STMicroelectronics STM32F05 series Reference Manual page 437

RM0091
Example of how to use the DMA burst feature
In this example the timer DMA burst feature is used to update the contents of the CCRx
registers (x = 2, 3, 4) with the DMA transferring half words into the CCRx registers.
This is done in the following steps:
1. Configure the corresponding DMA channel as follows:
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2. Configure the DCR register by configuring the DBA and DBL bit fields as follows:
DBL = 3 transfers, DBA = 0xE.
3. Enable the TIMx update DMA request (set the UDE bit in the DIER register).
4. Enable TIMx
5. Enable the DMA channel
Note: This example is for the case where every CCRx register to be updated once. If every CCRx
register is to be updated twice for example, the number of data to transfer should be 6. Let
us take the example of a buffer in the RAM containing data1, data2, data3, data4, data5 and
data6. The data is transferred to the CCRx registers as follows: on the first update DMA
request, data1 is transferred to CCR2, data2 is transferred to CCR3, data3 is transferred to
CCR4 and on the second update DMA request, data4 is transferred to CCR2, data5 is
transferred to CCR3 and data6 is transferred to CCR4.
DMA channel peripheral address is the DMAR register address
DMA channel memory address is the address of the buffer in the RAM containing
the data to be transferred by DMA into CCRx registers.
Number of data to transfer = 3 (See note below).
Circular mode disabled.
Doc ID 018940 Rev 1
General-purpose timers (TIM15/16/17)
437/742