Pavel-
Thanks for the response. What you describe above (i.e. bits 25 and 24 mapping to DAE1 and DAE0) is pretty much what we'd figured was the case based on a reading of the code.
In actual practice, though, it seems these bits are inactive...?
With DAC0 CVBS output active, I've tried the following:
root@dm814x:~# devmem2 0x48105F50
/dev/mem opened.
Memory mapped at address 0x40212000.
Value at address 0x48105F50 (0x40212f50): 0xE000000
This is expected, DAC0 is active, CVBS output.
root@dm814x:~# devmem2 0x48105F50 w 0x0F000000
/dev/mem opened.
Memory mapped at address 0x40081000.
Value at address 0x48105F50 (0x40081f50): 0xE000000
Written 0xF000000; readback 0xF000000
Per spec, this should enable all DACs; per code this should disable all DACs. Either way, DAC0 CVBS output is still active.
root@dm814x:~# devmem2 0x48105F50 w 0x00000000
/dev/mem opened.
Memory mapped at address 0x400cb000.
Value at address 0x48105F50 (0x400cbf50): 0xF000000
Written 0x0; readback 0x0
Per spec, this should disable all DACs; per code this should enable all DACs. Either way, DAC0 CVBS output is still active.
root@dm814x:~# devmem2 0x48105E04
/dev/mem opened.
Memory mapped at address 0x40162000.
Value at address 0x48105E04 (0x40162e04): 0x5
Let's try the VIEN bit in SD_VENC_vmod...
root@dm814x:~# devmem2 0x48105E04 w 0x00000004
/dev/mem opened.
Memory mapped at address 0x40253000.
Value at address 0x48105E04 (0x40253e04): 0x5
Written 0x4; readback 0x4
Deasserting VIEN results in loss-of-signal on both DAC0 and DAC1...
root@dm814x:~# devmem2 0x48105E04 w 0x00000005
/dev/mem opened.
Memory mapped at address 0x4024a000.
Value at address 0x48105E04 (0x4024ae04): 0x4
Written 0x5; readback 0x5
...and re-asserting VIEN results in CVBS output resuming on both DAC0 and DAC1...
Is there something that we're missing here? I've reviewed the latest DM814x Silicon Errata documentation as well, and see no mention that these bits are invalid and/or the DACs are hardwired "on". Is there perhaps another way to disable unused DACs (we're interested in this from a radiated EMI perspective).
Thanks!
-Cory