Chapter 11 Enhanced Capture Timer (S12MC9S12XDP51216B8CV2)
MC9S12XDP512 Data Sheet, Rev. 2.11
534 Freescale Semiconductor
When clocking pulse and write to the registers occurs simultaneously, write
takes priority and the register is not incremented.
11.3.2.18 Pulse Accumulators Count Registers (PACN1 and PACN0)
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.
When PACN1 overflows from 0x00FF to 0x0000, the interrupt flag PBOVF in PBFLG is set.
Full count register access will take place in one clock cycle.
NOTE
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.
Module Base + 0x0024
76543210
RPACNT7(15) PACNT6(14) PACNT5(13) PACNT4(12) PACNT3(11) PACNT2(10) PACNT1(9) PACNT0(8)
W
Reset 00000000
Figure 11-39. Pulse Accumulators Count Register 1 (PACN1)
Module Base + 0x0025
76543210
RPACNT7 PACNT6 PACNT5 PACNT4 PACNT3 PACNT2 PACNT1 PACNT0
W
Reset 00000000
Figure 11-40. Pulse Accumulators Count Register 0 (PACN0)