HD404369 Datasheet, PDF (63/117 Pages) Hitachi Semiconductor – 4-bit HMCS400-Series microcomputer

HD404369 Series
• Timer read register B (TRBL: $00A, TRBU: $00B): Read-only register consisting of the lower digit
(TRBL) and the upper digit (TRBU) that holds the count of the timer B upper digit (figures 44 and 45).
The upper digit (TRBU) must be read first. At this time, the count of the timer B upper digit is obtained,
and the count of the timer B lower digit is latched to the lower digit (TRBL). After this, by reading
TRBL, the count of timer B when TRBU is read can be obtained.
When the input capture timer operation is selected and if the count of timer B is read after a trigger is
input, either the lower or upper digit can be read first.
• Port mode register B (PMRB: $024): Write-only register that selects D₂/EVNB pin function as shown in
figure 46. 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 41 Timer Mode Register B2 (TMB2)
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 42 Timer Write Register B Lower Digit (TWBL)
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