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kafka_dae_control: periods: attempt to prevent invalid configurations #103
Description
In COMPUTER control mode:
- If I try to set
PERIODS:SPto larger thanNUMPERIODS:MAX, I should get an error. - If I'm in period
Nand I try to changeNUMPERIODS:MAXto less thanN, put back to period 0 (user period 1)? - I probably shouldn't be allowed to set
NUMPERIODS:MAXto zero - If I was previously in period N and this was done by
EXTERNALorLOOKUPcontrol mode, then when I change toCOMPUTERcontrol mode this should be verified againstNUMPERIODS:MAXand set back to something valid ifNis larger thanNUMPERIODS:MAX. - As per discussion below,
NOT_USEDis not a real control mode (it was meant to say that this bit-pattern does not correspond to anything in the hardware). Remove references toNOT_USEDin our code.
Activity
FreddieAkeroyd commentedon Jul 30, 2026
Is periodmode of "not used" a hardware option? I was wondering how it differed from computer control with maxperiods of 1
rerpha commentedon Jul 30, 2026
Probably a question for @DaveTempleman
DaveTempleman commentedon Jul 31, 2026
Are you are referring to this "bit5..4 = Period mode 00: computer, 01: look up table 10: not used), 11: external"
If so then it should read "not currently implemented" as I haven't worked out how want to do periods with a look up table. The only stumbling block is if I can store the Look Up Table in FPGA memory or if it needs to be in DDR. Think this comes down to how big we think the Look Up Table Would need to be? In the UDP header we have space for 16bits of periods so I assume I will need to make it 16bits deep and wide?
FreddieAkeroyd commentedon Jul 31, 2026
The streaming software looked to list four specific period modes "not used", "computer", "hardware (internal)", "hardware (external)" - do you mean "not used" is not actually a period mode but that the bit pattern10 in the register is not currently used for anything? In the old system there were just three modes: computer/internal/external.
DaveTempleman commentedon Jul 31, 2026
Yes, sorry for the confusion. There are still the same 3 modes but as using 2 bits there is an unused/undefined option.
I copied the numbers from how DAE3 worked if you want to change it to a more logical mapping of
00 - Computer
01 - Hardware internal - look up table
02 - Hardware external
03 - unused/undefined
Previously with DAE3 if bit 14 was set in the period number then it was dwell period. Given it's currently a 16bit number do we want to change it to the MSB (bit15) that is the dwell period flag?