ChibiOS Free Embedded RTOS

HI all,

I am trying to use chibios with the STM32 96Boards Sensor board in standalone mode ( not currently supported )
The board runs an stm32f446, and has arduino pin header.

and the first project is a pwm driver for ws2812 driver from joewa's ws2812 github repository.
I am using a config derived from a nucleo f446, but with a 16mhz external oscillator.
PWM output is to the arduino connector D13, which maps to gpio E2,

My pal line mappings are incomplete, but I have remove the nucleo specific entries.
updateing the board.chcfg


in the code I have
palSetPadMode(PORT_WS2812, PIN_WS2812, PAL_MODE_ALTERNATE(WS2812_AF));


If I set HSI and HSE BYPass to true it hangs on

while ((RCC->CR & RCC_CR_HSERDY) == 0)
; /* Waits until HSE is stable.


If HSI and HSE BYPass set to false it runs( as i think it should be), DMA triggers callbacks, and thread run as expected.



Is my approach and setup correct with the following driver setup


#define PORT_WS2812 GPIOE
#define PIN_WS2812 2 // arduino connector pin D13
#define WS2812_TIM_N 4 // timer, 1-11
#define WS2812_TIM_CH 3 // timer channel, 0-3
#define WS2812_DMA_STREAM STM32_DMA_STREAM_ID(1, 6) // DMA stream for TIM4_UP
#define WS2812_DMA_CHANNEL 2



and mcuconf.h


#define STM32_HSI_ENABLED TRUE
#define STM32_LSI_ENABLED TRUE
#define STM32_HSE_ENABLED TRUE
#define STM32_LSE_ENABLED TRUE
#define STM32_CLOCK48_REQUIRED TRUE
#define STM32_SW STM32_SW_PLL
#define STM32_PLLSRC STM32_PLLSRC_HSE
#define STM32_PLLM_VALUE 16
#define STM32_PLLN_VALUE 336
#define STM32_PLLP_VALUE 2
#define STM32_PLLQ_VALUE 2
#define STM32_PLLI2SN_VALUE 192
#define STM32_PLLI2SM_VALUE 16
#define STM32_PLLI2SR_VALUE 2
#define STM32_PLLI2SP_VALUE 2
#define STM32_PLLI2SQ_VALUE 12
#define STM32_HPRE STM32_HPRE_DIV1
#define STM32_PPRE1 STM32_PPRE1_DIV4
#define STM32_PPRE2 STM32_PPRE2_DIV2




#define WS2812_AF 2 // af2 for pwm on timer 4 as per manual




Many thanks for any input/direction.


Oli

Hi,

Not sure, exactly what is your question?

The general approach looks right.

Giovanni

Many thanks for looking.

Is it correct to set HSE BYPASS and HSI BYPASS to false then ( for external crystal)?

Oli

It needs to be TRUE for external oscillators or external clock sources, FALSE for regular crystals. See the RCC section in the STM32 RM.

Giovanni

Thought so, so I guess the key issue is that HSE is never stable and hangs in hal_lld.c.

((RCC->CR & RCC_CR_HSERDY) == 0)

Any clues what might cause this?

Oli

Sorry. My bad. Get it now,

Thanks for your help.

My fault about STM32_HSE_BYPASS, it should be defined/undefined rather than TRUE/FALSE.

Giovanni