network. This feature is useful because it minimizes the need for human intervention. When a value placed in the Tentative ID Register matches the Node ID of another node on the network, the TENTID bit is set, telling the software that this NODE ID already exists on the network. The software should periodically place values in the Tentative ID Register and monitor the New Next ID bit to maintain an updated network map.
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OSCILLATOR
The COM20020 contains circuitry which, in conjunction with an external parallel resonant crystal or TTL clock, forms an oscillator.
If an external crystal is used, two capacitors are needed (one from each leg of the crystal to ground). No external resistor is required, since the COM20020 contains an internal resistor. The crystal must have an accuracy of 0.020% or better.
The XTAL2 side of the crystal may be loaded with a single
The user may attach an external TTL clock, rather than a crystal, to the XTAL1 signal. In this case, a 390Ω
