SERIES-PARALLEL/PARALLEL-SERIES DEVICE FOR VARIABLE BIT LENGTH CONFIGURATION

A serdes device includes circuitry for loading or reading bit configurations into or out of strings of latches of variable length nk+r, where n is the number of bits in a byte, k is the number of whole bytes and r is the number of residual bits, with r being smaller than n. Under the control of a service processor (8), there is formed a ring comprised of the latches of the serializer/deserializer register (14), the latches of the string considered (3 or 4) and a selected number (n-r) of latches of an extension register (16). The bytes to be loaded are sequentially sent to register (14), starting with the byte that contains the residual bits, and n bits are shifted out after loading each successive byte, so that after k+1 shifts the desired configuration will be contained in the string. For reading the contents of a string (for example, string 3), n bits are shifted, register (14) is read out, then k shifts of n bits each are performed, with register (14) being read out after each shift.