Tim1&Tim8 Dma Address For Full Transfer (Timx_Dmar) - ST STM32F101 series Reference Manual

Advanced-control timers (TIM1&TIM8)
14.4.20 TIM1&TIM8 DMA address for full transfer (TIMx_DMAR)
Address offset: 0x4C
Reset value: 0x0000
15 14 13
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Bits 15:0 DMAB[15:0]: DMA register for burst accesses
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:
–
–
–
–
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's
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.
357/1128
12 11 10 9
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A read or write operation to the DMAR register accesses the register located at the address
(TIMx_CR1 address) + (DBA + DMA index) x 4
where TIMx_CR1 address is the address of the control register 1, DBA is the DMA base
address configured in TIMx_DCR register, DMA index is automatically controlled by the
DMA transfer, and ranges from 0 to DBL (DBL configured in TIMx_DCR).
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.
8 7 6
DMAB[15:0]
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DocID13902 Rev 15
5 4 3 2
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RM0008
1 0
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