Register Descriptions - Renesas Hitachi H8S/2194 Series Hardware Manual

28.3.4

Register Descriptions

(1) Reference Period Mode Register (RFM)
Bit : 7
RCS
Initial value :
0
R/W : W
RFM is an 8-bit write-only register which determines the operational state of the reference signal
generators. If a read is attempted, an undetermined value is read out.
It is initialized to H'00 by a reset, stand-by or module stop.
RFM is accessible by byte access only. If accessed by a word, its operation is not assured.
Bit 7: Clock Source Selection Bit (RCS)
Selects the clock source supplied to the counter. (φs = fosc/2)
Bit 7
RCS Description
φs/2
0
φs/4
1
Bit 6: Mode Selection Bit (VNA)
Selects whether the transition to free-run operation when the REF30 signals are being generated
in sync with the VD signals in REC mode is controlled automatically by the V noise detection
signal, which has been detected by the sync signal detection circuit, or is controlled manually by
software.
Bit 6
VNA Description
0 Manual mode
1 Auto mode
6 5
VNA CVS REX
0 0
W W
4 3 2
CRD OD/EV
0 0 0
W W W
Rev. 2.0, 11/00, page 629 of 1037
1 0
VST VEG
0 0
W W
(Initial value)
(Initial value)