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22.2.2 Write handshaking data transfer Handshaking allows data transfers between two asynchronous devices. Write handshaking operates with ‘data ready’ and ‘data taken’ signals. The 6522 provides the ‘data ready’ (CA2 or CB2) signal and accepts the ‘data taken’ (CA1 or CB1) signal from the peripheral device. This ‘data taken’ signal sets the interrupt flag and clears the ‘data ready’ output. See the timing diagram figure 22.5. Selection of operating modes for CA1, CA2, CB1 and CB2 is controlled by the Peripheral Control Register, see figure 22.6. 403
