MC68HC705C Motorola, MC68HC705C Datasheet - Page 98

• Manufacturer Part Number: MC68HC705C
• Description: HCMOS Microcontroller Unit
• Manufacturer: Motorola

Capture/Compare Timer
8.4.5 Input Capture Registers
Technical Data
98
NOTE:
Register Name and Address: Input Capture Register High — $0014
Register Name and Address: Input Capture Register Low — $0015
When a selected edge occurs on the TCAP pin, the current high and low
bytes of the 16-bit counter are latched into the read-only input capture
registers (ICRH and ICRL) shown in
reading ICRL inhibits further captures until ICRL is read. Reading ICRL
after reading the timer status register clears the input capture flag (ICF).
Writing to the input capture registers has no effect.
To prevent interrupts from occurring between readings of ICRH and
ICRL, set the interrupt mask (I bit) in the condition code register before
reading ICRH and clear the mask after reading ICRL.
Reset:
Reset:
Read:
Write:
Read:
Write:
Figure 8-11. Input Capture Registers (ICRH and ICRL)
Bit 15
Bit 7
Bit 7
Capture/Compare Timer
= Unimplemented
Bit 14
Bit 6
6
Bit 13
Bit 5
5
Unaffected by reset
Unaffected by reset
Bit 12
Bit 4
4
Figure
Bit 11
Bit 3
3
8-11. Reading ICRH before
MC68HC705C8A — Rev. 2.0
Bit 10
Bit 2
2
Bit 9
Bit 1
1
MOTOROLA
Bit 0
Bit 8
Bit 0