As @carlosspr says. For stall detection to work, the feed rate in your G1 S1 commands must be at least (60 * m915-h-value / full-steps-per-mm) . If your printer has 80 steps/mm @ x16 microstepping, that's 5 full steps/mm. You are using H200 in M915, so the minimum G1 S1 feed rate would be (200 * 60)/5 = 2400.