I just picked up a Sonnet Crescendo G3 300/1M on eBay because it was cheap enough and seemed like it would be fun to play with. This is the "big" card that Sonnet also used for G4 upgrades, vs. the smaller design that appears to have been for G3s only.
I noticed that the G4 version has two GAL22V10Ds, at U20 and U21. These are missing on the G3 version. Does anyone have any idea what these GALs were for, or am I going to have to figure it out?
I know that the later 745x-based upgrades had a full-on FPGA onboard, but these G4 upgrades only used 7400/7410 chips, which are pin-compatible with a 750, so it's not obvious to me what Sonnet would've needed the GALs for. Looks like a delay line was also added at DL1.
G4 with GALs:
G3 without GALs:
I noticed that the G4 version has two GAL22V10Ds, at U20 and U21. These are missing on the G3 version. Does anyone have any idea what these GALs were for, or am I going to have to figure it out?
I know that the later 745x-based upgrades had a full-on FPGA onboard, but these G4 upgrades only used 7400/7410 chips, which are pin-compatible with a 750, so it's not obvious to me what Sonnet would've needed the GALs for. Looks like a delay line was also added at DL1.G4 with GALs:
G3 without GALs:
