HD404356 Datasheet, PDF (50/100 Pages) Hitachi Semiconductor – 4-bit HMCS400-Series microcomputer

HD404358 Series
• Timer mode register B2 (TMB2: $026): Three-bit write-only register that selects the detection edge of
signals input to pin EVNB and input capture operation as shown in figure 34. It is reset to $0 by MCU
reset.
Timer mode register B2 (TMB2: $026)
Bit
Initial value
Read/Write
Bit name
3
2
—
0
—
W
Not used TMB22
1
0
W
TMB21
0
0
W
TMB20
TMB21 TMB20
0
0
1
1
0
1
EVNB Edge Detection Selection
No detection
Falling edge detection
Rising edge detection
Rising and falling edge detection
TMB22
0
1
Free-Running/Reload and Input Capture Selection
Free-running/reload
Input capture
Figure 34 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). The lower digit is reset to $0 by MCU reset, but the upper digit
value is invalid (figures 35 and 36).
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 35 Timer Write Register B Lower Digit (TWBL)
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