stm32f0xx_hal_spi.c 关于SPI 的速率描述.
本帖最后由 Depth 于 2016-2-22 17:02 编辑[..]
Using the HAL it is not possible to reach all supported SPI frequency with the differents SPI Modes,
the following table resume the max SPI frequency reached with data size 8bits/16bits:
+-----------------------------------------------------------------------------------------+
| | | 2Lines Fullduplex| 2Lines RxOnly| 1Line |
| Process | Tranfert mode|--------------------|--------------------|--------------------|
| | |Master|Slave|Master|Slave|Master|Slave|
|=========================================================================================|
| T | Polling | Fcpu/32| Fcpu/32 | NA | NA | NA | NA |
| X |----------------|----------|---------|----------|---------|----------|---------|
| / | Interrupt| Fcpu/32| Fcpu/32 | NA | NA | NA | NA |
| R |----------------|----------|---------|----------|---------|----------|---------|
| X | DMA | Fcpu/32| Fcpu/16 | NA | NA | NA | NA |
|=========|================|==========|=========|==========|=========|==========|=========|
| | Polling | Fcpu/32| Fcpu/16 |Fcpu/16 | Fcpu/16 |Fcpu/16 | Fcpu/16 |
| |----------------|----------|---------|----------|---------|----------|---------|
| R | Interrupt| Fcpu/16| Fcpu/16 |Fcpu/16 | Fcpu/16 |Fcpu/16 | Fcpu/16 |
| X |----------------|----------|---------|----------|---------|----------|---------|
| | DMA |Fcpu/4|Fcpu/8 |Fcpu/4|Fcpu/4 |Fcpu/8| Fcpu/16 |
|=========|================|==========|=========|==========|=========|==========|=========|
| | Polling | Fcpu/16| Fcpu/16 | NA | NA |Fcpu/16 | Fcpu/16 |
| |----------------|----------|---------|----------|---------|----------|---------|
| T | Interrupt| Fcpu/32| Fcpu/16 | NA | NA |Fcpu/16 | Fcpu/16 |
| X |----------------|----------|---------|----------|---------|----------|---------|
| | DMA |Fcpu/2| Fcpu/16 | NA | NA |Fcpu/8| Fcpu/16 |
+-----------------------------------------------------------------------------------------+为什么速率限制到这么低？
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