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Original question:

DLPLCR6500EVM: programming guide typo

DLPLCR6500EVM: programming guide incomplete description of USB 1A31 command

Derek Decker
Intellectual 300 points

Part Number: DLPLCR6500EVM

In an attempt to programmatically control the 6500 in Picture On-The-Fly mode, I'm having to deep dive into what every bit means and does. The programmers guide (dlpu018d) usually explains what every bit is for. However, Table 2-121 suggests the first eleven bits determine the number of LUT entries. Eleven bits give up to 2048 entries but the description suggests only 513 are possible (0-512). It is not clear what would happen if a number larger than 512 were entered. Would they simply be ignored?

  • 0
    Intellectual 300 points
    Furthermore, MBOX_DATA (USB 1A34) says the eleven bits for image pattern index has a valid range of 0-255. This suggests 1A31 (above) is not compatible with 1A34. Please confirm.
  • 0 in reply to Derek Decker
    Intellectual 300 points
    Furthermore, Initialize Pattern BMP Load (USB=1A2A aka PATMEM_LOAD_INIT_MASTER) refers to LUT command image index. However, this command (1A2A) only allows 18 (0-17) images. Thus, does this command limit the two commands above from 512 to 18 (1A34) and 256 to 18 (1A34)?
  • 0
    TI__Guru 54430 points
    Derek,

    Question 1 - Values larger than 511 in command 0x1A31 will likely cause a sequence execution error. This would need to be tested.

    Question 2 - This is a little more difficult to explain clearly. The pattern index is an index to the pattern in the entire sequence. However, for loading patterns into the firmware, they must be loaded in complete 24 bit frames. Therefore if you have 36 1-bit images they will be loaded into two image patterns that contains them. The first 24 will be in "image pattern index" 0, and the remaining 12 into "image pattern index" 1. to refer to pattern 26 you would have "image pattern index" 1 at bit position 1 - that is what the last two entries of table 2-123 represent. Therefore if the number of patterns is limited to 512 (even 1-bit patterns), the "image pattern index" can at most be 21 images. For programming it was easier to chose an 8 bit integer value in the algorithm, even though 11 positions were allotted.

    Question 3 - Pre-stored pattern mode "image pattern index" is limited by the size of the flash memory to 18 positions. It operates similarly to pattern on-the-fly mode (which can hold more than 18 by directly loading them into DDR memory).

    Fizix