mc9s12xd256 Freescale Semiconductor, Inc, mc9s12xd256 Datasheet - Page 335

• Manufacturer Part Number: mc9s12xd256
• Description: Hcs12x Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Read: Anytime
Write: Anytime
All bits reset to zero.
The two 8-bit pulse accumulators PAC3 and PAC2 are cascaded to form the PACA 16-bit pulse
accumulator. When PACA in enabled (PAEN = 1 in PACTL), the PACN3 and PACN2 registers contents
are respectively the high and low byte of the PACA.
When PACN3 overflows from 0x00FF to 0x0000, the interrupt flag PAOVF in PAFLG is set.
Full count register access will take place in one clock cycle.
7.3.2.18
Read: Anytime
Write: Anytime
All bits reset to zero.
The two 8-bit pulse accumulators PAC1 and PAC0 are cascaded to form the PACB 16-bit pulse
accumulator. When PACB in enabled, (PBEN = 1 in PBCTL) the PACN1 and PACN0 registers contents
are respectively the high and low byte of the PACB.
Freescale Semiconductor
Reset
Reset
Reset
W
W
W
R
R
R
PACNT7(15) PACNT6(14) PACNT5(13) PACNT4(12) PACNT3(11) PACNT2(10)
PACNT7
PACNT7
Pulse Accumulators Count Registers (PACN1 and PACN0)
0
0
0
7
7
7
A separate read/write for high byte and low byte will give a different result
than accessing them as a word.
When clocking pulse and write to the registers occurs simultaneously, write
takes priority and the register is not incremented.
PACNT6
PACNT6
Figure 7-38. Pulse Accumulators Count Register 2 (PACN2)
Figure 7-39. Pulse Accumulators Count Register 1 (PACN1)
Figure 7-40. Pulse Accumulators Count Register 0 (PACN0)
0
0
0
6
6
6
PACNT5
PACNT5
MC9S12XDP512 Data Sheet, Rev. 2.17
0
0
0
5
5
5
PACNT4
PACNT4
NOTE
0
0
0
4
4
4
PACNT3
PACNT3
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
0
0
0
3
3
3
PACNT2
PACNT2
0
0
0
2
2
2
PACNT1(9)
PACNT1
PACNT1
0
0
0
1
1
1
PACNT0(8)
PACNT0
PACNT0
0
0
0
0
0
0
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