Hitachi AP1 Data Book page 244

HMCS404C----------------------------------------------------------------
Table 12. Timer Mode Register B
TMB
Bit 3
Auto·reload Function
o
No
Yes
TMB
Prescaler Divide Ratio,
Bit 2 Bit 1
Bit 0
Clock Input Source
0 0
0
+2048
0 0
1 512
0
1 0
128
0
1 1
32
1 0
0 8
1
0 1
4
1
1 0
2
1 1
1 INTI (External Event Input)
• TIMER-B (TCBL: $OOA, TCBU: $OOB)
TLRL: $OOA, TLRU: $OOB
TIMER·B consists of an 8-bit write-only Timer Load Regis-
ter, and an 8-bit read-only Timer/Event Counter. Each of them
has a low-order digit (TCBL: $OOA, TLRL: $OOA) and a high-
order digit (TCBU: $OOB, TLRU: $OOB).
The Timer/Event Counter can be initialized by writing data
into the Timer Load Register. In this case, write the low-order
digit first, and then the high-order digit. The Timer/Event
Counter is initialized at the time when the high-order digit is
written. The Timer Load Register will be initialized to $00 by
the MCV reset.
The counter value of TIMER-B can be obtained by reading
PMR:$ 004
the Timer/Event Counter. In this case, read the high-order digit
first, and then the low-order digit. The count value of low-order
digit is latched at the time when the high·order digit is read.
• TIMER-A Interrupt Request Flag (lFTA: $001,2)
The TIMER-A Interrupt Request Flag is set by the overflow
output of TIMER-A.
• TIMER-A Interrupt Mask (lMTA: $001,3)
TIMER-A Interrupt Mask prevents an interrupt request
generated by TlMER-A Interrupt Request Flag.
Table 13. TIMER·A Interrupt Request Flag
TIMER·A Interrupt
Request Flag
o
Interrupt Request
No
Yes
Table 14. TlMER·A Interrupt Mask
TIMER·A Interrupt
Mask
o
Interrupt Request
Enable
Disable (Mask)
• TIMER-B Interrupt Request Flag (lFTB: $002, 0)
The TIMER-B Interrupt Request Flag is set by the overflow
output of TIMER-B.
• TIMER-B Interrupt Mask (lMTB: $002, 1)
TIMER-B Interrupt Mask prevents an interrupt request
generated by TIMER-B Interrupt Request Flag.
SMR:$ 005
Transfer clock selection
R.o/SCK pin mode selection
' - - - - - - R. a ISO pin mode selection
L -_ _ _ _ _ _ _
R.I/SI pin mode selection
L -_ _ _ _ _ _ _ _ _
R3a/ iNT o pin mode selection
L -_ _ _ _ _ _ _ _ _ _ _ _
Ru/lNTI pin mode selection
TMA:$008
TMB:$009
I><ITMA21TMA ,I™AOI
. ' l'
L
TIMER·B input clock selection
r
l
Auto-reload function selection
~
TIMER·A input clock selection
Fig. 14 Mode Register Configuration and Function
242