36.7.2 Block Size Register

Name: BSR
Offset: 0x04
Reset: 0x0000
Property: -

Bit 15141312111098 
  BOUNDARY[2:0]  BLOCKSIZE[9:8] 
Access ---R/WR/W 
Reset 00000 
Bit 76543210 
 BLOCKSIZE[7:0] 
Access R/WR/WR/WR/WR/WR/WR/WR/W 
Reset 00000000 

Bits 14:12 – BOUNDARY[2:0] SDMA Buffer Boundary

This field specifies the size of the contiguous buffer in the system memory. The SDMA transfer waits at every boundary specified by this field and the peripheral generates the DMA Interrupt to instruct the software to update SSAR. If this field is set to 0 (buffer size = 4 Kbytes), the lowest 12 bits of SSAR.ADDRESS point to data in the contiguous buffer, and the upper 20 bits point to the location of the buffer in the system memory. This function is active when the DMA Enable bit in the Transfer Mode Register (TMR.DMAEN) is '1'.

ValueNameDescription
0 4K

4-Kbyte boundary

1 8K

8-Kbyte boundary

2 16K

16-Kbyte boundary

3 32K

32-Kbyte boundary

4 64K

64-Kbyte boundary

5 128K

128-Kbyte boundary

6 256k

256-Kbyte boundary

7 512K

512-Kbyte boundary

Bits 9:0 – BLOCKSIZE[9:0] Transfer Block Size

This field specifies the block size of data transfers for CMD17, CMD18, CMD24, CMD25 and CMD53. Values ranging from 1 to 512 can be set. It can be accessed only if no transaction is executing (i.e., after a transaction has stopped). Read operations during transfers may return an invalid value, and write operations are ignored.