Renesas Hitachi H8S/2191, Hardware Manual, Page: 653 / 1065

Rev. 2.0, 11/00, page 626 of 1037
28.3 Reference Signal Generators
28.3.1 Overview
The reference signal generators consist of REF30 signal generator and CREF signal generator,
and they create the reference signals (REF30 and CREF signals) used in phase comparison, etc.
The REF30 signal is used to control the phase of the drum and capstan. The CREF signal is
used if the reference signal to control the phase of the capstan cannot be shared with the REF30
signal in REC mode. Each signal generator consists of a 16-bit counter which has the servo
clock
φ
s/2 (or
φ
s/4) as its clock source, a reference period register and a comparator.
The value set in the reference period register should be 1/2 of the desired reference signal
period.
28.3.2 Block Diagram
Figure 28.6 shows the block diagram of the REF30 signal generator. Figure 28.7 shows that of
the CREF signal generator.