2 stop phase, Figure 75. stop (p) signaling, 3 ack/nack – Intel CONTROLLERS 413808 User Manual
Page 646: Figure 76. ack (a) signaling, Figure 77. nack (n) signaling, 4 wait states, 75 stop (p) signaling, 76 ack (a) signaling, 77 nack (n) signaling, Smbdat