEBUGSS | none | NA | NA | NA | NA |
| SPI CLK | 26MHz (peripheral) 40MHz (controller) | SPI (input/output) | none (peripheral) SW (controller) | NA | NA | NA | NA |
| xSPI CLK | 80MHz | xSPI flash/PSRAM (output) | SW | ON/OFF | ON/OFF | OFF | OFF |
| I2C CLK | 100kHz / 400kHz / 1MHz | I2C (input/output) | none | ON/OFF | ON/OFF | OFF | OFF |
| I2S CLK | 11kHz - 96kHz | I2S (output) | SW | ON/OFF | ON/OFF | OFF | OFF |
| PDM BCLK | 6MHz | PDM (output) | SW | ON/OFF | ON/OFF | OFF | OFF |
| SDMMC CLK | 40MHz | SD card (output) | SW | ON/OFF | ON/OFF | OFF | OFF |
| SDIO CLK | 40MHz | SDIO (input) | SW | ON/OFF | ON/OFF | OFF | OFF |