MC68HC705T16 MOTOROLA [Motorola, Inc], MC68HC705T16 Datasheet - Page 43

• Manufacturer Part Number: MC68HC705T16
• Description: High-density complementary metal oxide semiconductor (HCMOS) microcontroller unit
• Manufacturer: MOTOROLA [Motorola, Inc]

5.1
The timer consists of a 16-bit free-running counter driven by a fixed divide-by-four prescaler. This
timer can be used for many purposes, including input waveform measurements while
simultaneously generating an output waveform. Pulse widths can vary from several microseconds
to many seconds. Figure 5-1 shows a block diagram for the Programmable Timer.
Because the timer has a 16-bit architecture, the I/O registers for the input capture and output
compare functions are pairs of 8-bit registers (high byte and low byte). Generally, assessing the
low byte of a specific timer function allows full control of that function. However, an access of the
high byte inhibits that specific timer function until the low byte is also accessed.
Note:
Twelve 8-bit registers are associated with the programmable timer.
A description of each register is provided in the following paragraphs.
MC68HC05T16
– Timer Control Register (TCR)
– Timer Status Register (TSR)
– Input Capture Register
– Output Compare 0 Register
– Output Compare 1 Register
– Counter Register
– Alternate Counter Register
The I bit in the condition code register should be set while manipulating both the high
and low byte register of a specific timer function to ensure that an interrupt does not
occur.
PROGRAMMABLE TIMER
TIMERS
TIMERS
$10
$11
High byte - $12, Low byte - $13
High byte - $14, Low byte - $15
High byte - $16, Low byte - $17
High byte - $18, Low byte - $19
High byte - $1A, Low byte - $1B
5
MOTOROLA
TPG
5-1
5