MITSUBISHI MICROCOMPUTERS
M37754M8C-XXXGP, M37754M8C-XXXHP
M37754S4CGP, M37754S4CHP
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
As shown in Figure 19, the timer Bi count start bit is at the same ad-
dress as the timer Ai count start bit. The count is decremented, an
TIMER B
Figure 35 shows a block diagram of timer B.
interrupt occurs, and the interrupt request bit in the timer Bi interrupt
control register is set when the contents becomes 000016. At the
same time, the contents of the reload register is stored in the counter
and count is continued.
Timer B has three modes: timer mode, event counter mode, and
pulse period measurement/pulse width measurement mode. The
mode is selected with bits 0 and 1 of the timer Bi mode register (i=0
to 2). Each of these modes is described below.
(1) Timer mode [00]
Figure 36 shows the bit configuration of the timer Bi mode register
during timer mode. Bits 0 and 1 of the timer Bi mode register must
always be “0” in timer mode.
Timer Bi does not have a pulse output function or a gate function like
timer A.
When data is written to timer Bi halted, it is written to the reload reg-
ister and the counter. When data is written to timer Bi which is busy,
the data is written to the reload register, but not to the counter. The
new data is reloaded from the reload register to the counter at the
next reload time and counting continues.
Bits 6 and 7 are used to select the clock source. The counting of the
selected clock starts when the count start bit is “1” and stops when
“0”.
The contents of the counter can be read at any time.
Data bus (odd)
Data bus (even)
(Lower 8 bits)
(Higher 8 bits)
Clock source selection
• Timer
Pf2
• Pulse period measurement/Pulse
width measurement
Reload register (16)
Pf16
Pf64
Pf512
Addresses
Counter (16)
Timer B0 5116 5016
Timer B1 5316 5216
Timer B2 5516 5416
Polarity selection
and edge pulse
generator
Event counter
TBiIN
(i = 0 – 2)
Count start bit
(4016)
Counter reset
circuit
Note: Perform write and read to/from timer Bi register in the condition of 16-bit data length : data length flag (m) =“0”.
Fig. 35 Timer B block diagram
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RENESAS [ RENESAS TECHNOLOGY CORP ]
