Data Transfer from Internal Memory to DAC

Data stored in the internal Program Flash Memory (PFM) can be seamlessly transferred to DAC using DMA. The DMA setup configurations are listed in Table 3-5.

Table 1. DMA Setup Configuration (DMA6)
DMA6 Setup
SSA Source Address Beginning of space allocated for audio storage
SSZ Source Size 256 (1 page data from PFM)
SMR Source Memory Region PFM
SMODE Source Address Mode SPTR is incremented
DSA Destination Address &DAC1DATL
DSZ Destination Size 1
DMODE Destination Address Mode DPTR remains unchanged
SIRQEN Start Trigger Enable Yes
SIRQ Start Trigger TMR0 (sampling timer)
SSTP Source Counter Reload Stop Yes - SIRQEN is cleared when source counter reloads
DSTP Destination Counter Reload Stop No - SIRQEN not cleared
AIRQEN Abort Trigger Enable No (stops when DCNT reloads)
AIRQ Abort Trigger N/A
How It Works:
  1. 1.Enable SIRQEN to kick off DMA at the next timer overflow. This allows the DMA data transfer rate to match the sampling timer rate.
  2. 2.The DMA stops when an entire page of audio data has been read.
  3. 3.To read the next PFM page, SSA can be updated with the new address.
  4. 4.Repeat to read as many pages of stored audio data.
Parent topic: Data Transfer Operations