HD404459 Datasheet, PDF (67/122 Pages) Renesas Technology Corp – 4-bit HMCS400-series microcomputers

HD404459 Series
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 48 Timer Write Register B Upper Digit (TWBU)
• Timer read register B (TRBL: $00A, TRBU: $00B): Read-only register consisting of a lower digit
(TRBL) and an upper digit (TRBU) that holds the count of the timer B upper digit.
The upper digit (TRBU) must be read first, which will result in the count of the timer B upper digit to
be obtained and the count of the timer B lower digit to be latched to the lower digit (TRBL). Then by
reading TRBL, the count of timer B can be obtained when TRBU is read.
Timer read register B (lower digit) (TRBL: $00A)
Bit
Initial value
Read/Write
Bit name
3
2
1
0
Undefined Undefined Undefined Undefined
R
R
R
R
TRBL3 TRBL2 TRBL1 TRBL0
Figure 49 Timer Read Register B Lower Digit (TRBL)
Timer read register B (upper digit) (TRBU: $00B)
Bit
Initial value
Read/Write
Bit name
3
2
1
0
Undefined Undefined Undefined Undefined
R
R
R
R
TRBU3 TRBU2 TRBU1 TRBU0
Figure 50 Timer Read Register B Upper Digit (TRBU)
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