DMA Data Transfer Length Examples

Versal ACAP Technical Reference Manual (AM011)

Document ID
AM011
Release Date
2022-04-26
Revision
1.4 English

The length of a data transfer is defined by one or more command words. Each command word includes a byte count. There are two ways to define the byte count. The method is defined by [EXPONENT]:

  • 0: Byte count is in [imm_data]. Range is 0 to 128 (80h) bytes.
  • 1: Exponent byte count = 2^[imm_data]. Range is 2, 4, 8, 16, and to megabytes.

Programming Examples

There are four data transfer length examples. Set [data_transfer] = 1.

Table 1. QSPI Data Transfer Length Examples
Byte Count [imm_data] [exponent]
64 Byte Transfer
  40h 0
128 Byte Transfer
  80h 0
1000 Byte Transfer - Option 1
  09h 1
  08h 1
  E8h 0
1000 Byte Transfer - Option 2
  08h 1
  08h 1
  08h 1
  E8h 0
1 GB Transfer
  1Eh 1