FREDDIE is memory decoder and timer. Replaces several chips from the XL line. It takes the address and clock from the CPU and multiplexes it with the appropriate timings and signals to use DYNAMIC memory. FREDDIE also buffers the system clock crystal and divides it down then feeds that to GTIA.
Has nothing to do with bank-switching. That's what EMMU does.
It is used in all XEs and in late XLs (XLFs).
CO61991-29 - NCR CO61922 - CITEL