HD404449 Datasheet, PDF (63/123 Pages) Hitachi Semiconductor – HD404449 SERIES

Timer mode register B2 (TMB2: $013)
Bit
Initial value
Read/Write
Bit name
3
2
1
—
—
0
—
—
R/W
Not used Not used TMB21
0
0
R/W
TMB20
HD404449 Series
TMB21 TMB20
0
0
1
1
0
1
R3₀/TOB mode selection
R3₀
R3₀ port
TOB Toggle output
TOB 0 output
TOB 1 output
Figure 45 Timer Mode Register B2 (TMB2)
• Timer write register B (TWBL: $00A, TWBU: $00B): Write-only register consisting of the lower digit
(TWBL) and the upper digit (TWBU) as shown in figures 46 and 47. The lower digit is reset to $0 by
MCU reset, but the upper digit value is invalid.
Timer B is initialized by writing to timer write register B (TWBL: $00A, TWBU: $00B). In this case,
the lower digit (TWBL) must be written to first, but writing only to the lower digit does not change the
timer B value. Timer B is initialized to the value in timer write register B at the same time the upper
digit (TWBU) is written to. When timer write register B is written to again and if the lower digit value
needs no change, writing only to the upper digit initializes timer B.
Timer write register B (lower digit) (TWBL: $00A)
Bit
Initial value
Read/Write
Bit name
3
0
W
TWBL3
2
0
W
TWBL2
1
0
W
TWBL1
0
0
W
TWBL0
Figure 46 Timer Write Register B Lower Digit (TWBL)
Timer write register B (upper digit) (TWBU: $00B)
Bit
Initial value
Read/Write
Bit name
3
2
1
0
Undefined Undefined Undefined Undefined
W
W
W
W
TWBU3 TWBU2 TWBU1 TWBU0
Figure 47 Timer Write Register B Upper Digit (TWBU)
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